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harvesting hemp seeds

Hemp Seeds: A Step-By-Step Guide on Growing Hemp

Growing industrial hemp

Hemp is a dynamic crop that is easy to grow, maintain, and harvest. It also has a multitude of uses from medicinal to manufacturing. Here is a step-by-step guide to help you begin growing hemp seeds.

What You’ll Need

  • Planting Supplies
  • Hemp Seeds
  • Water Source
  • Well Draining Soil (ph6-7.5)
  • Garden Shovel (for moving soil)
  • Garden Hoe (for moving soil)

Harvesting Supplies

  • 1 Tarp
  • 2 5 Gallon Buckets
  • 1 scythe or garden shears/snips
  • 1 Stick, Club, or Bat
  • Refrigerator

Getting Started

First, we want to check the condition of the soil where you will be planting your hemp seeds. A simple soil test is quick and easy. Start by going to your local hardware store and purchasing a soil test kit. There are a number of kits on the market, so choose the one that fits you best. I like using Land Grant Labs. They provide a print out of the results, and recommendations on how to correct or solve a soil issue. Your local agricultural center can also provide means for soil testing.

Sending in a soil sample before sowing your hemp seeds is very important. Kush recommends doing a few soil tests from different labs. This will help you to have a broader idea of what is going in the soil, but one test will do the job to get started.

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Soil Fact: Hemp typically prefers a soil with a ph of 6 to 7.5.

Prepping the soil

Once the results of your soil test are returned, take any recommended actions. Supplement your soil with the recommended minerals to ensure that the plants will have all the nutrients they need for the season. Another way to insure a proper mineral composition is to plant a cover crop the previous season.

Like growing any crop sustainably for the long term you must feed the soil and not the plant. Hemp is no exception to using proper crop rotation methods, such as:

Year 1: Hemp (planted for harvest)
Year 2: Common Buckwheat (planted for soil phosphorus regeneration)
Year 3: Hemp (planted for harvest)
Year 4: Alfalfa (Planted for soil nitrogen regeneration)

Following this cycle of crop rotation will make for better, healthier, dynamic soil. By design, it also leads to a better, healthier, dynamic hemp product for generations to come.

If the soil is healthy and vibrant, anything it grows will also be healthy and vibrant. My favorite cover crop is Common Buckwheat. It’s inexpensive, covers a lot of ground, smothers out common weeds, works well in poor soils, and is better than other cover crops at retrieving phosphorous. Additionally, buckwheat helps later crops with fruiting, flowering, and root growth.

If you don’t the time to plant a cover crop this season then simple supplementation from your local agriculture supply store can be a quick and effective way to ensure you have organic mineral content in time for the current season.

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Sowing Seeds

Planting Hemp seeds from April-June is advised, although conditions are more important than the calendar date. A soil temperature above 50°F, in Full-Sun (6-8 hours of sunlight a day), and well drained soil is ideal. Upon planting, follow with a deep watering to promote germination. You should be able to see seed-sprouts emerge anywhere between 5-10 days although some seeds can take as long as two weeks.

Hemp seeds should be deeply water once a week, early in the morning, or at dusk to prevent evaporation. Watering is most important between the first 6 weeks, after this, hemp becomes mostly drought tolerant.

If you starting seeds inside, it is recommended to do so around May 1st. This allows 3 weeks of growth before transplanting outside. Seedlings should be lightly watered each day and stored in a warm (above 70°F) room with 6-8 hours of direct to indirect sunlight. When the stems near the base begin to become “woody” and more stable, the seeds are ready to make the move outdoors.

In some hemp fields, seed spacing is commonly 4’x6’, due to how big the plant will be at full maturity. This additional space also gives room to harvest material from the plant. Similar to an orange grove or apple orchard, all hemp plants have their own space. This is more convenient for the farmer, due to the creation of rows to walk, room between plants for inspection, and easier movement at harvest time. This is not necessary, but keeps the field orderly and manageable.

However, hemp can be planted very densley with no issues as well. Not only will this help keep weeds at bay, but it will provide more harvest potential. Another benefit is that the hemp crops do not need to be inspected as frequently due to the sheer quantity.

Either method of planting your hemp crops is acceptable.

Growing Hemp: Frequently Asked Questions About Planting Hemp Seeds

What is the ideal soil temperature for planting hemp seeds?

Hemp seeds should be planted in soil as close to 50°F as possible.

What level of sun is needed for hemp seeds?

Hemp should be planted in full sun.

When is the best time of year to plan hemp seeds?

Ideally, you should plan to plant your seeds from April-June.

