By Noah Chen
Even though farming hemp became legal in 2018, not all forms of the cannabis plant can be grown everywhere. Cannabis comes in two different forms, hemp and marijuana. While they are very similar, the genetics of the marijuana plant cause it to produce high amounts of THC. You’ll mostly find CBD in hemp. CBD is the cannabinoid with many health applications that won’t leave you feeling high. It may contain a little THC, but no more than 0.3 percent.
Hemp plants testing above this threshold get labeled “hot hemp.” Growing it can lead to a costly setback. Hemp technically becomes illegal marijuana when it’s hot. Though authorities are unlikely to arrest you, they will mandate the crop get destroyed. An understanding of hemp genetics, and proper seed choice, will help keep your crop cool.
Hemp genetics cause hot hemp
In 2019, over 12 percent of fields tested hot. Some sources estimated that 30 percent of all hemp harvested that year got destroyed. Many theories, often driven by anecdotal evidence, explain why crops turn hot. Everything from soil composition to water levels and growing temperatures can cause legal hemp to turn hot.
The truth is a bit simpler than all that. In a study published early in 2020 titled, “Development and validation of genetic markers for sex and cannabinoid chemotype in Cannabis sativa L,” researchers found that only the hemp’s genetics were responsible for hot hemp. While certain seeds may proclaim they’ll grow under the legal 0.3 percent THC limit, the reality is some of those seeds may have accidentally gotten pollinated by a marijuana plant, or another hemp plant with high THC. This means some crops have a higher risk of growing hot.
Another source of hot hemp comes with the push to create high CBD hemp varieties. Because growing hemp for CBD is very lucrative, many farmers want plants that yield the highest CBD levels possible. The unfortunate truth is that, without extensive genetic engineering, it is difficult to raise the levels of CBD above 10 percent without also increasing the levels of THC to an illegal level.
How to prevent hot hemp
It is almost impossible to know if a hemp seed will grow hot or not from testing the seed itself. You can find out if a seed is male or female, hemp or marijuana, but these tests are expensive. Because of the way genetics work in the cannabis plant, a hemp seedling may still contain a hidden, high THC allele. This is part of the genetic code not expressed in the individual plant, but may appear in offspring. Hidden alleles can cause later generations of the plant to grow hot.
For this reason, one way to prevent hot hemp is to work with strains that have a proven track record of staying within legal limits of THC. Using clones is also worthwhile. There’s no risk of the genetics changing when you use clones. You’re not working with different generations of a particular strain. Seeds with lower levels of CBD are less likely to grow hot as well. Higher CBD strains pose more risk, but can still yield a solid crop. In Alabama testing occurs no earlier than 15 days within the anticipated harvest date. If your hemp tests hot, you may have to destroy your crop.
Keep your hemp cool with Arbor Vita8
Exceptional custom genetics is a key ingredient to a successful hemp crop — one that keeps its cool. At Arbor Vita8, our partner scientists have developed premium CBD and CBG flower. Our products have THC levels below 0.3 percent. Not only that, our strains are resistant to the elements and diseases. Our hand-picked strains of feminized seeds produce the highest-quality plants. Contact us today to learn more about our available products as well as our complete seed to sale selection of services.