Growing Cannabis From Seed Indoors

Learn how to grow weed indoors with this step-by-step guide that'll teach you exactly how to turn a seed into a smokable dried flower. Free eBook included. Growing marijuana starting from seeds can be a daunting task. Luckily we've put together the ultimate guide for growing weed from seeds! Growing cannabis indoors. Don’t worry if you have never grown cannabis indoors before, it’s not complicated and most people can master the basic skills.

How to Grow Weed Indoors for Beginners [Follow-Along Guide]

I’m here to tell you that growing weed indoors step-by-step is easy. Just follow along.

Because it’s the first choice of thousands of beginner growers, I’ve decided to put together the most comprehensive soil weed growing guide on the internet.

In this guide, we will go through the whole growing process, from choosing the seeds and soil to harvesting and curing the buds. Hopefully, by the end of this guide your cannabis growing knowledge will grow as much as your plant.

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Preparation stage

The first week (or week 0 as I like to call it) is when you prepare your grow.

It doesn’t necessarily have to be a whole week, however it can often be longer.

You might think:

“So, it’s not a week at all?”

And you’d be right.

You won’t be doing any growing this week as you can’t grow plants without the seeds first.

Week 0 is focused around finding the best soil, seeds, lights and setting up your growing tent.

Even if you are growing hydroponic marijuana you have to do the prep stage, which might be even longer for hydroponic setups.


For this indoor soil growing guide we will use one of the most popular strains ever: White Widow.

But, we won’t use just any White Widow.

For this occasion we will use the autoflowering version of this plant.

Well, for a few simple reasons:

Autoflowering plants are smaller, but they don’t cut down on the yield, they are easier to grow, and they grow faster than regular plants.

You will want only feminized seeds for this grow as male plants do not grow flowers.

“Your plant is only as good as your soil.”

I find this to be one of the biggest truths of growing cannabis.

Beginner growers often experience problems with their soil, such as malnutrition and over-watering.

Both of these will have a long term effect on your plant if not dealt with in the quickest manner.

This is not to say that cannabis won’t grow in slightly bad conditions, far from that.

It’s called “weed” for a reason. It will grow even in sub-par conditions, however the end result might not be what you hoped for.

So, in order to avoid any confusion, do your best to get the perfect soil, and if you fail, you can still make it up by adding nutrients.

Feel free to buy any of the branded soil mixes, except for those that are labeled “extended release”as they will release nitrogen to your plant roots for up to 6 months, meaning that you will have n0 control over the pH levels of your soil.

The best option out there for first-time growers is “Super Soil”, a special mix of soil that can be found in stores. KindSoil is one of the more popular brands of Super Soil.

With any Super Soil mix you won’t have to add any nutrients, as the mix comes premade, so water will be the only thing you add to it—by watering the plants.

Fun fact:

Did you know that earthworms in soil can increase the yield up to 75%? According to scientists from Netherlands, earthworms might be one of the most important parts of a soil-based grow.

However, this study was done on wheat plants so I wouldn’t suggest you throwing earthworms in the mix if you haven’t had at least a dozen successful grows.

Lighting setup

Lights are super important for growing cannabis and insufficient lighting is one of the biggest reasons why many indoor grows fail.

Lighting depends totally on the size of your grow.

Basically there are 2 most common options for lighting:

  • LEDs
  • CFLs (Compact Fluorescent Lights).

CFLs give off more heat than LEDs and are better suited for growing in small spaces, such as tents.

Their downside is that they tend to spend more energy and you will have to readjust them more often than LEDs.

So, my end recommendation is this: if you have room for LEDs and you are willing to go through the hustle of setting up LEDs, be my guest.

For a small first time grow, I would suggest getting a CFL setup with lights up to 300W.

Keeping CFLs close to the plants will bring in the best yields and ensure the biggest plant growth.

The tent

Growing tents are perfect for those that tend to grow in their garage or colder areas of the house, as the tent holds the warmth within itself, helping plants get bigger as soon as possible.

If you plan on growing marijuana in a closet, or a similar closed space that doesn’t let too much heat out, I would suggest that you approach it with caution.

Either way, the most important thing is to keep the temperature at a constant 25°C (77℉).

In case you do go with a tent, you will have to extract the air from the tent, which is removed using a fan that sucks the air out through tubes.

Most modern tents have a carbon filter which prevents the smell of weed leaving the tent, so keep that in mind when shopping for one.

If you still think you can make do without a tent, then get ready to spend some money on fans and/or ventilation systems.

Most modern air extractor fans include temperature and moisture controllers, which will come very handy when calculating your VPD (we’ll get to that later), so I strongly suggest you get one of those.

Pro tip: if you have cats you are going to want to get a tent. Just trust me on this one. I’m saving you money, effort and a lot of nerves.

Light schedule for growing weed indoors

Light periods for autoflowering plants are really easy to grasp:

All you have to do is keep the light turned on.

Like, all the time.

I am not joking when I say that you should keep the lights on 24/7.

Giving 24 hours of light is crucial when growing autoflowering plants, as it may give them the best chance to grow bigger in the vegetative stage and then eventually flower when their time comes.

Autoflowering plants do not need darkness.

Autoflowering plants are not dependent on changes in the light cycle to commence flowering.

This is why they can be grown using a light cycle of anything from 16 to 24 hours daily.

This is also what makes them perfect for first time growers as light periods are one less thing to worry about.

Germination & seedling stage

Time to put those girls into action!

But first, some more prep.

VPD for weed

Creating the perfect environment for your plants doesn’t necessarily end with buying all the right gear.

You will have to know how to properly set it up, and more importantly, how to make the perfect atmosphere for your plants to grow to their potential.

Dehumidifiers decrease environmental moisture and release heat, which can be helpful in certain cases like very moist and cool areas, such as basements.

If you want know how to grow big buds indoors, you have to understand the importance of VPD.

Whether you are growing weed in a closet or a tent, you will have to control the atmosphere.

Humidity is one of the more important factors to control and this is in part due to the fact that different humidity levels are best for different growing stages.

In general, the air humidity for growing weed indoors is as follows:

One thing which is closely connected to air humidity is VPD.

VPD stands for Vapor Pressure Deficit, and it represents the difference between the pressure of water vapor in 100% saturated air at a certain temperature (leaf’s vapor pressure) and actual vapor pressure in the air surrounding the plant.

Plants with higher VPD values will generally have a higher transpiration rate and increased nutrient movement.

Germinating weed seeds

Learning how to germinate a weed seed is a piece of cake, and also the first step you will take towards your new hobby.

Germinating seeds is a process of forcing them to begin to grow and put out roots.

Seeds can be germinated in many ways and the first time you do it you will get a hang for it because there isn’t really too much science behind it.

How to germinate weed seeds?

There are several ways to do this.

Germinating seeds in soil

Germinating seeds in soil is the easiest way to do it because all you have to do is toss them in your pot, cover with some dirt and douse with water.

You only need the soil to be damp so make sure you do not over water it. You can use clear kitchen plastic to wrap the tops of the pots to maintain humidity. Keep the pots in a warm area.

Germinating seeds in water

Germinating seeds in water requires even less effort than germinating seeds in soil.

You literally just have to throw them in a cup of water for 14-18 hours.

One thing that makes this way better than germinating in soil is that you can see if a seed is bad by checking if it didn’t sink. Those that sink are good.

After the seeds start rooting, move them on a damp paper towel and cover with another damp paper towel.

Place the paper towel covered seeds in a dark area and they will grow roots in a matter of days.

After that, all you have to do is move them into a pot.

Germinating seeds with paper towels

For this method, you take a couple of seeds, put them on a damp paper towel and cover with another one, after which you store them somewhere dark.

After a few days you should see roots embedded in the paper towels.

You can do this with gauze and cotton wool as well.

Seedling stage

Seedling stage begins once you’ve moved your seeds from the paper towel into the pot and you start seeing the first leaves break out from the ground.