How many days does it take for hemp seeds to emerge?

On average, it takes about 5-10 days for hemp seeds to begin to emerge from the soil.

What is the proper seed depth for hemp?

Hemp seeds should be planted ¼” to ½” deep into the soil.

What is the proper row spacing for hemp plants?

Hemp should have at least 4” between each seed when planting.

When do hemp plants reach maturity?

On average, hemp reaches maturity between 8-16 weeks (based on species).

When should you sow hemp seeds?

2 to 4 weeks after your average last freeze when soil temp is above 46F, or anytime up to 4 weeks

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How to Harvest Hemp

Hemp can be harvested for fiber or seeds.

As soon as seeds develop (after 4-8 weeks) fiber can be harvested. The longer you wait to harvest the stalk for fiber, the more durable the fiber will be. You can begin harvesting hemp fiber as early as seeds are visible.

To harvest hemp fiber
  1. Cut stalks 2-3 cm from the soil using shears or a scythe
  2. Lay the stalks on the ground to dry, also called “retting.” This process allows moisture and microbes to break down the stalk so that fiber is easier to remove. “Retting” can also be done by submerging the stalks in water for up to 7-10 days. Retting will not occur under 41°F or above 104°F. This process can take up to 5 weeks.
  3. Allow to dry completely before storing
  4. Once dried hemp can be bound in stacks, bales, or bundles for storage
  5. Hold cutting over a tarp or collection bin in a well ventilated area
  6. Thrash the clipping with a stick, club, or bat to kock all the seeds off onto the tarp/bin
  7. After harvesting each plant as a whole you will pour the seeds into a 5 gallon bucket

For seed harvest, wait 12-16 weeks until you see seeds forming at the top of the crop. Some seeds lower on the plant may be harder, where as some closer to the top may be soft and green. This is normal and means your plant is not quite ready for seed harvest. For maximum harvest wait until the majority of the seeds are hard.

How to Get seeds from your hemp crop:
  1. Cleanly cut just below the lowest seed pod off the stalk with shears/snips or scythe.
  2. Hold cutting over a tarp or collection bin in a well ventilated area.
  3. Thrash the clipping with a stick, club, or bat to kock all the seeds off onto the tarp/bin.
  4. After harvesting each plant as a whole you will pour the seeds into a 5 gallon bucket.
  5. Hold a bucket one foot above another bucket and pour the seeds back and forth. When the seeds are poured from one bucket into the next, the wind (or a fan) moving between will blow away all the residue and debris. Repeat this step 5-10 times until all debris and residue has been removed. This process is called “winnowing.”
  6. You can now pour seeds into a refrigerator safe bin with a lid and store between 32-40°F.

Once the seeds are harvested, you can harvest the fiber from the fully matured stalk as well. Fully utilizing the crop to its maximum potential by repeating the steps for “fiber harvesting”, listed above.

Planting Hemp seeds from April-June is advised, although conditions are more important than the calendar date. A soil temperature above 50°F, in full sun.

How and When to Harvest Hemp

Home » How and When to Harvest Hemp

FAQs in this post –

Unsuitable harvesting can render countless acres of viable hemp useless. That’s why it’s so vital to consider your final product and the quality you hope to achieve before choosing the appropriate harvesting method. And with thousands of uses for hemp, the answer is not always so obvious. Moreover, the harvest method you choose must produce a legally compliant crop that tests below .3% THC, and is safe to ingest. In order to be sure of that, you must meticulously time your harvest and test samples of the crop throughout the lifecycle.

At ACS Laboratory, we offer testing solutions for every step of the hemp cultivation process and have compiled a list of frequently asked harvesting questions to help set you up for success. With your product, compliance and product safety in mind, let’s dive into the details of how and when to harvest your hemp.

FAQs

When is hemp harvest season?

Unlike perennial plants that come and go each year, hemp is an annual plant . That means under most circumstances it grows from a seed to a plant in 90-120 days and its buds blossom once before dying off for the next crops to be planted. Hemp is affected by seasonal changes so once the days start to shorten, the crop stops growing tall and begins producing flower buds instead. That’s why the busy season for hemp harvesting in most states is October , also known as Croptober .

However, if you’re growing indoors, technically you can create Croptober all year ‘round by altering temperatures, lighting, moisture and other required conditions. Additionally in warmer climates with proper greenhouse support you may be able to achieve 2 turns a year. This would include 6-8 weeks in the greenhouse and 8-10 weeks in the field for full bloom. The key is to test your product throughout its lifecycle and create an ideal growth environment based on your location and capabilities. Then inspect your plants to ensure that they’ve matured to an optimal stage before you begin harvest.

