Planting cannabis seeds directly into the soil they will flower out in is theoretically speaking the best method possible. Plants never suffer transplanting shock, it cuts out the time, money, and labor spent on starting seedlings and moving them into the field, and often produces the most vigorous and healthy plants. That said its really tough to pull off and we generally don't recommend large-scale direct sow planting to anyone without experience.
Whether you want to try with a few beans, or a few million, here are some basics.
What Is Direct Sow Planting?
Direct sow planting is when growers put the seeds directly into their fields or pots, without any intention of transplanting them. It is common practice in many crops, but requires precision planting equipment. If you are doing it as homegrower in a pot its not overly complicated, but as a scale grower looking to throw in a few hundred acres, it comes with many more challenges.
We hear of growers hitting upwards of 85% germination rates in some areas of their fields, and down to 20-30% in others. Under good conditions, well trained farmers will shoot for a 60-80% stand rate. For vigilant home growers, numbers can be similar.
The photo below is from Horn Creek Hemp, where they did a trial direct seeding plot in mid-June, and the plants far out grew his transplants. Despite vigilant attention he reported only 65% germination rates.
. Choose the Right Time
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Temperature: Cannabis seeds should be planted after the last frost when the soil has warmed up to at least 60°F (10°C) and ideally around 60–70°F (15–21°C). Do not plant in soil temperatures below 60°F.
- Timing: In most climates, late spring (after frost risk has passed) to early summer is the best time. Direct sow planting can prove more difficult in mid summer heat as soil dries quickly. Heavy rains, hail storms, and wind storms are a major threat.
2. Prepare the Soil
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Till/LoosenSoil: Seedlings require loose, non-compacted soil in order to sprout. Well draining sandy loams show the best results for scale growers. A light, well draining potting soil mix can work for home growers.
Soil conditions are one of the most crucial aspects of If the soil holds too much moisture seeds will likely rot. If soil dries out too quickly, seedlings will die. Most importantly, if the soil crusts easily, seedlings will not be able to punch through. Ripping/tilling/discing is mandatory for scale growers. Home growers can use less intrusive methods.
Consistent field conditions will allow for consistent germination rates. If your soil packs/crusts easily, we do not recommend direct sow planting!
- Fertility: Cannabis is a heavy feeder, so ensure the soil is nutrient-rich. Consider adding compost or organic matter to improve soil fertility - but too much as seedlings can burn upon emergence. We always amend our fields with Nutri-Rich 4-3-2.
3. Planting the Seeds
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Spacing: Our most successful direct sow farmers plant at between 7,000-10,000 seeds per acre. This is around around 24-36 inch (60-90 cm) spacing between plants. Most choose to plant on a grid. For a home grower looking to produce monsters, give them at least 6 feet apart.
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Plant Depth: Plant seeds around 1/4-1/2 inch (6-12mm) deep. If the soil is sandy, you can go on the deeper side - but we never recommend over 1/2 inch. It is essential to use a precision planter for growers at scale. At home you can use a stick with measurements marked pretty easily.
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Watering: The most successful large scale direct sow farmers use over-head irrigation methods, such as center pivots. Water the seeds lightly after planting to help settle them into the soil, but avoid over-watering, which can drown the seeds. For home growers, misting the zone seeds are planted in 1-2 times a day can be effective. Just keep an eye on soil conditions and pay attention to the weather.
Using methods such as flood irrigation are problematic in compacting soil, which leads to poor germination rates. Drip irrigation can be very difficult to use because the lines must drip exactly where the seeds are, and shifting lines will leave seedlings un watered. We hand planted 15 acres worth of seeds one year, turned on our drip, and quickly learned when the lines expanded they were no longer dripping over our seeds. Germination rates were AWFUL.
4. Care During Germination
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Watering: Keep the soil consistently moist but not soggy. Over watering will cause seedlings to rot, drying out will kill off the seedlings immediately. Seeds will germinate slower than indoors, generally around 7-14 days depending on the conditions, but it can take a few weeks for plants to establish themselves fully.
If you receive rainfall, it may not be necessary to water. Check your soil regularly across your fields. Low areas where the water puddles will generally have lower rates of germination.
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Weeding: The most labor intensive part of direct sow planting is weeding in the early days. Any other plants that sprout up around your seedlings can swallow them up, and make it difficult to even see your cannabis plants. Some farmers have opted for using laser weeding tools.
Weeding is an area that cannot be overstressed, but once plants are established they can quickly out compete other invaders and the work level drops over the season.