Here’s a photo of a plant a few days into its seedling stage:

That is exactly what your plant will look like maybe a week after you’ve moved the seeds into the pots.

You don’t really have to do much during the seedling stage.

You don’t even have to water the plants too much as you’ll want the soil to be a bit dry so that the roots can catch better.

You might be thinking, “This man is crazy!”, and you’d be right.

But, letting your plant root strong is a great idea during the seedling stage, just make sure you don’t over water and suffocate the plant.

Over-watering is one of the biggest mistakes you can make, but we’ll get to that in a bit.

One of the most important things to remember for the seedling stage is that you will want to move your plants in a bigger pot as soon as you see the first few leafs show.

Knowing how and when to transplant your plants is perhaps the best knowledge we can pass onto new growers, as leaving plants in small pots can choke them up, while moving them too early can have terrible effects, especially if you don’t do it right.

Further along the road you will most likely have to re-pot the plants again.

I strongly suggest you move the plants as soon as you see the first leaves appear.

The second re-potting should happen once your plants have rooted in firmly and appear ready to be moved—this means that the plant looks stable enough to be moved.

Whatever you decide to do regarding re-potting, keep one thing in mind: The less root damage the better.

Vegetative stage

Vegetative stage starts when you see that the plant is looking more like a weed plant than just a regular plant, meaning that it has clear weed-like characteristics.

You will start seeing the recognizable fan leaves and many branches stemming from the trunk, alongside that familiar skunky smell.

Vegetative stage starts roughly around the second week for most autoflowering plants, but for others it might start in the third week.

Either way, once your plant starts growing in size by the day you will know that you successfully reached the vegetative stage.

Watering weed plants

Watering weed plants is a tricky business if you’ve never watered plants in your life.

Most growers water their plants from the tap so there aren’t really any reasons why you shouldn’t do the same.

The amount of water you will use for your plants varies depending on the specifics of your grow and the environment in which you hold the plants.

It also depends on the size of the plant, air temperature, soil composition, water quality and the capacity of your air filtration systems.

However, seeing how this is intended for beginner growers we won’t go in depth too much with watering.

Let me just leave it at these 3 things:

  1. Water whenever you feel that the top of the soil is dry
  2. Bigger pots — water less often, smaller pots — water more often
  3. Make sure you have appropriate drainage (to avoid overwatering)

Pro tip: Get yourself a bottle of carbonated water, and sprinkle the weed leaves. Carbonated water has CO2, which your plants crave.

How to clone weed plants

Similarly to re-vegging autoflowering weed strains, cloning them is extremely hard or next to impossible to do.

This is due to the fact that autoflowering strains have grown in the northern areas of the planet in which they had limited time to flower.

Cloning an autoflowering seed will create a plant of the same age as the mother plant.

Clones share the exact same genetics as the mother plant, which includes their age.

So, if this is your first grow, chances are that you won’t even try cloning a plant.

If you’re growing a photosensitive strain, however, cloning should be a piece of cake.

  1. Contrary to popular opinion, don’t cut off the most bottom node. Cut at least the 2nd or 3rd node.
  2. Fill a solo cup with soil and punch a hole on the top of the soil about 10 cm deep.
  3. Shave off a bit of the skin on the bottom of the cutting so it can form roots more easily.
  4. Stick the freshly cut branch in the hole you just punched and water your new plant.

Cloning weed plants is a great way to save money and keep growing the same plant with great genetics over and over again. You can clone one plant as many times as you want, and the clone of that clone.

Hell, cloning works even with cats.

Flowering stage

Once your plants reach a decent height and size it is time to flower.

Since we are growing an autoflowering strain, you won’t have to put any effort into changing the light schedule or anything.

Once your plant feels the time is right, it will start flowering.

How to know if your plant is male or female?

“Feminized cannabis seeds are bred to contain no male chromosomes, thus ensuring that every plant grown from them will flower as a female and be able to produce the crop of resinous buds sought by most growers”.

But, what happens if you buy random seeds which aren’t feminized?

Well, in that case you will simply have to sprout all the seeds, and wait for them to grow up a bit.

There are some general rules that will help you determine the sex of your weed plant:

  1. Male plants mature faster, most of the time about two weeks before females;
  2. Male plants also have “false buds” which are actually pollen sacs;
  3. Male plants have flowers while females still have pistils at this point.

It is important to keep in mind that cannabis plants can also be hermaphrodites, which means that one plant has both male and female traits.

Pro tip: It is very important that you keep male and female plants separate (or toss the male plants away) as there is a chance that male plants might ruin your grow by fertilizing the female plants.

Post-harvest stage

Most autoflowering plants will show best results around the 11th or 12th week, which is usually a great time to harvest.

But, before you cut your flowers and start drying, here are 2 things to know before you throw away the remaining pieces of the plant:

  • Harvested plants can grow again and bring more crops (unless they are autoflowering strains) by re-vegging the plant;
  • You can still clone the plant that you just cut up as long as there are healthy leaves.

Make sure that you don’t rush too much with harvesting, as cannabis needs time to develop higher levels of THC, so harvesting a bit later is a lot better than harvesting too soon.

How to re-veg weed plants

To reveg a weed plant means to send it back to the vegetative phase right after the harvest.

Now, I know I said that we will be using an autoflowering seed for this, and the common knowledge is that autoflowering plants cannot be re-vegged.

However, let us pretend again for a minute that we started with a photosensitive seed, in order to show you how re-vegging works.

You might wonder:

“Why reveg weed when you’ve already harvested the plant?”

There are multiple answers to this question:

  • If you had a great yield and you want to repeat the same results;
  • If you don’t want to spend money on new seeds;
  • If you want the same genetics but different results.

So, in order to re-veg the plants you will first have to harvest it.

  1. Cut off all the bigger branches and just leave the trunk of the plant snapped with a few of the smaller branches remaining
  2. Those smaller branches should have a few flowers on them. From these flowers you will see new leafs appear and grow once the plant starts to re-veg
  3. Put the plant back into the growing room and give it 18 hours of light.

You will see new branches appear from the old flowers and once it hits a decent size, put it back to 12 hours of light and 12 hours of dark so that it may flower.

Most plants that get re-vegged will start growing in a bushy manner rather than straight up as they used to.

This is a slow process so don’t be hasty and take your time taking care of the plant as it is a hard process for the plant as well.

How to dry weed

There are 2 things to keep in mind when drying weed:

  1. The room has to have a certain level of humidity, which is around 50%-60%;
  2. The optimal temperature for your drying room is 21°C (70°F).

For best results, you should dry your buds slowly over the course of 3-7 days.

The drying time depends heavily on the climate in your area. In high-humidity climates the drying process will likely last longer, and vice versa.

Experienced smokers know how a properly dried bud feels in the hand, so if you are not certain don’t be afraid to ask.

Here are a few rules to keep in mind when you’re drying buds:

  1. Keep the area clean and dust-free;
  2. Control humidity and temperature (50%-60% and 70°F or 21°C);
  3. Remove the big leaves and hang the pruned colas and buds upside down on a clothing line or wire;
  4. Keep them properly spaced out, especially in relatively humid drying rooms;
  5. Move the nugs to the curing jars once the twigs start snapping.
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Once you’ve moved your buds to the curing jars, the curing process begins.

If you wanna read in depth about drying weed, click here for our full article on how to dry weed.

How to cure weed

Curing marijuana buds is the last step in producing a smokable flower. After curing, your weed will have a much more impressive smell and taste.

Here are some of those big truths about properly drying and curing marijuana:

  • This process breaks down chlorophyll and improves taste and smoothness of the smoke;
  • It will bring out the specifics of your strain when done right, such as the smell and fine flavors;
  • Less chances of mold appearing on your buds.

Check out the photo below for a comparison of well dried and cured weed and poorly dried and cured weed.

