Cannabis seeds 101: How to grow marijuana from seed
Cannabis is grown from one of two sources: a seed or a clone. Seeds carry genetic information from two parent plants and can express many different combinations of traits: some from the mother, some from the father, and some traits from both.
In commercial cannabis production, generally, growers will plant many seeds of one strain and choose the best plant. They will then take clones from that individual plant, which allows for consistent genetics for mass production.
If cannabis is legal in your state, you can buy seeds or clones from a local dispensary, or online through various seed banks.
Cannabis seeds vs. clones
For the typical homegrower, it may be easier to obtain cannabis seeds rather than clones. Growing from seed can produce a stronger plant with more solid genetics.
Plants grown from seed can be more hearty as young plants when compared to clones, mainly because seeds have a strong taproot. You can plant seeds directly into an outdoor garden in early spring, even in cool, wet climates.
If growing outside, some growers prefer to germinate seeds inside because they are delicate in the beginning stages of growth. Indoors, you can give weed seedlings supplemental light to help them along, and then transplant them outside when big enough.
Most seeds that you will buy are regular seeds as described above, but here are a couple more types.
How weed seeds work
Cannabis can be either male or female—also called “dioecious”—but only females produce the buds we all know and love. For reproduction, males have pollen sacs and pollinate females, causing female flowers to produce seeds.
Once cannabis seeds are mature, the female plant begins to die, and seeds are either dropped to the ground where they grow into new cannabis plants next spring, or the seeds are harvested for processing into seed oil or food products, or stored so they can be sown in the ground later and become the next generation of plants.
To get the buds found in medical and recreational stores, female cannabis plants are grown in an environment without males—or the males are removed from the area before they release pollen—so the females don’t create seeds. Females can then focus their energies on producing buds and not seeds—this high-potency marijuana is traditionally known as “sinsemilla,” meaning “seedless.”
Some varieties of cannabis can produce male parts alongside female flowers on the same plant, especially if exposed to environmental stressors. These plants are known as hermaphrodites, and sometimes they can self-pollinate to create seeds.
Pros and cons of using cannabis seeds
Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .
If buying from a reputable breeder or seed bank, growing from seed is the best way to ensure your plants will have solid genetics and start clean, meaning they won’t come with diseases or pests.
Also, buying from a reputable breeder or seed bank will give you a sense of what a particular strain will look and smell like, how it will grow, and how much it will yield at harvest.
The main drawback to growing from seed is there is no guarantee as to what you’ll end up with—if you buy a regular pack of cannabis seeds, it will be a mix of males and females. You’ll need to sex them out (more below) to identify the males and get rid of them, because you don’t want your females producing seeds.
Sexing marijuana plants can be a time-consuming process, and if you don’t catch males, there is a risk that even one males can pollinate your entire crop, causing all of your female weed plants to produce seeds.
One way to avoid sexing plants is to buy feminized seeds (more below), which ensures every seed you plant will be a bud-producing female.
You can also minimize headaches and avoid the hassle of seed germination and sexing plants by starting with clones.
How weed clones work
Aside from producing cannabis through seeds, or sexual reproduction, you can also reproduce the plant through cloning, or asexual reproduction. A clone is a cutting that is genetically identical to the plant it was taken from—that plant is known as the “mother.”
Pros and cons of using cannabis clones
Through cloning, you can create a new harvest with exact replicas of your favorite plant. Because genetics are identical, a clone will give you a plant with the same characteristics as the mother, such as flavor, cannabinoid profile, yield, grow time, etc. So if you come across a specific strain or phenotype you really like, you might want to clone it to reproduce more buds that have the same effects and characteristics.
With cloning, you don’t have to get new seeds every time you want to grow another plant—you just take a cutting of the old plant—and you don’t have to germinate seeds or sex them out and get rid of the males.
One drawback of clones is they need to be taken during the vegetative stage of a plant—flower is too late—so if you have a small setup with only one light, it can be hard to keep clones alive while flowering other plants, because the two need different amounts of light.
