So you want to learn how to grow hemp? At the forefront of the emergent billion-dollar cannabis market in the US, hemp is proving to be a commodity of vast utility and promise. With the passing of the 2018 Farm Bill, it’s now legal to cultivate it on an independent and industrial scale.

Treating Your Soil to Grow Hemp

Hemp is a resilient and versatile plant with seeds that will thrive in a variety of climates. But you’ll need to learn how to grow hemp in an optimal climate. Especially arid or desert climates are not ideal to grow hemp in. To get started, the most important thing is treating your soil.

  • You can prepare your soil by breaking it up to allow air, water, and nutrients to vitalize your foundation, a process otherwise known as “aerating”. carefully perforate the top layer of your soil. This mitigates potential soil compaction, excess organic material or lawn thatching that may be starving your roots or bottle-necking vital nutrients and elements. For larger hemp harvests, crop rotation of plants such as alfalfa and buckwheat can be highly effective in reinvigorating and maintaining the fertility of your soil.
  • Your hemp plants will flourish with moisture-rich soil in a consistently warm-weather climate. Testing your soil is vital to establishing a healthy foundation for your crops. High levels of rock phosphate, elemental sulfur, and potassium sulfate can compromise the vitality of your hemp. It’s recommended that you test your soil in either late autumn or early spring for the most accurate results.
  • Avoid planting your crop of hemp in a soil foundation that is “poorly-drained” or otherwise prone to pooling moisture that can create standing water. This can cause severe structural pitfalls to your crop, mosquitoes, and more unwanted aspects. You can test your soil’s draining condition by pouring water into a small hole, about 1 square foot. Take note of how long it takes for the water to drain. Anything over an hour points to a “poorly drained” soil condition. Remember: it’s far simpler to find a better patch of land than to fix “poorly-drained” or infertile soil.

Planting Hemp Seeds

Hemp seeds

Due to the growing variety of hemp’s uses and utility, farmers tend to develop their own unique approaches to planting their seeds but the consensus points to late Spring as the optimal planting period. Depth, spacing, timing, and soil temperature are critical to this part of the process and furthermore critical to the health of your yield. 

  • After the “final frost” of the year is regarded to be the best time to plant hemp seeds. This usually occurs between May and June, specifically between the tail end of May (the third week) and entering June (the first week). It’s purported that mid-June (the 15th) can also be an acceptable planting date as well.
  • Using a soil thermometer, observe your temperature. Consistency is key. When planting seeds, slightly above 50° Fahrenheit is the minimum soil temperature. Once you’ve observed a several day consistency of around 50°, you’re ready to begin planting your hemp seeds.
  • Hemp seeds can be sown as close together as 4 to 6 inches apart. Depending on the dimensions of your planting space, plant them in 15-inch to 30-inch rows. You’ll want to aim for a planting depth of about ½ to ¾ inches. This depth in conjunction with an appropriate watering regimen is crucial. Be sure to deeply water your seeds immediately the following planting to optimize this germination period.

How to Grow and Maintain Your Hemp Crop

Hemp Plant Growing

So how long does it take to grow hemp? The watering regimen of your seedlings is most vital in this growing period. The water evaporation can occur in sunlight hours. Water your seeds once a week in the early morning or around dusk. You will begin to see these seeds sprout as soon as 5-10 days, possibly even up to two weeks. It’s in this period of about 6 weeks that your plants will demand adequate and careful watering. 


When watering, you’ll want to water your plants up to 12-15 inches, roughly. As stated before: hemp enjoys sunny and warm weather. It’s best to water your hemp only when you notice your soil is nearly depleted. Stick a finger into the soil about half an inch and take note whether or not the soil is dry or damp. If dry, water your hemp and soil until the moisture reaches about an inch or two deep. After 6 weeks, the hemp plant will become what is known as drought resistant.

Weed Control

Using what’s known as a per-emergent herbicide you can address the growth of harmful grassy weeds. Hemp plants can see up to 12 inches of vertical growth in up to 2-4 weeks following planting. This growth can often mitigate the large majority of “ground cover” and suppression needed to account for these unwanted weeds. This can help ensure your crop won’t be compromised. 

Fertilizer Application

You’ll want to introduce a nitrogen-rich fertilizer in your soil. This can promote a variety of positive aspects to the growth and maturity of your crop such as plant height, seed yield, and biomass yield. It’s recommended to spread this fertilizer on a, particularly dry or hot day to prevent any uneven spreading or sticking and to immediately water to ensure the fertilizer is absorbed thoroughly into the soil.

Harvesting Hemp

Now that your hemp plants are about to reach full maturity it’s nearly time to harvest! The two main utilities you’ll be able to derive from the hemp plant are fibers and seeds. Harvesting these require their own independent processes. 

Harvesting Hemp Seeds

  • You’ll want to harvest your seeds after about 12-15 weeks of maturation. Near the top of your crop and below the flower of the plant you’ll notice your seed pods. The hardness or softness of these is a clear indicator of whether or not they are ready for harvest. Wait until the majority of your seed pods are hard before harvesting.
  • With a sickle or garden shears, cut your seed pods from underneath the top of your flower. Fashion a funnel system using a bin or tarp of some kind to collect the seeds from the pod.
  • Hold your clippings above your tarp or bin and thrash the pods with a club or a bat to knock the seeds loose. 
  • Using a process called “minnowing”, hold your collection of thrashed seeds above another receptacle and pour them, repeating the process back and forth. The wind (or using a fan if you have one available) will blow away the excess unwanted debris leaving only your hemp seeds.

Harvesting Hemp fiber

  • Between 4-8 weeks is the right time to consider harvesting your hemp fiber. Using a scythe or sickle, you’ll want to cut your stalks a few centimeters from the ground. Remember: the longer you allow your hemp plants to mature, the more durable the fibers will become. 
  • You’ll need to prepare your hemp fiber with a process known as “retting”. Lay the stalks outside for about 5 weeks so that the moisture leaves and loosens up the fiber you’re preparing to utilize. Be sure to take into account that this process can only be executed successfully in weather conditions between 50°-100° Fahrenheit. Once these fibers are fully retted you should store them (vertically) in a cool, dry place. Use a moisture meter to make sure your hemp stalks are at a moisture level of roughly 15%. 
  • You’re now ready to separate your hemp fibers. You can do this with a machine known as a “decorticator“. The decorticator will split the tough exterior of the hemp from the soft tissue within it creating a usable fiber. This fiber has a plethora of applications from clothing to bio-fuel to construction materials.

We’re living through an unprecedented time in history regarding the utility of the cannabis plant. It’s been over 100 years since the American people were free to produce and cultivate hemp for all of its many benefits, unencumbered by criminal legislation and US government policy. With practice and patience, anybody can learn how to grow hemp and move this growing industry another step forward.