Here’s a 5 step tutorial on how to cure weed:

  1. Trim off the smaller leaves and stems that you find remaining after the drying process;
  2. Place the buds in an airtight mason jar, but make sure you don’t cram them up inside. They need some space to cure properly;
  3. Place the jars in a cool, dark place, and make sure there is no sunlight as it breaks down cannabinoids. Make sure you take off the lids every day for 60 minutes to get the fresh air in;
  4. Control the temperature (around 70° Fahrenheit or 20° Celsius) and humidity in the jars around 60% by using humidity packs;
  5. Cure your buds for at least 4 weeks to get the optimal potency and taste, and if you aren’t in a rush you can cure for 6-8 weeks for high-grade buds.

Many people have used small refrigerators for curing weed, as it is fairly easy to control the environment within with heat and humidity packs.

Curing weed in a fridge might be a great way to start if you’ve never done it before.

It is easy, it is convenient as little to no smell is left behind, and there is no way the light will come in.

Go wild

Now it’s up to you to get started and go wild.

Growing weed can be a great hobby for all those that have enough time and passion for smoking cannabis.

Young adults do it all over the US and Canada, just as much as retired folks because it doesn’t require much to be good at it.

Experience is perhaps the biggest factor in growing weed, so don’t be surprised if your first crop doesn’t yield much or the buds don’t look like the ones you buy in a medical dispensary.

These things depend on just about everything, from the strain you are growing to lamps that you use and how long you dried and cured buds after harvesting them.

If you ever get stuck, or things start going south (leaves going yellow, mites problems, etc.) don’t be afraid to ask for help. There are people out there just waiting to hear your problems and see your plants. Many Facebook groups are named “Growers helping growers” so it might be a great idea to join one, just in case you need advice and assistance over the course of your grow.

Grow Weed Starting From Seed

“Don’t judge each day by the harvest you reap but by the seeds that you plant.”

Growing your own cannabis plant starting from seed is a remarkable journey. Understanding the biology of the plant is one thing, but comprehending how a little miracle bean can turn into a gigantic tree producing flowers that can affect your body and mind is nothing short of an evolutionary miracle. Or rather a co-evolutionary story of plant and human.

Start Growing Weed From Seed

Our favorite thing about growing your own weed starting from a seed , rather than a clone, is that you get to see the full life cycle and enjoy a plant that is unique, just like you. An entirely new genetic makeup will enter the world for the first time, and if you’re lucky, something remarkable might be born.

Raising a cannabis seedling , however, requires some patience, gentle hands, and a smidgen of luck. Thankfully pot seeds are remarkably vigorous because they are what’s called endosperm seeds , which means they have almost pre-formed cotyledon leaves before you even add water. Below is a brief guide on the techniques we have found yield the most success when starting seeds and raising your seedling to a healthy plant ready for transplanting. And, don’t forget, a Pot for Pot’s Complete Grow Kits take the guesswork out so you always wind up with a splendid harvest!

1) Germinating Your Cannabis Seed

To accelerate germination, soak your seed in a small container with lukewarm water and place it in a dark and warm place (like a kitchen cabinet) for 12-24 hours, but no longer. By drenching the seed, it absorbs the water thoroughly, activating the germination process on a physical and chemical level. Doing this helps to loosen the shell as it becomes a little softer making it easier for the embryo to crack it open. When your seed sinks to the bottom, it is ready to be planted, and sometimes the seed will pop out a small taproot. A seed can still be planted though if it does not sink or put out a taproot. When a seed pops a taproot (often called a tail), it becomes more vulnerable and it is better to plant it before this root emerges.

2) Planting Your Weed Seed

We see best results with seedling pellets that are made of a mix of compressed peat moss and coco husk. To expand, soak it in water for 10 to 15 minutes. Using warmer, lukewarm water, instead of cold water, will speed up the time the pellet takes to fully expand. Once your seedling pellet has absorbed enough water and has expanded to its maximum size, gently squeeze to remove excess water. The growing medium should be like a damp sponge that would not leave streaks on the table. Dig a small hole about 1/4 inch deep for your seed. Use a spoon to lift the seed out of its bath. If it has popped out a taproot be careful not to damage it. Gently place the seed into the hole and lightly cover it with dirt from the pellet. Now that you have started the germination process, your seedling will come above ground within two weeks. The older the seed, the longer it takes for it to germinate.

Want an easy-to-use starter kit for Cannabis seedlings? Check out our Seedling Starter Kit, perfect for nurturing your germinated seeds into viable, healthy plants.

3) Weed Seedling Sprouts

Perhaps the most exciting stage, your plant baby will come above ground in 1-2 weeks, with the average popping up in 5 to 7 days after planting. As your seedling comes above the soil, its shell might take a few days to fall off. It’s best to leave it alone, nature has the job covered. If it does not come above ground after about two weeks, the chance of success is dramatically reduced, and it’s best to try again. Even the best seeds have an 85% germination rate. When your seedling comes above ground, it is going to want to see a direct light source.

Save Money – No Tent Needed

Organic Cannabis Soil Recipe

Avoid Common Mistakes

4) Lighting for Your Cannabis Seedling

Marijuana seedlings require a medium amount of light — enough to get energy to grow, but not too much light that to get burned. Leaving your seedling in direct sunlight will cause the leaves to curl, while too little light will cause the seedling to stretch. If growing outside, seedlings want to see a direct light source to stop them stretching. If inside, a sunny windowsill with more than half a day of sunlight works wonders. Otherwise, 24 to 30 inches from a grow light is an excellent supplement. Your seedling should not stretch more than 6 inches at most.

5) Watering Your Cannabis Seedling

For cannabis plants young and old, it’s best to use bottled, distilled, or filtered water as these are without chlorine. If using tap water, let it sit for 48 to 96 hours before watering to dissipate any chlorine. Chlorine can also be eliminated by boiling for 20 minutes. Under normal conditions, after soaking your seedling pellet, it should contain all the moisture your plant needs before it comes above ground. As it grows, it will only need about a shot glass worth of water at most per week to keep the medium damp. Seedlings don’t drink a lot of water, which makes sense given their size. Your plant will do better in a growing medium which is damp but not soaking wet. Overwatering is just as deadly as drying out!

Damping off happens when the seedling is in too moist of an environment. The young plant’s immune system is not strong enough to ward off a fungus that results in the plant rotting from the bottom of the stem. When this happens, the plant will bend over and die if not treated. To help fight the infection, lightly spray a 0.5% solution of hydrogen peroxide around the affected area. However, the best option is to avoid this by not exposing your seedling to too much moisture.

6) First Cannabis Seedling Leaves & Hardening Off

The first set of leaves to come above ground are called the cotyledons . These little leaves are packed with energy and will grow to about 1/4 in in size before eventually falling off. Your second leaves to emerge will be single blades and will be serrated, looking like regular pot leaves.

They will become several inches in length. During their growth your first actual set of leaves will appear. These are typically three blades. Around this time is when your plant is “hardening off”. You will notice that the stem will start to develop a thicker skin and harden off. As the leaves of the plant get bigger, they can gradually handle more sunlight, so move it into more direct light– the more light the better!

7) Transplanting Cannabis Seedlings

About 10 days after germination, when the baby cannabis plant has hardened off, roots will start emerging from the bottom of your seedling pellet and the plant is ready to be transplanted into a bigger pot. Be very careful not to damage the roots during this stage. Any stress will slow its growth.

Dig a small hole in your bigger pot for the seedling, sprinkle some rooting booster in the bottom of the hole then carefully plant the whole seedling pellet holding your weed baby.

Now bury so the base of its stalk is level with the topsoil. Give it a watering to set the roots in the ground, then hold off watering until you pick up the pot and it feels light in weight.

Are you ready to transplant your seedlings? Shop our best selection of cannabis starter growing kits from small to large pots.

8. Separating the Girls from the Boys

At about 4-6 weeks into your plant’s growth , you’ll be able to determine the sex of the plant. You’ll want to separate and dispose of any male plants. This is an important step for growing marijuana because the female plants are more potent and valuable. You also don’t want male plants to compromise the growth of your female plants.