Another drawback to clones is they can take on negative traits from the mother plant as well. If the mother has a disease, attracts pests, or grows weak branches, its clones will probably have the same issues.
Additionally, every long-time grower will tell you that clones degrade over time.
What are feminized cannabis seeds?
Feminized cannabis seeds will produce only female plants for getting buds, so there is no need to remove males or worry about female plants getting pollinated. Feminized seeds are produced by causing the monoecious condition in a female cannabis plant—the resulting seeds are nearly identical to the self-pollinated female parent, as only one set of genes is present.
This is sometimes referred to as “cloning by seed” and will not produce any male plants. This is achieved through several methods:
- By spraying the plant with a solution of colloidal silver, a liquid containing tiny particles of silver
- Through a method known as rodelization, in which a female plant pushed past maturity can pollinate another female
- Spraying seeds with gibberellic acid, a hormone that triggers germination (this is much less common)
Most experienced or commercial growers will not use feminized seeds because they only contain one set of genes, and these should never be used for breeding purposes. However, a lot of beginning growers start with feminized seeds because they eliminate the worry of having to deal with male plants.
Top feminized cannabis strain families
A lot of classic weed strains that have been around for a while come in feminized form. Some popular fem seeds are:
- OG Kush
- GSC (Cookies)
What are autoflowering cannabis seeds?
Autoflowering seeds are also popular with beginning growers. They are easy to grow because you don’t have to worry about light cycles and how much light a plant receives.
Most cannabis plants begin flowering when the amount of light they receive on a daily basis reduces. Outdoors, this happens when the sun starts setting earlier in the day as the season turns from summer to autumn. Indoor growers can control when a plant flowers by reducing the daily amount of light plants receive from 18 hours to 12 hours.
However, a type of cannabis called Cannabis ruderalis, which developed in extreme northern conditions without much sunlight, will begin flowering once the plant reaches a certain age—they automatically start flowering regardless of the amount of light they receive, hence the name “autoflower.”
Pros and cons of growing autoflower
Because they grow and flower quicker, growers can fit in multiple autoflower cannabis harvests into the span of one regular harvest.
Autoflowers can be started in early spring and will flower during the longest days of summer, taking advantage of high quality light to get bigger yields. Or, if you get a late start in the growing season, you can start autoflowers in May or June and harvest in the fall.
Also, autoflower plants are small—perfect for closet grows or any small grow, or growing outdoors where you don’t want your neighbors to see what you’re up to.
A couple big drawbacks, though: Autoflower strains are known for being less potent. Also, because they are small in stature, they usually don’t produce big yields.
However, potency in autoflowering varieties has increased significantly since their initial introduction, with some breeders crossbreeding the low-THC ruderalis with other more potent varieties.
Tips for growing autoflower marijuana seeds
Autoflowering strains require some preparation, as they will grow quickly and start to flower whether or not you’re ready for them.
Many marijuana growers start autoflowers early in the season, and at a different time than a regular crop, so keep the season and climate in mind when growing and harvesting—your plants still need warmth to grow, and rain can give them bud rot. Consider growing in a greenhouse to protect them.
Because training happens during vegetative growth, for autoflowering plants, this period could be as short as a few weeks, which means time is limited. Try topping your autoflowers after they have three nodes, and stop once they begin to flower. You will want to prune them lightly.
Go easy on nutrients
Autoflowers don’t need lots of nutrients because they’re small and don’t spend much time in the vegetative cycle. They won’t need as much veg nutrients—such as nitrogen—but will need more bloom nutrients.
What are high-CBD cannabis seeds?
CBD, or cannabidiol, is one of the chemical components—known collectively as cannabinoids—found in the cannabis plant. Over the years, humans have selected plants for high-THC content, making cannabis with high levels of CBD rare. The genetic pathways through which THC is synthesized by the plant are different than those for CBD production.
Cannabis used for hemp production has been selected for other traits, including a low THC content, so as to comply with the 2018 Farm Bill. Consequently, many varieties of hemp produce significant quantities of CBD.
