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How to Grow Hemp for CBD

Growing hemp for CBD is becoming more popular due to the health benefits of CBD, but there are a few things to learn before considering growing a high CBD strain.

Jerry Golick

Updated December 31, 2020

What is Hemp?

For hundreds of years, hemp was considered one of the most important agricultural crops. It was noted specifically for sails, ropes, and canvas, but also for clothing and medicine. In fact, hemp was considered such an important product, that even as late as in the 1940s, the United States was still encouraging farmers to grow it, even though they had outlawed ‘marijuana’ ten years earlier. Generally speaking, up until 30-40 years ago, there was absolutely no difference between weed and hemp. They only differed in how they were used by the consumer. This all changed when the US government legislated a new definition of hemp as being a cannabis plant with an ultra-low level of the THC cannabinoid. Farmers could grow hemp but not cannabis, despite them being the exact same plant, just bred for different purposes.

Another major change has occurred over the last 5-10 years. While the current legislation mandates THC in hemp be kept low, no restrictions are placed on how much of the CBD cannabinoid can be present in the plant. As CBD became increasingly popular in the world, many farmers turned from growing hemp for its fiber, seeds, and husks, to instead growing hemp for CBD. It should be noted that most hemp also has a fairly low concentration of CBD, so you need to grow quite a bit of it to produce a useful yield. Also, most commercial hemp strains are bred to grow very tall, sometimes above 12 feet. These two factors make commercial hemp unsuitable for most home growers.

Hemp for CBD

For home growers thinking about growing hemp for CBD, the solution is to find high-CBD strains. These are normally classified as cannabis rather than hemp.

Regardless of its name, growing hemp for CBD is an increasingly popular idea for many home growers. The high cost of commercial CBD products and a desire to have full control from seed to harvest have created a real grassroot movement of home growers. Also, because the CBD cannabinoid does not carry the same Reefer Madness stigma as THC, many first-time cannabis consumers are finding this a more palatable option. Finally, as the benefits of CBD consumption are becoming more widely accepted, many people are looking at CBD as a supplement to their regular nutrient regime.

Is Growing Hemp Different from Growing High-THC Cannabis?

If your intention is to grow commercial hemp for CBD, you will find the experience quite different than other cannabis strains. This is because hemp strains tend to be very tall (often between 10-16 feet), and contain only a very small amount of the CBD cannabinoid. This means you will need to grow it outdoors and have a large number of plants, which is simply not practical for most home growers.

Luckily, there are a number of high-CBD strains available that can easily be adapted for indoor growing, and that yield a high enough concentration of CBD to provide a reasonable amount of resin.

Considerations for Growing High CBD Strains

A factor to consider when growing hemp for CBD is the plant phenotype. In general, high-CBD strains tend to be more delicate than their high-THC cousins, having lower yields and needing more ongoing maintenance. First-time growers should be prepared for more failures if they are planning to use a high-CBD strain for their first attempt at growing hemp for CBD.

The actual growing process is almost identical for both high-CBD and high-THC strains. What differs is the amount and type of nutrients used and how it is processed after it is harvested.

If you are considering home-growing a CBD strain, you should take into account how much CBD you will want to consume on a daily basis, the average yield a particular strain offers, and how you intend to consume it. A good rule of thumb is 3:1 to achieve the same yield as a THC-dominant plant, which means a single THC plant will probably yield as much as three high-CBD strain variants.

High-CBD Strains

The CNN 2016 documentary Weeds by Dr. Sanjay Gupta introduced the world to high-CBD strains, particularly Charlotte’s Web. First developed by The Stanley Brothers in Colorado, this plant yields about 13% CBD and almost no THC. Originally derived from hemp, it is now possible to purchase feminized seeds for home growing. Home growers should be aware that this strain is considered sativa-dominant, which means it will grow tall.

High CBD Strain: Harlequin

Harlequin is another very popular high-CBD strain. With a CBD/THC ratio of about 5:2, many consumers believe that it provides tremendous benefits without the psychoactive effects often associated with THC. While it has a relatively short blooming cycle of 7-9 weeks, because it is sativa-dominant, it wants to grow tall and can easily reach six feet in height.