Why Do You Only Want Female Weed Plants?

Only female marijuana plants produce THC buds that are high in potency. You want to make sure your Cannabis plants are all female. If you have a male plant, it can fertilize the other female plants, and they will work to produce seeds instead of flowers and nugs.

It’s essential as a grower to know the difference between a female and a male plant so that you can remove the male plants before they contaminate your crop . Unfortunately, you have a 50/50 chance of getting a male plant when growing a plant from a seed from a nug.

There is a massive market for seeds that will only grow into female plants. But even these seeds are not a 100% guarantee you’re going to get a female plant. To ensure a good crop, you’ll want to germinate and plant many marijuana seeds and then separate the females from the males when the plants begin to show their sexuality.

How to Tell if a Weed Seed is Male or Female

As your plant matures sexually, it will develop between its nodes. Nodes are the area of the plant where the branches connect to the plant’s stalk. The distinguishing characteristics that will help you identify your plant’s gender:

  • Male Plants : Small pollen sacs will cluster in the nodes.
  • Female Plants : Stigmas will develop in the nodes. The stigmas can catch the pollen of male plants. Stigmas have hair-like veins that will extend from the sacs in the nodes.
  • Hermaphrodite Plants : These plants have both the stigmas and pollen sacs in their nodes. These are female plants that develop both sex organs when exposed to a lot of stress.

Once you can identify the sex of your plants, you’ll want to remove the male or hermaphrodite plants because they can negatively affect the harvest of your female plants. That’s why it is crucial to germinate and grow several cannabis plants to this stage to ensure you get at least one healthy female plant.

9) Grow Weed Plant, Grow!

Suddenly, before your very eyes, the plant will transform. She will grow in height and branch out, putting off leaves and a network of branches. It is your job as the grower to meet her needs so that she can reach her full potential. With a good grow kit, this means as much light as possible and lightly watering only when she is thirsty.

This is considered your marijuana plant’s vegetive stage. The goal in this stage is to keep her healthy and allow the plant to grow as big and strong as possible so that she can hold many, many flowers.

Our complete grow kits include everything you need to go from seed to your very own supply of high grade medical cannabis.

How to grow cannabis indoors

Growing cannabis indoors allows the grower to optimise lighting, temperature, humidity, air flow, nutrients and other key environmental factors. Indoor cannabis growing also allows you to control pests, something that the outdoor grower can’t always guarantee. The result is that well grown indoor cannabis can reach the very highest quality levels. No wonder that millions choose to grow weed indoors with the finest cannabis seeds and best grow room conditions. Whether you are a beginner aiming to start the right way or a skilled grower searching for the best ways to optimise the quality of your crops, this essential indoor cannabis cultivation guide is a keeper!

What are the key benefits of cultivating cannabis indoors?
How to plan your indoor cannabis grow from seed to harvest
What is the best initial setup and equipment needed?
What is the ideal space to grow cannabis indoors?
How to choose the best cannabis seeds for indoors
How to set up your indoor cannabis grow room
Indoor cannabis plants feeding schedule

Indoor cannabis cultivation benefits

Outdoor/greenhouse cannabis growing has plenty of pros but a few occasional challenges such as cloudy/stormy weather, cool conditions, pests and other risks. Indoor cannabis growing may be more expensive due to electricity prices and the purchase costs of the tent, LED, fan, filter etc.

That being said, a high quality and well thought-out indoor grow room allows the grower to push every last bit of genetic potential from their cannabis seeds by optimising all the conditions and removing any limiting factors which might limit growth.

Get your indoor grow conditions right and you can look forward to the best possible quality levels with a terpene profile that will make you gasp in delight and cannabinoids that will refresh your soul with memorable pleasure.

Whether you prefer growing with autoflowering cannabis seeds or feminised seeds, the ultimate goal is to produce a harvest of the finest possible quality. An indoor grow room/tent fitted with a solid LED, good genetics and a skilled grower has every reason to shoot for buds with 20-25% THC levels. Street weed and coffeeshop cannabis average around 15% THC. Serious growers know that growing their own cannabis is the best way to guarantee top quality buds for the minimum price.

So long as you’re not trying to grow cannabis in your attic/loft during a heatwave, an indoor grow generally allows you the maximum control over the grow environment. This is especially true for the grower who has carefully planned the location of their grow room and invested in the necessary equipment to produce optimised conditions. This may include a quality LED light and an extraction fan that is able to adjust speed/power as required to maintain temperatures and humidity in the sweet spot. Grow with slow release organic nutrients (avoiding the risks of under/over feeding with bottled nutrients) and you won’t necessarily need years of experience to grow connoisseur quality buds.

Growing cannabis indoors allows you the chance of multiple harvests each year. Unlike the outdoor grower who has to work within the limits of their grow season the indoor grower can grow all year round. Basements and bedrooms tend to be popular indoor grow room locations with many preferring to grow in a modern grow tent. Rooms that are prone to temperature extremes (e.g. lofts) are less favoured since they can be unusable in mid-winter and mid-summer.

Growing cannabis indoors does come with a small risk risks of pests. But with a few sensible precautions and a quick response (if pests are seen) the indoor grower should be able to get on top of any pest issues quickly. Use of predator insects is an increasingly popular (and chemical-free) way of dealing with indoor cannabis pests. Some growers pro-actively release predator insects whether required or not, the costs are low and there are no downsides.

Some outdoor growers feel nervous about growing cannabis in greenhouses or the great outdoors. Growing indoors allows you a completely private hobby, no-one other than you need know about it. A useful tip is to ensure you always have a working carbon filter and a spare one – one day you will need it!

Indoor growing allows you a safe and secure location for indoor cultivation. Those concerned about security can install indoor/outdoor CCTV, improved outdoor lighting and other measures.

When planned and executed well, growing cannabis indoors allows you complete control over all key cultivation parameters. Avoid over watering, avoid over-feeding, get a stable grow room, a quality LED light with good cannabis seeds and you should get top quality results.

Indoor cannabis growing stage by stage

Watching your cannabis seeds germinate and grow into mature female plants is a great joy and source of satisfaction. Many cannabis growers enjoy the experience of growing just as much as they enjoy the harvest! Growing cannabis indoors is often more than just a way to be self-sufficient in premium quality, low-cost buds. It’s an absorbing and rewarding hobby in which continual improvement & learning provides great fulfilment.

Photoperiod feminised seeds remain the preferred choice for many. Once germinated, the seed transitions through several different stages of life before harvest, typically 3-4 months later.

Less experienced growers may prefer the simplicity, speed, convenience and wide-growing latitude of autoflowering cannabis seeds. Autos typically grow from seed to harvest in around 11 weeks, thats often a few weeks faster than photoperiod feminised seeds.

Old school growers often enjoy the experience of growing regular cannabis seeds, selecting male and female offspring for further growing/crossing.

Many cannabis seeds germinate in 2-3 days, most do so in 3-5 days but some can take as long as 1-2 weeks.

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Serious growers don’t mind paying upwards of €/$/£100 for a pack of 10 cannabis seeds so long as the genetics have been expertly bred and produce pro-results. So it makes sense to shoot for 100% germination rates. Use the damp cotton pad method for best results. One important tip is to cool-store your cannabis seeds in the fridge for maximum longevity.

Often regarded as the first week or so following cannabis seed germination.

Typically around a month when growing autoflower seeds (and a maximum of 2 months), this exact time is determined by the cannabis genetics. The grower determines the length of vegetive growth with photoperiod feminised seeds.

With low/moderate light levels required in the vegetative stage, growth will seem initially slow and will pick up pace as the plants age and increase in size.

When growing photoperiod feminised cannabis seeds most growers tend to grow their plants under 18-24 hours of daily light for around 4-6 weeks.