As interest in CBD as a medicine has grown, many breeders have crossed high-CBD hemp with cannabis. These strains have little or no THC, 1:1 ratios of THC and CBD, or some have a high-THC content along with significant amounts of CBD (3% or more).
Seeds for these varieties are now widely available online and through dispensaries. It should be noted, however, that any plant grown from these seeds is not guaranteed to produce high levels of CBD, as it takes many years to create a seed line that produces consistent results. A grower looking to produce cannabis with a certain THC to CBD ratio will need to grow from a tested and proven clone or seed.
How to germinate marijuana seeds
Germination is the process in which a seed sprouts and begins to grow into a new plant. Also referred to as “popping,” germination is the very first step in starting your weed grow.
Marijuana seeds can be acquired from an array of sources and can vary in quality. For more info on how to buy marijuana seeds, check out our Guide to buying cannabis seeds.
Cannabis seeds require three things to germinate: water, heat, and air. There are many methods to germinate seeds, but for the most common and simplest method, you will need:
- Two clean plates
- Four paper towels
- Distilled water
Take four sheets of paper towels and soak them with distilled water. The towels should be soaked but shouldn’t have excess water running off.
Take two of the paper towels and place them on a plate. Then, place the marijuana seeds at least an inch apart from each other and cover them with the remaining two water-soaked paper towels.
To create a dark, protected space, take another plate and flip it over to cover the seeds, like a dome.
Make sure the area the seeds are in is warm, somewhere between 70-85°F.
After completing these steps, it’s time to wait. Check the paper towels once a day to make sure they’re still saturated, and if they are losing moisture, apply more water to keep the seeds happy.
Some seeds germinate very rapidly while others can take a while, but generally, seeds should germinate in 3-10 days. If it’s been two weeks and a seed hasn’t sprouted, it’s probably a dud and won’t sprout.
A seed has germinated once the seed splits and a single sprout appears. The sprout is the taproot, which will become the main stem of the plant, and seeing it is a sign of successful germination.
It’s important to keep the delicate seed sterile, so don’t touch the seed or taproot as it begins to split.
Transplanting germinated cannabis seeds
Once you see the taproot, it’s time to transfer your germinated seed into its growing medium, such as soil.
- Fill a 4-inch or one-gallon pot with loose, airy potting soil
- Water the soil before you put the seed in; it should be wet but not drenched
- Poke a hole in the soil with a pen or pencil—the rule of thumb is: make the hole twice as deep as the seed is wide
- Using a pair of tweezers, gently place the seed in the hole with the taproot facing down
- Lightly cover it with soil
Keep a close eye on the temperature and moisture level of the soil to keep the seed happy. It’s very delicate at this stage. Use a spray bottle to water it—over-watering can suffocate and kill the delicate sprout.
Within a week or so you should see a seedling begin to grow from the soil.
Germinating cannabis seeds doesn’t always go as planned. Some seeds will be duds. Others will be slow and take longer to sprout. But some will pop quickly and grow rapidly.
This is the beauty of seeds—often, you can tell which plants or genetics will thrive right from the get-go. This will help you determine which plants you want to take cuttings from for clones or for breeding if you want to create a seed bank of your own.
How to sex a pot plant
Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .
As we’ve mentioned, cannabis is a dioecious plant, meaning male and female reproductive organs appear on different plants.
Because only female cannabis plants produce buds and you want them to focus all their energy on producing buds and not seeds, it’s important to identify and get rid of male weed plants so they don’t pollinate females. If females are pollinated, it will give you buds filled with seeds, making your weed harsh and unpleasant.
Cultivating males is important for breeders trying to cross new strains and genetics, but most people growing for buds will want to remove the males.
As mentioned above, you can skip the processing of sexing weed plants by growing with feminized seeds or clones.
If growing male and female cannabis seeds, they’ll start to show their sex organs, or “pre-flowers,” after 8-10 weeks from germination.
