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How to Grow Industrial Hemp – The Ultimate Guide

Though many farmers are aware of the vast potential of industrial hemp as a profitable cash crop, most are still ironing out the kinks in their systems to figure out how to grow industrial hemp optimally.

The cash crop is already being worked into field cycles either as an oil seed, fiber, or hybrid crop, depending on the variety planted. However, understanding how to grow industrial hemp requires knowing the legalities around it and the varieties available, as well as optimal soil conditions, climate, and crop rotations.

So, What is Industrial Hemp?

In the United States, most state statutes define hemp as a variety of cannabis with a tetrahydrocannabinol (THC) concentration of 0.3 percent or less. This means that though hemp is a genetic relative of marijuana, it does not contain enough of the psychoactive substance to produce the effects of the drug.

In many states, the definition of hemp also notes that the THC concentration can be taken from any part of the plant and is done so on a dry weight basis.

Legal Questions Around How to Grow Industrial Hemp

Hemp is known to be one of the oldest cultivated crops in the world, playing a prominent role in colonial era farms in the US. However, it was effectively destroyed by the federal government in 1937 — until recent legislation signaled a change in attitude toward the crop.

The Marijuana Tax Act is credited with putting in place taxes, restrictions, and regulations that crippled cannabis farming in the US. Then, under the Controlled Substance Act in 1970, all cannabis was banned.

However, the sprawling 2014 Farm Bill included a provision that allowed states to initiate research programs on hemp cultivation, signaling a change in attitude at the federal level.

Those that read the writing on the wall with regards to the federal government’s changing attitude about hemp weren’t wrong. Spearheaded by Republican Senate Majority Leader Mitch McConnell, language was put in the 2018 Farm Bill that effectively legalized the cultivation of industrial hemp.

The 2018 bill is more expansive than the farm bill signed into law in 2014. It allows for the transfer of hemp-derived products across state lines for commercial or other purposes and does not put restrictions on the sale, transport, or possession of hemp-derived products, so long as those items are produced in a manner in accordance with the law.

However, there are still numerous restrictions — many of them established at the state level — that farmers need to be aware of when growing hemp.

Types of Industrial Hemp Crops

Most farmers deciding how to grow industrial hemp will choose to cultivate fiber hemp crops, grain hemp crops, or cannabinoid hemp crops.

Fiber plants will grow to 6 to 12 feet tall without branching, while grain production will yield crops that are slightly shorter, 6 to 9 feet tall, that do branch. It should be noted that taller plants don’t necessarily yield more grain, and, in fact, shorter plants are preferred for harvesting reasons.

There are also dual-purpose crops, which provide fiber and grain. Most of the French and Romanian cultivars are suitable for both types of crops, but present issues when it comes to harvesting.

Currently, the most lucrative crops are cannabinoid, which is used to produce cannabidiol (CBD). Though CBD has numerous applications, the FDA has yet to establish regulations for the molecule and its inclusion in commercial products. Out of the three primary hemp crops, it is the most difficult to farm, as you will need to fully understand the effects of growing variables and stress in order to produce the most CBD, while keeping the THC at or below .3 percent.

Choosing the Proper Seeds for Hemp Crops

Choosing the best seeds for your hemp farm is essential. Purchasing seeds from a facility with tight quality control standards ensures that the seeds you buy will have desirable characteristics, such as powerful CBD-to-THC ratios, strong plant structure, abundant flowering potential, and vigorous growth.

Ideal Hemp Growing Soil Conditions

With hemp often being touted as a “super crop,” many people overstate its lack of needs when it comes to soil conditions. When you’re looking at how to grow industrial hemp, you need to know your soil — just like any other crop.

Hemp will grow best in loose, well-aerated loam that is extremely fertile. The pH of the soil needs to be above 6.0, with neutral to slightly alkaline soil being optimal.

Soil with high clay content, which is easily compacted, can significantly cut the yield volumes of grain or fiber crops. However, well-drained or tiled clay soil can be suitable for planting. On the other end of the spectrum, sandy soils with good irrigation that can support hemp crops often need additional fertilization, which can make production unprofitable.

In general, your hemp crop will need additional fertilizer, despite myths stating otherwise.

To optimize your crops, you’ll need to add nitrogen or potash inputs. As a rule of thumb — though it varies depending on the quality of your soil and your crop rotations — you’ll need to put about 100-130 pounds of nitrogen in per acre, 45-70 pounds of phosphorus in per acre, and 35-80 of potash in per acre. This will allow you to keep to keep your potassium levels in the medium to high range of more than 250ppm.

If you’re farming seed or fiber, your nitrogen fertilization is especially important. However, you’ll also want to keep other soil nutrients within certain limitations. You will not want the calcium levels to exceed 6,000 ppm, while your phosphorus levels to need to be above 40 ppm and sulfur above 5,000 ppm.

Basically, you’re looking at needing about the same levels of fertilizer inputs that you’d have to use for high-yielding wheat or corn.

Climate for Growing Industrial Hemp

Part of the reason that your soil needs to have quality drainage is that industrial hemp requires the equivalent of 10-13 inches of rainfall during the growing season. In circumstances where that level of moisture is unattainable, it’s important to establish early ground cover to reduce surface evaporation. Once the plants are well-established — after flowering and seed setting — they are much better at surviving drought conditions.