Longer periods of veg growth favour larger final plant sizes and heavier yields. Often growers prefer to grow with a blue-dominant light spectrum for best results in veg growth. This is possible with colour-adjustable LED grow lights, though some growers use e.g. blue-spectrum ceramic metal halide lights.

During the vegetive growth stage some growers like to consider the use of high stress training and/or low stress training to prepare the plants for heavier final yields.

Growing cannabis indoors requires intense light with a heavy red content in the spectrum during bloom. Light intensities are steadily increased as bloom progresses, with maximum light levels reached in the last few weeks before harvest.

Ensure that your LED light, carbon filter and fan are appropriately matched to the size of your grow room. Research your choice of cannabis seed supplier and your preferred genetics well.

Grow tents with less vertical growth space may be better suited to shorter indica/indica dominant cannabis strains or those that prefer growing with the SCROG method. Taller grow rooms may find it easier to accommodate taller, stretchier sativa strains.

Some growers find that growing a small number of large plants with the SCROG method gives best results for them. This often suits the slightly more experienced grower. The less experienced growers may find that growing/flowering cannabis plants in the natural way, without training, is easier.

As your plant approaches harvest the indoor grower has time to consider how ripe they want their harvest. If you’re not sure, you may want to collect buds at the normal harvest point and compare them to buds that were harvested early and late. Your preference may influence when you time the harvest of a future crop. When growing your own cannabis indoors, it’s up to you to select the perfect moment of ripeness that suits you!

Not all growers believe in the principle of flushing cannabis – the process of ‘feeding’ with just pure water for the last week or two in an attempt to create a better/purer tasting result. But many growers remain firm believers in flushing despite claims that flushing has no beneficial effects.

Find out what you prefer and do all you can to tailor your harvests for your precise personal taste. Getting your harvest right is crucial, you have worked hard for months with the best cannabis seeds and equipment. Make sure that nothing can spoil the timing and result of your harvest.

Note that allowing an extra week or two at the end of bloom can give you a heavier harvest and a more powerful, sedating effect. One privilege of growing cannabis indoors is that you can allow your plants to ripen fully, free from commercial pressures to chop early and start the next crop. Take your time – enjoy, learn and improve with each crop.

For many growers, the last week or two of growth is perhaps the most enjoyable and rewarding part of the grow. Monitor your plants well, check trichome appearance (clear/milky/amber) and harvest when the effects are perfect for you. Take your time to cure the buds well and look forward to cannabis quality levels that far exceed anything you can buy.

Indoor cannabis initial setup and equipment

When growing cannabis indoors many self-sufficient growers opt for a grow tent around 1.2m x 1.2m (4ft x 4ft) and will match the fan, filter and light to that sized tent. An indoor grow room complete with quality LED, fan, filter etc will set you back around €/$/£1000 or more.

That can seem excessive for some, who opt for cheaper systems with HPS lights and budget fan/filter combos. If funds are initially limited, you can always progressively upgrade your grow room as your passion and experience improve. Indeed, continuous grow room improvement/investments is precisely what many growers love to do.

One final thought, spending €/$/£1000 or more setting up a new grow room with an LED may seem expensive, but the costs are likely to be repaid from the value of the first harvest.

Micro-growing is possible in spaces as small as 60cm x 60cm but is unlikely to meet the bud needs of a daily cannabis lover. Work out how much space you can use for your grow area and do your best to maximise the productive use from this space. Many growers tend to opt for larger grow spaces once they realise how much fun they are having.

HPS will do a job for a budget price but all serious growers prefer LED. With inherently lower heat levels of heat stress, longer life and an optimised light spectrum LED automatically delivers higher cannabinoid and terpene levels.

A basic budget fan may not have adjustable speed and can be noisy. More sophisticated options have a near-silent operation and can vary their output according to grow room temperature/demands.

This is another area where spending a little extra can deliver significantly extra peace of mind. Budget filters may only last a grow or two. More expensive professional carbon filters can last a year or two. It’s worth noting that one of the biggest contributors to failed grows, especially when growing in ‘illegal’ countries, is when the grower fails to control grow room aroma.

When growing cannabis indoors it can pay in the long-term to equip yourself with the best available equipment. This can save cash on inevitable future upgrades. Many growers often like to increase the size of their grow tent once they realise how much satisfaction they get from the process of growing their own cannabis – something to consider when deciding the initial grow room set up.

What is the ideal space to grow cannabis indoors?

Many growers have limited options when it comes to growing cannabis indoors. Often bedrooms are used, with the exhausted air vented indoors (not ideal, but often done).

If you do have options it pays to choose a room which doesn’t see large temperature variations and doesn’t suffer humidity issues. The following considerations are worth contemplating when choosing the best place for your indoor cannabis grow.

Attics are often used for indoor cannabis growing in spring and autumn/fall when temperatures are not hitting the extremes seen in mid-summer and mid-winter. Remember that large temperature fluctuations cause plant stress which limit potency/quality. Two of the biggest difficulties for attic growers are extreme summer heat and low winter temperatures.

Steady year-round temperatures are often one benefit of growing in the basement. This allows you to grow in any season. If your basement is damp this can cause increased risk of mold/bud rot especially in late bloom. Basement growers often select high-powered extraction fans which can move the extracted air vertically upwards a storey/floor or two to be extracted e.g. from a roof vent/chimney.

If you have an existing spare room or closet you may not need a grow tent. Growing cannabis indoors can be done in small cupboards. Some DIY skills may be required to accommodate air extraction etc.

Garages can be a convenient place to grow so long as winter temperatures don’t drop too low. Garage growing also allows the DIY enthusiast the option to disguise the grow area behind a false wall made from e.g. plasterboard. As with all indoor grows, efforts need to be made to scrub extracted air of all smells… just in case.

An off-the-shelf grow tent or grow box is a fast, easy and convenient way to create your indoor grow space. They come in a vast range of sizes in varying quality levels. What’s more, if required you can strip down a grow tent and dismantle your grow room in an hour or two in an emergency.

Those confident in their own DIY skills (or the DIY talents of a close friend) can build their own room often with stud walls to the required size. Some people go to elaborate lengths to create disguised entrances, hidden doors or crawl tunnels for maximum peace of mind.

Choose the best area you can for your indoor grow location recognising any restrictions or limitations that may place on your grows. Loft growers may not be able to grow all year round, for example.

How much space do I need when growing cannabis indoors?
1.2m x 1.2m / 4ft x 4ft tends to be typical for many self-sufficient home growers. This can allow space for 4-5 large plants and approximate yields around 400-600g depending of course on many factors including light, cannabis seeds, length of veg time, grower experience etc.

Choosing the best cannabis seeds for indoors

Cannabis genetics play a huge role in determining the quality of your harvest. Even the best equipped grow room in the world won’t be able to deliver high THC results from low-end cannabis seeds.

You may spend around 3 months, or more, growing your seeds. Therefore, don’t be afraid to spend the necessary time contemplating the various options available to you. Competent cannabis seed suppliers should offer you detailed expectations of likely potency levels, plant size, yield and effects.

Photoperiod feminised cannabis seeds grow in veg mode until daily light hours are reduced to around 12. This allows the grower the chance to determine how long (and how large) to grow the plant. In vegetive growth (typically 18-24 daily light hours) the plant produces roots, branches and leaves but no buds. Many growers, including those specialising in SCROG growing find feminised seeds allow maximum control over the precise moment to initiate bloom.

Autoflowering cannabis seeds grow from seed to harvest, typically under 20 hours of daily light in around 10-11 weeks. Some strains such as Auto Blueberry and Auto Blackberry Kush can complete the growth cycle in as little as 8-9 weeks. Others such as Auto Ultimate can take 12-15 weeks with correspondingly higher yields. Many growers prefer the speed and simplicity that comes when growing autoflower seeds, especially those from the top-tier cannabis seed suppliers that take the time to fully stabilise the genetics, optimising potency and yield.