Cannabis plant sex organs appear on nodes, the points where branches grow off from the main stalk.
Males will have round balls—these will develop into pollen sacs, which will release pollen into the air when mature.
Females will have a round structure with long hairs—these hairs will develop into pistils, which will catch pollen in the air.
Pre-flowers can initially be extremely small and hard to identify with the naked eye, but you can use a magnifying glass to get a better look.
Can I grow a seed I found in a bag of weed?
Finding a cannabis seed in your stash is not ideal, but we’ve all been there before. Although much less common than it once was, it still happens. Sometimes you’ll notice one when grinding down some flower, or you’ll see one pop, spark, and crackle from the heat of a lit bowl.
These are referred to as “bagseeds” and whether or not you can grow one will depend on where it came from.
Is a bagseed good or bad?
Seeds found in finished cannabis buds can develop for a number of reasons. For example, a male plant may have accidentally pollinated a flowering female during the growing process. But more commonly, they’re a sign of stress and can be attributed to high temperatures during the final stages of flowering or an exaggerated spike in climate or environment.
Seeds can also form in plants with genetic disorders or instability, like hermaphrodites—plants that develop both male and female reproductive parts. Generally, stress and genetic disorders are viewed as bad, so temper expectations with any plant you start from a bagseed.
But sometimes you get lucky and find a mature seed in some really nice herb. Strains like the legendary Chemdog wouldn’t be possible without adventurous smokers planting and proliferating the seeds they found in a bag of kind bud.
So don’t discount bud because it has a seed or two in it. While not ideal, it could be the origins of the next great weed strain.
Ask yourself a few questions to decide if it’s worth the time and energy to grow the seed.
Was the seed found in good weed?
If you don’t like the flavor, effects, or even the look of the bud, then it’s probably not worth growing.
Are you ready to grow?
Growing marijuana takes a certain level of commitment: time, energy, and financial resources, so be sure you can commit to the whole process.
Is the seed viable?
For a seed to be viable, it must be mature enough to have a completely formed genetic blueprint, and it must be strong enough to germinate and pop through its hard casing and sprout its crucial taproot.
There are a few indicators that will give you a sense of whether the seed is worth germinating.
- Tiger stripes—dark stripes on the seed which resemble veins on a leaf are generally good
- Solid shell—a seed should be able to withstand a little pressure when pinched between your fingers; if it crumbles or cracks, it’s no good
Immature seeds tend to be light in color and have a soft outer shell.
In some cases, even if a seed isn’t completely mature, there’s still a chance it could be viable. But often these are extremely weak, take long to develop, and express other unfavorable characteristics. Growers usually discard weak plants to free up space.
You might also find a mature seed that has been physically damaged through poor handling, like rough trimming. In those cases, it probably isn’t worth the effort to try and germinate the seed.
But if the seed you found looks decent, you might as well germinate it and see what sprouts.
Time to germinate
Viable or not, there’s only one sure way to find out if a bagseed will grow. If you’re simply curious to learn and not as concerned with the overall outcome, you can plant a couple of bagseeds outside and see what happens.
If you’re ready for a more serious approach, make sure you have the space for a proper garden and pop the seeds to see what fruit they bear.
Even if your seed sprouts fast and grows vigorously, it still has roughly a 50/50 chance of being female and producing buds, instead of turning out to be a male.
Remember, once a seed germinates, the real work begins. Sexing, selecting, vegetative growth, flowering, and the eventual harvest all lie ahead.
How to buy cannabis seeds
Cannabis seeds can be found on numerous online seed banks, but note that it is illegal to bring seeds into the US and Customs will seize any cannabis seeds that they find in packages or on a person. In legal and medical states, you may purchase seeds at a dispensary.
Will Hyde and Trevor Hennings contributed to this article.
Want to grow weed from seeds? Learn how weed seeds work, how to sex marijuana plants, and how to properly germinate your cannabis seeds.
