by Nebula Haze
When it comes to trying to increase the amount of CBD in your cannabis for medical reasons, the number one most important thing is choosing to grow a high-CBD strain. (What's the difference between CBD, THC and other cannabinoids?)
The fact is, you can never make a cannabis plant produce more CBD than the amount limited by its genetics. Many of the popular adult-use cannabis strains available today can only produce miniscule amounts of CBD, often 0.5% or lower.
Older cannabis strains tend to have higher CBD levels, especially those from before the year 2000, but many modern strains were bred over several generations exclusively for high THC levels, and CBD levels dwindled over time. It's interesting that now we are going back to producing high-CBD strains. As cannabis becomes more popular, it has become obvious to me that each person is looking for something different.
Example of "Thai Stick" Buds From 1976 – older strains like this one usually have higher levels of CBD than most modern strains
Benefits of CBD
- Lots of evidence that it provides relief for a variety of symptoms including seizures, anxiety, spasms and nausea. It can also provide some people relief from multiple sclerosis, IBS, PTSD, cancer treatments and many other conditions. We are learning more every day!
- Higher levels of CBD in cannabis will mute the psychoactive effects of THC, so that it has less of an effect on your thinking, while still providing the same benefits
- More of a relaxing and less of a "speedy" or "racing" effect with buds.
There are a few things you can do while growing which help maximize the CBD content with the genetics you have, but first lets discuss strains, since that is hands-down the most important part of producing CBD!
What is Considered a "High CBD" Strain?
Generally, strains with 2% or more of CBD is considered to be "high CBD." However, for a lot of patients, the ratio between CBD and THC is more important than the individual percentages. For example, a 1:1 ratio of CBD to THC would mute the effects of THC but the effects would still be there. But once you start getting to the point where you have 2:1 or 3:1 CBD to THC, the buds may not have any noticeable psychoactive effects at all. So something with 12% CBD and 4% THC would not have a whole lot of psychoactive effect even though there's a significant amount of THC there.
- Auto-flowering strains tend to have higher levels of CBD than photoperiod strains because they are descended from high-CBD wild hemp plants. There are also autos that have been specifically bred to produce high CBD levels.
- Many high-CBD strains are becoming available online as seed, since many breeders are now selecting for plants with higher levels of CBD and lower THC
- Unfortunately the best high-CBD plants to grow are the ones that have already been tested for CBD content, which means starting with clones or getting your buds tested. However, for those who don't have access to medical marijuana clones (most of us), there are now seed options that allow you to produce high-CBD levels at home
> Supreme CBD Kush by Nirvana (1:1 ratio – 9.5% THC and 9.5% CBD) – one of the most consistent breeders in the business – you always get exactly what they tell you!
> CBD Medi Haze by CBD Crew (minimum 1:1 up to 1:2 THC/CBD ratio) – This breeder has been specifically breeding high-CBD strains since 2009, far longer than most others
> CBD Mango Haze by CBD Crew (minimum 1:1 up to 1:2 THC/CBD ratio) – Same great breeder, different high-CBD strain
Purchasing from specialized breeders online gives you access to high-CBD strains no matter where you live in the world
- General good care – keep plant healthy and avoid major problems until harvest because sickly plants produce overall lower levels of cannabinoids.
- Harvest at the right time – if you harvest too early your plant won't have reached the highest levels of CBD yet
Growing Tactics That May Increase CBD Levels
This section is based solely on a 6-year study about industrial hemp, which is closely related to but not the same as cannabis varieties grown for their buds. The researchers followed several different types of hemp plants grown outside, and in their study the following factors were associated with the plants producing higher levels of CBD:
- Warm soil temperature
- Warm air temperature
- Lower levels of precipitation (rain)
It's hard to know if these factors will influence the CBD content of cannabis plants grown indoors, but I do think it's a good idea to keep things warm (at least above 70°F/20°C which is the minimum recommended temperature for optimum growth) and avoid overwatering!