Indica and indica-dominant cannabis seeds often give rise to short, squat plants with broad-fingered leaves. Conversely, sativa & sativa dominant seeds often tend to produce stretchy, tall plants with greater internodal spacing than indica plants.

The amount of available head-room in your grow tent/grow room could affect your choice of indica vs sativa cannabis seeds. Likewise, your preferred grow method could also determine the type of strains you grow. For example, SCROG growers may prefer strains that can easily be bent/worked into a SCROG screen. Not all strains are suitable for all grow rooms and methods, so research carefully and ensure you get accurate genetic descriptions from your cannabis seed supplier.

Many growers enjoy the variety that comes from growing multiple cannabis strains together. However that can bring certain challenges, for example if the strains grow to different heights. Use of low stress training (LST) and high stress training (HST) techniques can allow you to maintain a level canopy of buds all within the optical sweet-spot of your grow light.

Growers keen to enjoy a multi-strain harvest shouldn’t feel daunted by the challenges, especially those with a little experience in plant training/topping techniques. Lots of home growers appreciate the extra variety in the jars that comes from planting cannabis seeds from different strains.

Regardless of your preferences, always select cannabis seeds based on your situation and requirements. Smart growers often look at online grow reviews as part of their research before making their final choice. Experienced growers can find that plant training techniques (low/high stress training) can greatly improve productivity and yield.

How to set up an indoor cannabis grow room

If you’re upgrading your grow room, or setting one up for the first time, you may feel a little overwhelmed with the endless array of options. A knowledgable local grow shop owner is often a great source of advice. Some online grow shops also offer solid advice.

In general, less experienced growers may find it easier to initially opt for simpler options. Beginners may find it considerably easier to grow their cannabis seeds in large-aerated containers of soil with slow-release organic nutrients (e.g. BioTabs) rather than attempting a hydroponic SCROG.

Research your options carefully, recognising the strengths and limits of your own experience/situation and remember you can always upgrade your grow room (and grow style) as your confidence and experience evolves.

1. Choose the best-suited growing containers

Cannabis seeds can be grown in most types of grow container so long as the basics are present i.e. nutritious moist soil. But experienced growers have known for some time that those containers that offer maximised levels of root aeration tend to produce the healthiest root zones and therefore the largest plant with heavy yields.

Many professional cannabis growers, alongside serious self-sufficient growers, feel they get superior harvest quality/quantities when using aerated grow containers such as air pots, felt sacks or similar. These allow great levels of root oxygenation that standard non-aerated containers. Cannabis roots need oxygen to survive and thrive. By increasing oxygen levels in the cannabis root zone healthier, stronger growth is achieved.

Even when growing in a highly aerated grow medium such as a light-soil mix or coco fibre, root aeration and overall growth rates are benefitted by the use of an aerated grow container. Some growers push root aeration to the max, for example growing cannabis in coco fibre/air pot in combination with an air-stone at the bottom of the air pot.

When growing cannabis give serious attention to the use of grow containers that allow extra levels of root aeration (air pots, felt sacks etc). By allowing extra levels of root oxygenation increased growth/health of the cannabis root system will result. You can expect larger, healthier cannabis plants with heavier harvests and perhaps more potent buds.

2. Define a watering system

A plant as flexible as cannabis can be grown with numerous different grow methods and watering systems. Which grow method best suits you will depend on a few factors.

How much complexity are you prepared to tolerate? How much automation do you want/need? How large is your budget? In general less experienced growers are advised to keep the watering system as simple as possible initially. Watering your plants manually is one of the more common methods, but there are a range of systems to suit all needs and budgets.

Perhaps the two most common errors seen when growing cannabis are the tendencies to over water and over feed. These errors are especially common among less experienced growers who may apply the (incorrect) logic that more water/food will produce larger plants.

The opposite is true, too much water will cause the cannabis roots to sit in an oxygen-deficient environment where they will eventually rot. Too many nutrients will burn the cannabis roots, permanently limiting future growth. Whichever grow system/medium you use, be sure to do all you can to keep your plants in the nutrient sweet spot, with neither under feeding nor over feeding.

Cannabis hydroponics is the method of cultivation without soil. Various hydroponic grow methods have been created and all work well. So long as the cannabis roots are supplied with essential minerals, moisture and oxygen they should thrive and support fast plant growth, even without the presence of soil. Fans of cannabis hydroponics claim it is the fastest way to grow cannabis, outstripping growth rates in e.g. soil or coco fibre.

One common feature of hydroponic systems is a focus on ensuring that the cannabis roots get sufficient oxygen, despite the often wet/submerged conditions. Although all different hydroponic systems may have slightly different, soil-free designs, they all incorporate the principle of allowing oxygen direct access to the roots. Here are some of the more popular cannabis hydroponics options.

Note that these methods tend to suit the more experienced cannabis grower who is able to measure pH (a measure of acidity) and E.C. (electrical conductivity, a measure of the mineral content in a solution). Use of pH and E.C. meters require the grower to be able to correctly calibrate, read and maintain their meters.

Cannabis aeroponics works by suspending the roots in an oxygen-rich mist of water droplets. The water droplets contain the traditional nutrients and minerals to nourish the plant. Not recommended for beginners, aeroponics tends to suit the more experienced hydroponic grower capable of managing the various technical demands.

Claimed by many cannabis hydroponics fans as the fastest way to grow weed. The cannabis roots grow downwards from a net into a bucket of water/nutrients. Normally you might expect the roots are to rot when growing in a e.g. 25 litre bucket of water. But the presence of a powerful air stone at the bottom of the bucket (connect to an air pump) bathes the roots in a constant flow of oxygen-rich bubbles.

A cannabis dripper system often grows the cannabis plant in an inert grow medium such as clay pebbles. A small pump forces the nutrient solution up from underneath the roots and drips it into your chosen grow medium. The roots have open access to oxygen and are fed by a gentle stream of nutrient drops. As with all hydroponic grow methods the grower needs to check nutrient concentrations regularly and refresh the nutrient reservoir on a regular basis.

The ebb & flow hydroponics method regularly floods your grow containers with nutrient solution to allow them to feed. After a specified time the fluid is drained away allowing the roots access to oxygen before the process is repeated. A grow medium such as clay pebbles, glass wool, coco fibre etc is often used.

With the cannabis nutrient film technique (also known as ‘NFT’) minerals/nutrients are pumped from the reservoir onto a thin absorbent mat. The cannabis roots grow in and around this mat eventually forming a thick layer of roots as they absorb the required nutrition. Because the roots are not completely immersed in liquid they have access to atmospheric oxygen and grow rapidly.

A wick system is a passive hydroponics method that sucks up liquid to the root zone using a wick rather than a pump. Various versions of the wick system exist, often based around a grow medium of coco fibre, perlite, vermiculite etc. The grow medium has a wick, e.g. an absorbent length of rope, twine etc dipped into a lower nutrient reservoir. The wick transports liquid from the reservoir to the grow medium via capillary action.

Cannabis hydroponics produces very fast growth. As with every other cannabis grow method, best results are achieved when the cannabis plant is maintained in the nutrient sweet spot, with neither over feeding nor under feeding. This produces the stress-free conditions in which the plant can grow quickly and thrive – assuming all other growth factors (light, temperature etc) are also fully controlled and optimised.

3. Simulate the desired climate

No matter how good your cannabis grow system, you won’t get the best results unless you can create optimised conditions in which to grow your cannabis. This means getting temperatures, humidity levels etc optimised at each stage of growth. Remember the conditions required for your plants will vary greatly as she transitions from cannabis seed to harvest-ready female.

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Germination is often regarded to be the time taken from planting the cannabis seed to the stage where it has produced it’s first cotyledon leaf pair. These are the initial (non-serrated) leaf set which is formed at cannabis seed germination. Germination often takes from 2-10 days in dark conditions, no nutrients are required.