How to Pick Male Plants and Make Cannabis Seeds
Why Every Home Grower Should Make Seeds (At Least Once)
I encourage growers to make seeds for themselves. A lot of people have been asking how, so I put together these basic tips. Hopefully, it helps a lot of people and is fairly straightforward. This isn’t meant to make you a breeder or share all my techniques or secrets, this is to familiarize you with the process of creating seeds.
It’s easy to make your own cannabis seeds at home!
It’s a shame that many grow books tell you only to throw away your males. New growers may not know, but anyone who’s grown for even just a few years gets to the point where they wish they still had something they grew in the past, which is no longer available in seed or clone for whatever reason. The older you get the more it happens. Seed lines disappear entirely once they run out, and due to people not making their own. It’s good to be self-sufficient.
While it’s always fun to check out the hard work of your favorite breeders and their strains, it’s equally as important to pollinate a branch or two for yourself here and there and see what magic you can create or preserve. Please share this article if it helps or inspires you. Big agriculture is coming to the cannabis growing world and has the ability to change the plant forever once contamination happens, just like in the veggie world. We are losing genetic diversity fast as thousands of unique strains are lost. Please do your part if you are passionate!
Make your own seeds to save special or unique genetics
How to Make Your Own Cannabis Seeds at Home
These are basic starting points for the home grower. I believe every person who grows cannabis needs to have this skill. Every strain goes away over time when people don’t make more seeds. Growers should know how to make their own seeds for preservation and sustainability. These skills can go a long way. The precursor to serious breeding is the basic technique of creating the seed.
1.) Grow Male Plants
Male plants can be grown in very basic conditions in an isolated space, then flowered for pollen. Males can be started flowering next to females with a close watch for the first week or two, but be careful and remove them before pollen sacks form, bursting open and pollinating everything.
Branches can be cut off and put into a cup of water on a windowsill or under a CFL bulb, even under veg light cycle once they are in bloom. Pollen can be collected within a week from these branches, saving lots of space. Males can also be cloned or flowered very small based on your needs.
Best, however, is flowering the males in their own tent or space. With a carbon filter and negative pressure, and careful practices, you can avoid spreading pollen to unwanted spaces. The longer you flower a male out past its initial beginning release of pollen, the more of its flowering traits you will see! (More on best male plant selection below)
A beautiful male cannabis plant
2.) Collect Pollen
Pollen can be collected by tapping a budding branch gently over a piece of paper. Pollen will spread easily in the air, so make sure to turn off all fans. Visit males only after tending to female plants so you don’t accidentally bring any stray pollen on your clothes or hair!
A male plant right as pollen sacs start opening
3.) Pollinate Buds
Take out your female to be pollinated or shut off all circulation fans. Gently apply pollen to a labeled branch. The pollen must meet the white flowering hairs to create seeds. Week 3-5 is best to pollinate, and you can do a single bud or branch per plant and keep the rest seedless.
Every pollinated branch should be labeled properly, your memory will not last as you think it will. A proper branch label includes dates, strain names, breeder/sources, and has the female listed first and male listed second. An example label looks like this: 4/20/2015 – Star Pupil (Mass Medical Strains) x Prayer Tower Sativa 9 (Bodhi Seeds) and the label should be kept with the seeds when they are finished. As years go by, you will be thankful for the dates and breeder information, which can escape our memory on occasion.
Overhead shot of a seeded cannabis plant. Strain is “Star Pupil”
4.) Deactivate Stray Pollen
Water generally deactivates pollen, wash clothes and shower if needed after handling. 3+ hours after pollination, the plant can be sprayed down with water to deactivate stray pollen and can be brought back into grow room and fans turned back on.
Avoid spreading pollen unintentionally. It can get everywhere!
A male cannabis plant exploding with pollen. Strain: Prayer Tower Sativa (below)
5.) Collect Seeds
Seeds are done in 2-6 weeks and should be dried in the bud when the plant is harvested. Seeds should be sproutable within one month of drying.
Female buds become swollen with seeds
A cannabis seed peaking out
What strains should I use?