Can hemp crops be harvested by hand?

Yes. While this process is time consuming and may be costly, sometimes hand harvesting is the optimal choice. If you’re growing hemp for smokable flower or CBD extraction, you may opt to cut the plants by hand to ensure that you carefully collect and maintain the integrity of each bud. Additionally, if you have a small farm or lack access to machinery, you may also want to harvest by hand. In this case you may use tobacco knives or shearers to cut the plants before loading them on to trailers and carefully transporting them to a facility for drying and curing.

But harvesting by hand is also time-consuming and labor-intensive, so if you’re a first-time hemp cultivator, start small with an acre or less. Then, keep track of the time and manpower it takes to harvest your hemp plants so you can plan accordingly. For example, if you do not have enough manpower to harvest your crops before they are over-mature, you may accidentally produce a plant with THC higher than .3%. At that point, you must destroy your entire harvest and risk losing the time and money you invested.

Can hemp be harvested with a combine?

Yes – If you are harvesting hemp for its seeds (grain), you may utilize a combine . For this purpose, combine harvesting is highly efficient due to its ability to cut a swath about 40 feet wide through a field. Combines are optimal when harvesting hemp seeds on a wide scale, but they can easily shatter seeds at moisture levels lower than 15%. Combines can also increase levels of microbial contamination if hail or rain flattens the swath of plants into the ground. So you must assess your field for swathing potential and carefully adjust your settings for optimal combine harvesting. According to the Canandian Hemp Trade Alliance (CHTA), you will need to experiment with ground speed, concave openings, and air speed.

CHTA suggests the following as a starting point:

  • Cylinder Speed – 450 – 600 rpm
  • Concave – 30 – 50 mm
  • Wind – 1070 rpm
  • Sieve – 3mm
  • Chaffer – 10mm

How do I harvest smokable hemp flower?

Hemp flowers are very delicate and easy to bruise, which is why most farmers harvest smokable hemp flowers by hand. Harvesting by hand will ensure your hemp flower heads remain clean and their resin trichomes remain intact. Unharmed and mature resin trichomes are vital for smokable hemp flower because they contain most of the full spectrum of cannabinoids (CBD and THC) and terpenes that produce the plant’s flavor, fragrance and therapeutic effects.

For the most efficient hand harvest, you may want to identify the sections where the flowers are the biggest and densest–and start there. Then you’ll cut roughly a foot and a half to two-foot sections of the plants going mostly for the top flowers. In order to conduct this process efficiently, you will need to ensure that you have the right amount of labor based on the number of acres of land you have. For reference, the director of operations and farmer for Swan Lake farms in Oregon, Landon Butterfield said 15 people were able to hand harvest 5 to 6 acres of flowers per day.

When do I harvest hemp for smokable flower?

If harvesting hemp for smokable flower, you probably want it to contain high levels of CBD. You may also want it to contain a delicate balance of terpenes to provide the aroma and flavor you desire. This will provide a high-quality product that customers expect from smokable hemp. But several factors such as environmental conditions and nutrient levels can prevent the plant from reaching the cannabinoid profile you desire. That’s why it’s important to test early, at the vegetative phase to ensure your final plant meets the requirements.

After the vegetative phase, you’ll want to harvest the plant when it is abundant with mature flower heads. If looking through a microscope, the trichomes –tiny hairs growing on the plant–should be a milky white instead of translucent. This indicates that it contains a high concentration of cannabinoids. After harvest, you must ensure that the plant is properly ventilated, without direct sunlight and in a comfortable climate between 60-70° F to prevent contamination and preserve its genetic profile. At this point you’ll want to test your flower to confirm its potency of CBD, THC and terpenes. You’ll also want to guarantee that your harvest is free of toxins such as mildew, bacteria, and pesticides to name a few. At ACS Laboratory, we offer comprehensive flower potency and safety testing to guarantee the quality and compliance of your smokable hemp flower.

How do I harvest hemp for industrial fiber?

Hemp stalks are known for their incredible yield of fibre which can be used for everything from textiles, clothes, and paper. If you’re growing hemp for fibre from its stalks, you’ll want to plant them in close proximity for maximum yield and select seeds that grow tall. Once they are ready for harvest, the process is much less precise and easier than harvesting hemp for its seeds or flowers.