Cannabis seedlings require mild conditions, light levels can be quite low at the start but need to be increased as the seedling becomes older to reduce stretching. Nutrition, if required at all, is at very low levels in order to avoid permanently damaging the delicate root network.

High humidity levels can be tolerated by seedlings and may even be useful (e.g. for cuttings) until the root network is fully developed. Temperatures of around 20-25ºC (around 70ºF-77ºF) give good results for cannabis cultivation, from germination to bloom. During the seedling stage (or when rooting cuttings) high humidity levels of around 65-70% can be used. Early root development may be slow, a humid environment may be useful to ensure the seedlings have sufficient moisture until the roots are fully established.

During cannabis vegetative growth your plant will produce roots, leaves and branches but no buds. When growing autoflowering cannabis seeds the genetics determine the length of the veg cycle.

When growing photoperiod feminised seeds the grower determines the length of the veg cycle – plants are forced into bloom when daily light hours are cut from around 20 to around 12. For vegetative stages humidity is usually kept around 60-75%. For clones that have not rooted yet keep humidity very high, about 85-90%, best way to do this is by using a dome (mini plastic greenhouse). Temperatures around 23ºC (75ºF) are good for veg growth.

Bloom begins ‘automatically’ at a time of the genetics choosing when growing autoflower strains. For photoperiod feminised strains bloom begins when daily light hours are cut to 12. Hormonal changes associated with bloom in the cannabis plant biochemistry forces the production of female flowers, complete with lashings of resin in a process that often takes around 9 weeks. Good air circulation is important. During bloom it is important to ensure humidity is kept as low as possible, below 50% is preferred. This minimises the risk of bud rot/botrytis in dense blooms, often a worry for growers in high humidity conditions.

Most indoor growers aim for a steady temperature of around 24ºC/75ºF when their lights are on and perhaps a couple of degrees cooler when the lights are off. But during bloom, some growers deliberately drop the ‘night time’ minimum temperatures to induce some autumnal hues in the buds, increasing the eventual jar-appeal.

The cannabis flowering stage is critical to the eventual harvest quality and quantity. Master the conditions required and you can look forward to connoisseur quality buds! The following expert guide is packed with pro tips to follow and explains the man pitfalls to avoid.

Ensuring an optimised, stable indoor grow climate for your plants is often one of the most overlooked areas of indoor growing. Pro-growers go to great lengths, often with adjustable extraction fans that keep grow room temperatures as stable as they can. Avoiding extreme heat/cold allows you to maximise THC levels and final bud quality.

4. Provide optimal lighting to your plants

Cannabis requires high light levels during bloom to allow the cannabis genetics to reach their full potential. Even high quality cannabis seeds will produce puny harvests and small buds when grown with inadequate light intensities. Choosing the right cannabis lights for your grow area and knowing how to use them correctly is one of the most crucial aspects of indoor cannabis growing.

Unfortunately there is a massive range of grow light technologies with prices from budget levels all the way up to professional grade LED. When it comes to the potentially expensive time to buy/upgrade your grow light it really is worth taking your time and considering the options carefully.

How to calculate your lighting needs?

Your grow light, especially if you opt for LED (the choice of most serious/pro growers) will probably be the most expensive part of your indoor grow room. Some growers are tempted to save cash and use a slightly underpowered light, but this is false economy since harvest amounts will be reduced.

When growing cannabis indoors many use a 1.2m x 1.2m (4ft x 4ft) tent. Often a 400-650W LED will be used, or perhaps a 600W HPS if a budget option is required. This will allow PPFD light levels of around 750-1000 μmol/m2/s which will allow optimised bloom. Professional grow light manufacturers will list the recommended hanging heights for their light at various stages of growth. They should also clearly explain the PPFD light intensities in grow tents of different sizes.

Best types of grow lights for cannabis

Here are the main light choices for growing cannabis indoors.

The most expensive option, an LED of typical power (around 400-650W for a 1.2 x 1.2m tent) will often cost in the region of €/$/£750-1000. With minimal levels of heat stress, an optimised spectrum and a 10+ year lifespan LED’s deliver proven higher cannabinoid and terpene levels than HPS.

Compact fluorescent lights are often used for germination or seedlings. The gentle, soft light levels are ideal for the lesser lighting needs of smaller plants. They are generally not used as much for bloom.

The most popular budget option, 600W HPS lights (suited to a typical home grow tent) are available from €/$/£100 or less. But the performance and results won’t match an LED. HPS bulbs need replacing after every couple of grows, they emit large amounts of heat and don’t benefit from the same fine-tuned light spectrum.

Ceramic metal halide lights are often regarded as superior to HPS. They have become popular in the last few years, though many feel that CMH lights lack the excellent performance of the best LEDs.

Many pro-growers like to add extra UV light to their grow room to mimic the effects of the sun. UVB in particular is thought to encourage higher THC levels and extra resin production. UVA is thought to increase terpene levels in the cannabis buds. One bonus side effect of UV light is that it can reduce/eliminate flying pests such as fungus gnats (often found in soils containing wood).

Mounting your light fixtures

You have researched your light options carefully and maxed out your budget to get the best grow light you can afford. Now you need to make sure that the light is mounted correctly. Ensure that your light is hung level, some growers use a spirit level to ensure the light is level and illuminating the grow area evenly.

You also need to hang the light at the right height above the canopy. Your grow light manufacturer should give detailed hanging heights and (if necessary) the associated power levels.

Monitoring and adjusting your lighting

Many grow lights, especially modern LED lights, come with adjustable lighting. This allows the grower to slightly adjust/increase their grow light power as their plants mature. Few growers have a light meter that allows them to measure PPFD, instead they rely on their experience and the light manufacturers recommendations.

If you can afford it, LED is the preferred option for growing cannabis indoors. An LED grow light will function for thousands of hours with negligible intensity loss. Remember to get a light that will allow your grow room area to reach PPFD levels of around 750 (or perhaps more) to maximise bloom potential.

5. Achieve an optimal grow room air flow

Oxygen and Carbon Dioxide are two essential ingredients for the growth of cannabis. Ensuring a good air flow through your tent is another of the often overlooked aspects when growing cannabis indoors. Not only does all the air in your grow room need to be replaced perhaps 2-3 times every minute, but you will need circulation fans inside your tent to ensure no ‘dead spots’ of stale air.

Air in your grow room tends to get hotter and more humid, removing this and replacing it with fresh air allows your plants to grow in a healthier environment.

Mold/bud rot can be real threats when humidity levels are allowed to creep upwards during bloom. Once your plant is stressed fighting disease or environmental irregularities (e.g. plants drying out almost completely) it can be more prone to attacks from pests.

Supplemental CO2 can be used to increase growth rates but this only really makes sense for professional growers who have fully maxed out their light intensity levels. Many ‘CO2 generators’ are used when growing cannabis indoors. The simplest ones are bags containing mycelium which emit a steady stream of CO2. CO2 can also help growers that are battling high temperatures, plants seem to thrive more in higher temperatures when they have higher CO2 levels.

Ensuring your plants have good nutrition, lighting and a good grow room environment will allow them to grow into strong plants, resistant to health issues. Some growers also like to offer nutritional tea/vitamin supplements to their plants.

Indoor cannabis grow room ventilation

Many home growers like to keep a spare carbon filter at home for the inevitable day when they notice their existing filter is starting to fail. For extra security some growers will position an ozone generator in the exhaust air stream. The ozone chemically removes any traces of cannabis aroma that managed to escape the carbon filter. As well as ensuring a good flow of fresh air into the grow room (to optimise plant health and minimise chances of disease) growers need to ensure that the exhaust air is scrubbed clean of any cannabis aromas.

Indoor cannabis grow room air circulation

Small clip-on fans are often used by growers to ensure that no pockets of stale air can remain in the grow room. These can also be positioned underneath the plant canopy, an area often neglected by indoor growers. Likewise, any dead foliage, fallen leaves, dirt etc should also be cleaned away. A little extra effort to ensure good grow room circulation can avoid problems later on.