Industrial Farming Raised Bed Crops

Many of the same sort of tools a farmer needs for working raised bed crops at the industrial level, such as tomatoes, can be used for farming hemp. These include raised bed shapers, plastic mulch layers, and transplanters.

Your bed shaper is used to create uniform raised beds for planting your hemp. Depending on the shaper, it’s possible to create beds about 3 feet high and about 30 inches wide, which is ideal for following up with a plastic mulch layer.

The plastic mulch layer, much like the raised bed sharper, does exactly what it sounds like it does: it puts down strips of plastic mulch on your beds, securing them with soil.

Among the transplanters now being marketed to the hemp industry, the C&M transplanter is the most popular. However, any good transplanter will be designed to set plants up straight, have no slippage, have consistent plant-to-plant spacing, and lead to better yields.

In fact, most commercially available farm equipment will also work for hemp cultivation. Nonetheless, you will need to be prepared to do some custom modifications to prevent bushy plants from clogging your machine.

Unfortunately, the machinery you’ll need to process hemp stalks for fiber are more difficult to get ahold of unless you’re in a larger hemp-producing state. If you’re worried about the costs of purchasing such equipment, don’t forget that it’s possible to contract companies to process the raw plant material.

Additionally, it’s important to be familiar with plasticulture farming with drip irrigation. This form of irrigation is especially important if you’re looking at developing your hemp farm in a drought-prone region. The system can reduce your water consumption by as much as 60 percent and increase crop yields by 90 percent when compared to conventional irrigation methods. It’s also possible to manage your nitrogen levels in your soil with a drip irrigation system.

Planning Your Planting Dates

In general, you’ll want to plant your crops once soil temperatures reach about 46 and 50 degrees, though seedlings will germinate and survive just above freezing. This means that you’ll want to look at planting your hemp once the danger of a hard freeze has passed. A good rule of thumb will be putting your crops in slightly before most farmers begin planting their corn.

You’ll also want to keep your eyes on rainfall levels, as getting enough moisture in those first six weeks is essential.

Industrial Hemp Planting Density

To maximize your yield, it’s essential to have the proper planting densities for your industrial hemp, which varies based on the type of crop your planting.

What you are growing for will dictate planting density and strategy. High CBD (8%+) – Low THC (below 0.3%) seeds and clones are sought after and in relatively low supply. The price range on seed like this varies between $1,500/lb and $30,000/lb. Growing for High CBD with seeds has a lot of farmers planting between 3,000 and 10,000 seeds per acre. Trending on the lower end for feminized seed and on the higher end for normal seed. Placing seeds in 30” rows on 30” centers is a common seeding strategy. High CBD clones are commonly planted to prevent male plants and because CBD:THC data may be available prior to planting. Clones are commonly planted in the range of 800-3,000 per acre.

If you’re going for straight biomass, you’ll be able to skip doing the work of raised beds and broadcast seed throughout your entire field with the right estimated density. Seed for fiber and grain does not exhibit high CBD characteristics and is inexpensive comparatively allowing for a very different planting strategy.

However, if you are going to be growing hemp to harvest the flower for CBD, it’s essential to do so in raised bed fields. This method will yield higher quality crops with more potent flowers.

Rotating Your Industrial Hemp Crops

Though you can successfully grow hemp in continuous rotations for several years on the same plots, doing so increases the risk of pest buildup. To avoid increasing the risk of borers, rootworms, and rot in your crops, consider mixing wheat or alfalfa into your rotation.

Also, to avoid the risk of white mold and other issues with your crops, do not use soybeans, edible beans, canola, or sunflowers in your crop rotations.

A four-year rotation is recommended.

Weed and Pest Management for Hemp Crops

When planted in optimal conditions, hemp will quickly germinate and will be 12 inches tall in about three to four weeks, which provides enough shade to significantly suppress nearly all weed growth, including twitch grass.

At this point, there are no insecticides, herbicides, or fungicides registered for use with hemp in the US. This means that — for now — proper crop rotation is your best bet to keep your crops robust.

Do You Want to Go Organic?

Hemp, a fairly resilient crop, can be certified as organic.

Many proponents of hemp production overstate the “minimal” needs of the crop. However, given the lack of insecticides, herbicides, and fungicides registered to be used for hemp, it is very tempting to go the extra miles to get your product certified organic.

Additionally, organic hemp grain is selling for more than twice that of non-organic grain, which is certainly enough to justify the increased costs associated with making your hemp farm organic.

However, the final decision will come down to your long-term plan for your hemp farm and your understanding of long-term market trends.

Final Thoughts: How to Grow Industrial Hemp

In order to succeed as a hemp farmer, you will need to fully understand the agronomic traits of your location and choose the right variety of hemp, based on the marketplace and the qualities of your farm. However, just knowing the basics regarding how to grow industrial hemp will help guide you in making the right choices to tap into this potentially lucrative cash crop.

If you’re wanting to further increase your understanding of how best to break into the hemp industry, local cooperative extension services are extremely valuable resources. This is especially true of the one operated through Colorado State University. The program embraced hemp early and developed a seed certification program; it continues to promote research into hemp cultivation.

Have questions about what seeds are best for your industrial hemp crop? Contact the experts at Bonafide Seeds.

Fallon Hanley

View posts by Fallon Hanley
Fallon boasts 15 years of experience in growing and breeding cannabis and hemp, and managing grows.