All that you need is specialized equipment for cutting hemp for fibre. According to CHTA, you can use a discbine, a disc mower, or a straight sickle mower for best results. One major advantage of the discbine in particular is that it can cut at speeds of 9mph, much higher than average machinery. If you are harvesting hemp for textiles however, you may want to use a straight sickle mower which leaves stems in tact and neatly organized directly on the ground. All hemp should be harvested approximately 10 cm above the ground to prevent cutting through hard woody portion and ensure that your cutting has much of the fibrous stems as possible. Once harvested, you’ll want to facilitate drying to reduce the potential for mold.

When do I harvest hemp for industrial fiber?

If you’re growing hemp for its stalks and fibre content, you do not need to consider precise levels of cannabinoids or terpenes when determining when to harvest. However you must still ensure that your plant has grown to its optimal height, contains less than .3% THC and is contaminant-free. That means you must carefully choose your seeds based on its strain genetics and test early in the pre-harvest phase to ensure that the crop is clean and contains the amount of THC you expect.

If you’re growing hemp for fibre, you’ll want to harvest the plant when you’ve achieved the maximum volume and quality of stalks. This point is reached prior to seed set and the dying off of the male plants, which can occur between 90-100 days. Generally, you’ll want to harvest your hemp when its flowers first emerge and then store them in a way that prevents over moisturization, which causes mold. Before processing your hemp you’ll want to double check it is below the THC limit and that it is free of any toxins that may compromise the finished product. At ACS we test industrial hemp plants for THC potency and a broad spectrum of possible contaminants.

How do I harvest hemp planned for CBD extraction?

Just like smokeable flower (link to section above) , hemp for CBD extraction is harvested for its flower heads, which contain the bulk of cannabinoids that are later extracted into CBD oils, waxes and creams. That means you’ll likely want to hand harvest your crop utilizing the amount of labor and tools you need to efficiently conduct this precise process.

When to harvest hemp for maximum cannabinoids?

Similar to the process of harvesting hemp for smokeable flower (link to section above) , you’ll want to harvest hemp for CBD extraction when its buds mature to optimal potency. You’ll also want to be on the lookout for mildews and molds, which could compromise the hemp’s floral biomass. As with smokable flower, you may want to test your hemp-for-CBD-extraction early and often for potency to ensure its reaching the level you seek. You also need to test for THC to ensure your crop stays below the legal limit. In addition to potency testing, you’ll want to test for contaminants such as metals, mold, and bacteria throughout the crop’s entire lifecycle.

How do I harvest hemp for seeds?

Hemp seeds, which gather around the heads of the plant are great sources of oils and grains that can be used in food, cosmetics and supplements. If you’re growing hemp for seed production you’ll want to select strains that are shorter in stature with lower fibre production. Then once you’re ready to harvest you may want to use combines to efficiently cut swaths of the plant and prepare for post harvest production. According to the CHTA, Canadian producers have identified the following techniques for best combine practices:

  • Use draper heads because they leave more room for hemp heads
  • Experiment with ground speed, concave openings, sieves, wind speed. See best starting settings above (link to section above).
  • Monitor grain tank and adjust concave to minimize cracking of grain
  • Combine at 15 to 18% moisture.
  • See full list here

When do I harvest seeds from hemp plants?

If you’re harvesting hemp for seeds, cannabinoid and terpene potency don’t really matter except for the 0.3% THC limit. Because of the potential to lose your entire crop if it tests above the legal limit, it’s important to test pre-harvest, during vegetation and after harvest to ensure that it remains compliant.

For optimal harvest, you’ll want to assess female plants at the stage that provides optimum seed yield with minimal immature seeds. When visually inspecting, make sure that the seed heads (buds) are still mostly green. You may notice a few leaves on the seed head turning a brownish color. The stem fibres will have shed most of their leaves, but will not be completely matured. When the seeds at the base of the stem and leaf stalk at the bottom of the seed head begin to turn gray, you’ll know it’s time to harvest. Once your crop is harvested, you’ll want to submit samples for testing to guarantee that is free of mold, mildew, pesticides, and other harmful contaminants.

Understanding how and when to harvest your hemp, along with the tests you need to ensure the product matches your customers’ (and the government’s) expectations is no simple feat. But the opportunities to create a thriving brand and lucrative product are limitless. Through education, trial and error, and testing, you’ll be ready to harvest your hemp for successful commercial sale. Contact the team at ACS Laboratory to learn more about our accredited hemp testing services.

ACS Laboratory in Tampa, FL – How and When to Harvest Hemp . We're an ISO17025 Certified laboratory dedicated to servicing the cannabis and hemp industries from cultivation through to MMTCs and recreational dispensaries.