High CBD Strain: Cannatonic

Cannatonic was created by a Spanish seed bank called Resin Seeds. It contains about 10% CBD and 5% THC. Growing to a medium height of between 30-80”, it should provide a reasonable yield. Growers should note that it requires a longer blooming cycle (12 weeks) than many other indoor strains. The ACDC strain is a derivative of Cannatonic, with most of the THC removed. In all other respects, it is similar to Cannatonic from the perspective of growth.

Breeding High CBD Strains

If you are interested in breeding your own high-CBD strain, you will need both male and female plants, and a deep understanding of how to correctly propagate cannabis and stabilize the phenotype. This is a challenging and lengthy process that should only be considered by experienced growers.

How to Grow Hemp for CBD

Regardless of the strain you select, growing hemp for CBD or using high-CBD strains still requires proper growing techniques.

Seeds or Clones?

Depending on where you live, you can start your grow with either seeds or clones. In both cases, make sure you are purchasing from a well-established, reputable breeder. Starting with clones is always easier (and faster) than growing from seeds, however, it can be more challenging to verify what you are purchasing. Since clones cannot be tested for CBD content until they are fully matured, it can be difficult to know exactly what you have bought. If you choose to purchase seeds, make sure they are in the original packaging from the breeder. Don’t accept assurances from the retailer if the seeds are sold in loose, unmarked packaging.

How to Maximize Your Yield

As with all indoor growing, you will want to maximize your yield. Keep in mind that most high-CBD strains are sativa-dominant, which means fluffy, light buds, as opposed to the thick, heavy buds from indica plants. Distance between nodes tends to be longer for sativa-dominant plants, which means fewer colas. High-CBD strains tend to develop smaller colas in most cases when compared to THC plants. These factors all contribute to a lower yield than your previous experience might suggest. To compensate, consider using a screen of green (ScrOG), low stress training (LST), or a super-cropping technique. Be aware that all of these approaches will lengthen your vegetative cycle.

Growing Conditions for High CBD Strains

High-CBD strains can tend to need less nutrients to grow, and can easily suffer from nutrient burn if given too much. Reduce the amount of nutrients by at least 25% once the plants are well established, and then increase as required.

Finally, since most of these strains are sativa-dominant, they will tend to want somewhat higher levels of temperature and humidity. Try to stay between 80-90°F, and keep humidity around 50-60%. Experienced growers will note that this raises concerns for a variety of problems, so keep a close eye on your plants!

Using High-CBD Hemp

How will you be consuming your high-CBD strain cannabis? Smoking is certainly possible and popular, however, many first-time consumers object to the idea of smoking their medicine, and with good reason.

Vaping is certainly a better alternative. Using a good quality vaporizer, it should be possible to inhale the CBD resin without any additional unwanted chemicals.

That being said, a popular preference for CBD is ingestion via an oil, tincture, or spray. Using easy-to-follow extraction techniques, a home grower can safely create an oil-based product that can be stored for a long time and consumed in measured doses. Keep in mind that the extraction process will strip all the cannabinoids from the plant. So, if your plant contains a mix of THC and CBD, so will your oil. If your plant has no THC, then neither will your oil.

Summary

CBD is emerging as a very popular cannabinoid for both long-time cannabis consumers as well as those just getting started. Growing a high-CBD strain at home is well within the reach of even the novice grower, so long as a few simple guidelines are followed. With time and attention, you will soon have your first harvested crop of CBD buds ready for consumption.

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Jerry Golick

Jerry Golick is a Montreal-based medical cannabis activist and writer. He has been promoting the legal use of cannabis for over 30 years. He is motivated by a core belief in righting the injustices the cannabis prohibition has caused. He has lectured on the topic to diverse groups, as well as assisted physicians in developing educational programs on the subject. His articles have previously appeared on Cannabis Digest, Lift, Cashinbis, and other online websites.