Any strain with traits that you like, which speaks to you, or seems like a good cross, means your intuition is telling you something. Starting with stabilized or homogeneous lines is always a benefit. Certain genes such as Cookies, OG, and Diesels, are full of hermaphrodites and should be used with caution, only to be bred with if they are really your #1 passion. Follow your heart.
Crossing two unrelated strains for the first time is called an F1. Crossing a brother and sister F1 of the same strain creates an F2, and so on. Selections play a huge role in what the outcome will be. Making F2 seeds of an F1 you purchased, will not give you the same seeds. Rather, you will see new phenotypes resembling some of the parents and their parents, etc. With huge potential to find new special plants within.
Many combinations will work great, and some will not. If you fail, try again, selecting new parents. Each combination is unique. A and B might work great together, and C and D might work well together, there’s still a possibility that A and C combine to create junk. Every parental combo is unique!
If you see a unique trait that you like, make seeds!
Selecting a good female is easy, flower female plants from seed and again from clone to test stability. Smoke test is important. A potential mother plant should have all the high-quality traits that matter to you. Hermaphroditic plants are to be avoided.
Female plants to be pollinated should have all your ideal traits. Use only your best females.
Selecting a male, you have to use your senses a lot. The ones who grow best and smell best are a good starting point. Structure and root growth are important. Hollow stems may indicate high THC potential. Cut the top off a couple nodes down and find out. First showing or fastest flowering males are generally discarded. Very slow blooming late males are often times more recessive although not always. I like them. Males will start to drop pollen before they are “done” flowering enough to see their true traits. As a beginner, you can use the pollen at any stage, but those doing real selections are advised to always flower your males for weeks after the pollen starts.
For male selections, a strain you’ve grown before and enjoyed the females is a safe starting point.
Watch for resin production, look at how the flower clusters stack and produce. The male flowers form similarly to female flowers, large yield potential is often apparent in largely formed male clusters that can look almost like female buds from a distance. The more males you have to choose from, the more fun you will have!
Male plants can be a lot of fun to grow, too. Just like the females of the genetics they come from, they all have their own characteristics and unique traits. Once you get into “hunting males” you could get hooked! Some of my prized male selections from over the years are shown here. You’ll see resin production and traits of large floral clusters, as well as unique coloration!
This male Weapon X cannabis plant is about to pop!
Male Blue Magoo BX looking trippy under LEDs
Strain: Mr. E Reversed
For more advanced breeding selections, I recommend starting ideally a few hundred seeds. (For beginners, as many as you can is great, will help you find the best ones you can. Use your intuition!) Plants can be weeded out every few weeks selecting only the best contenders to flower out, and a lot can be achieved in a spare tent or closet this way, while still selecting through large populations! Clones of a prized breeding male may be kept in veg the same way females are, to be used again and again once their offspring are proven good! This is how a breeder can create the same batch of seeds for years and years, by using the exact same parents held in clone form.
These tips are just the beginning, and the purpose isn’t to teach you how to breed, but to teach you how to learn your own path and style of creating seeds and preserving our very special plant. The seeds you create will always be a very special grow for YOU.
Making your own seeds is more important than ever. We must do our part to preserve the natural genetic diversity of this healing plant as it has evolved for millions of years. Home growing is an important skill as commercial and medical cannabis is increasingly full of toxins and scary new technology. Please grow responsibly with love.
About the Author
Star Pupil strives to copy nature while incorporating breeding techniques and plant knowledge passed down from generations of experienced growers. Mass Medical Strains is located in western Massachusetts and all breeding and growing methods are 100% organic. Each and every plant is grown and harvested with wholesome intentions and positive vibes.
- Mass Medical Strains Website
- Instagram account (Note from Nebula Haze: Check out their Instagram to see new pictures of all their strains!)
How to Pick Male Plants and Make Cannabis Seeds Why Every Home Grower Should Make Seeds (At Least Once) I encourage growers to make seeds for themselves. A lot of people have been asking how,