Indoor cannabis grow room CO2 supply

Hobby growers probably needn’t worry too much about supplementing grow room CO2. It only really makes sense to introduce extra CO2 when the grower has eliminated every other bottleneck restricting growth. Often CO2 is used when grow room PPFD (light intensity) levels are at/above 1000

Most growers probably won’t need to worry too much about introducing extra CO2 when growing cannabis indoors. However some licensed/pro growers may find it cost effective.

There is little purpose in buying the best cannabis seeds, LED grow light etc if your grow room suffers from poor air flow and/or poor circulation. Ensure an adequately sized extraction fan and a matching filter. Self-adjusting extraction fans that maintain grow room temperatures are often preferred by pro-growers.

6. Maintain a clean and safe environment

Keeping a clean and safe grow area takes very little effort at all, especially if the grower keeps on top of the grow room with basic housekeeping/tidying. Not only is it good growing practice to ensure a tidy tent when growing cannabis indoors, it can prevent pests/disease outbreaks saving the grower from future problems.

Cleanliness and safety measures

Never allow dead leaves and soil/nutrient/grow-medium mess in your grow room. Dead leaves/vegetation can allow disease (or pests) to take hold.

When growing cannabis indoors, problem prevention is always better than problem curing. Modern grow tents have wipe-clean surfaces allowing you to clean the mess up and wipe down the surfaces. A small hand-held vacuum is perfect for hoovering up any soil/coco-fibre dust.

Indoor cannabis odour control

Especially in countries where growing cannabis indoors is still illegal, growers need to take extra care to deal with any cannabis aromas. If not they risk broadcasting the presence of their grow room. Use of good quality carbon filters (and stocking a spare one at home, just in case) is always recommended.

If a grower can keep a clean, well organised grow room they can avoid problems later and allow a pristine grow environment where they can grow the highest quality cannabis indoors. Ensuring your grow room has good odour management in place ensures maximum peace-of-mind

7. Soil and other media for growing weed indoors

Many people find soil is a simple, easy grow medium when growing weed indoors. Use a large enough volume of it (especially in conjunction with slow-release organic nutrients such as those from BioTabs) and you needn’t worry too much about needing to add mineral nutrients throughout the grow.

Plenty of other growers find coco fibre easy to grow in – perhaps with slightly faster plant growth compared to soil. But other options are available too, such as growing in fibre glass, rock wool (and mapito) clay pebbles, perlite etc.

Growing cannabis in soil is an easy way to get great results when growing cannabis indoors, whether you are an experienced grower or just starting. Many growers also claim that the richest cannabis taste comes from organic, soil-grown weed.

The best type of soil for indoor cannabis

A good quality soil is light, aerated and contains the necessary nutrients and minerals to sustain plant growth. Often growers have their preferred soil blend from their local (or online) grow shop.

Numerous soil brands are available, some lighter options more suited to seedlings and fortified soil blends suitable for more mature plants. Some wood-free soil mixes claim to be free from pests such as fungus gnats and are popular with many growers.

All good quality pre-prepared grow shop soils should have a light fluffy texture, not too dense/heavy. The main brands all deliver good results when growing cannabis indoors.

The larger the grow container the greater the volume of soil your plant has. At the same time, large grow containers offer a large reservoir of nutrients which may sustain the plant into late bloom necessitating perhaps only a light top-dressing of bloom nutrients as the plant approaches harvest.

Many growers like to combine a reputable, good quality soil brand with an aerated modern grow container such as an air pot or grow sack. It’s not uncommon for containers of 50 litres+ to be used when growing weed indoors. Large, aerated grow containers favour the extensive root network necessary for growing the largest plants, often with minimal plant maintenance.

Aim for a large, aerated grow container (aim for 50-75 litres + if you have the space) of soil and supplement the soil with BioTabs slow release grow nutrients for an easy, uncomplicated grow experience. You will need to add little else (if anything) other than water until the end of the grow.

Growing cannabis indoors with coco fibre

Growing weed indoors using coco fibre has become very popular. Many adepts claim faster growth rates than those seen in soil, though not as fast as hydroponically grown cannabis. Coco growing usually requires a basic mineral nutrient mix made from a simple ‘Part-A’ & ‘Part-B’ nutrient blend.

As with soil, numerous reputable coco fibre brands are available. It is always recommended, especially for less experienced growers, to buy the more expensive washed/buffered coco fibre. Dutch Passion also recommend the use of slow release organic nutrients, e.g. BioTabs, with coco fibre which simplify the nutrient considerations even further.

Indoor cannabis nutrient feeding schedule

Use of nutrients is one area that can cause difficulties, and even disasters, for growers. Fail to provide enough nutrients and your plant will be unable to grow adequately and may show nutrient deficiencies. Growing cannabis indoors with an accidentally excessive nutrient regime is an even more serious problem, in the worst cases the plants will be permanently stunted or will die.

The holy grail of nutrient management is to understand the plants nutritional needs at each stage of growth and meet them without over-feeding or under-feeding. The goal is to maintain your plants in the nutrient sweet-spot from the germination of your cannabis seeds all the way though to harvest. This is easier said than done, experience plays a large part. It pays to start with low nutrient levels and slowly increase, backing off at the first hint of nutrient burn.

It’s also important to use reliable pH and EC meters, calibrate them regularly and have replacement meters ready for the inevitable day when the meter starts to fail and give erroneous readings.

Use of bottled mineral nutrients does require care and precision. Get things badly wrong and you could wipe out your crop quickly, especially if you are growing with hydroponics where the impact is immediate. Experienced growers tend to feel less daunted with the task of managing an array of specialist nutrients. Rookie growers often feel understandably cautious when it comes to bottled nutrients and many prefer the simplicity and fool-proof nature of slow release organics instead (BioTabs) which allow the grower to simply add water to their plants for much/all of the grow.

Complete confidence with nutrients/nutrient feeding schedules comes with experience. Get things badly wrong and you can damage your crop. Less experienced growers seeking an easy way to keep their plants in the nutrient sweet spot may wish to consider slow release organic nutrients in large aerated containers of soil.

Grow your premium indoor weed at home!

Growing cannabis indoors at home allows you to enjoy premium quality buds at a fraction of the normal price. Most home growers would say that they can grow better quality buds than they can buy.

You can choose the genetics, grow them to their maximum potential with a solid LED light and harvest the plants at the point of your choosing. The grow process can be as complicated and hands-on as you wish. Or it can be a simple, easy process where you need do little else other than water your plants. It all depends on how you want to grow and how much control you want to take.

One of the easiest ways to grow cannabis indoors is in large aerated grow sacks of soil with slow release organic nutrients. There really is little to go wrong with this method!

However you grow, do your best to learn as much as you can along the way and try to incorporate continuous improvements to your grow room. Growing cannabis indoors is not just an affordable way to supply yourself with premium buds, it’s also great fun and an enjoyable hobby for millions of people around the world.

10 Comments . Leave new

How close to put growing LED lights

It depends on the type/power of LED light you have, if its powerful start at 65cm for veg and bring it down to 45cm for flowering.

More Blue light increases the number of female plants ?

We have not worked with this technique yet, but there are indeed theories out there that blue light in the vegetative phase could increase your numbers in female offspring.

Dutch Joe

There is some excellent advice in this article. Dutch Passion has been producing world class genetics for decades. Whether you are growing indoor or outdoor, Dutch Passion will have seeds to fit your needs =)

where can I find the black and green pot in the header or first image?

This is an airpot, you should check for yourself what the best options are to buy these

Dutch Passion

Is it possible to explain when the veg state stops and the flowering state starts. I suppose the answer is in the question, but I’m a little unsure…?

I am not sure if you mean with autoflowering or photoperiod varieties.

But with photoperiod varieties the flowering period starts when the lights are switched from a 18/6 to a 12/12 light schedule.