3 Steps to Controlling THC, CBD, and CBN levels in your marijuana buds
1.) Pick Your Strain (genetics play a big factor for THC and CBD)
If you’ve grown a few different strains before, you probably already realize that the genes of your plants plants play a big role in the results of your marijuana grow.
When it comes to influencing your levels of THC and CBD, the strain you start with is basically the most important factor.
Genetics largely determine the amounts of THC and CBD produced in your buds.
Remember: Unlike THC and CBD discussed in this step, the most practical way to control CBN levels is using the correct harvest, drying, and curing methods. We’ll discuss these in a moment.
Because genes determine many of the cannabinoids levels, for best results you must find a strain which has the effects you are seeking.
Looking for marijuana strains with high THC levels?
THC levels are commonly bragged about. THC is the most psychoactive component of marijuana buds.
Many of the more famous, “ultra-potent” strains are high-THC (low CBD) strains, as well as most pure Sativas.
Looking for marijuana strains with high CBD levels?
Strains with “Afghan” or “Afghani” lineage tend to have higher levels of CBD, as do most non-psychoactive varieties like Ruderalis (auto-flowering) and hemp.
Afghan strains are potent and easy to grow, generally have high CBD content and produce great yields. Therefore strains with Afghan lineage are usually a great choice for beginning growers looking for a marijuana strain with higher levels of CBD.
Ruderalis (auto-flowering) plants are high-CBD yet stay very tiny, so are only recommended for stealth grows or those looking for small amounts of medicine.
2.) Harvest At the Right Time (plays a factor for THC and CBN)
While you cannot control CBD levels with harvest methods, you can influence the the amount of THC and CBN in your buds by choosing the right time to harvest your plant.
CBD levels seem to remain relatively stable for most of the harvesting period.
Pick the right time to harvest by watching:
- Pistils (“white hairs” that grow from new buds)
- Trichomes (crystals or resin glands, the glittery stuff on your marijuana buds)
This is the simplest harvest method. Watch the pistols/hairs growing on the buds and harvest based on how many have darkened and curled in.
- For a speedier high, harvest when about 40% of white hairs have darkened and curled in
- For highest THC levels and buds that make you soar, wait until buds have fattened and 50-70% of the white hairs have darkened and curled in.
- For higher CBN levels, which cause more of a relaxing effect, wait until new white hairs stop growing, and 80-90% of the hairs have darkened and there are few white hairs.
For the marijuana scientist, watching the trichomes gives you a bit more insight into what’s going on with your plant’s cannabinoinds.
Plus it’s really fun to look at trichomes through a jeweler’s loupe or microscope.
- Early on, when there are still many clear trichomes, buds tends to produce a heady, wired kind of high. THC levels are lower at this point, though they’re ramping up each day.
- For highest THC levels, harvest when nearly all the clear trichomes have turned milky white. This will produce buds with the most mind-altering effects.
- For a more relaxing effect, wait to harvest until many of the milky white trichomes have darkened to amber/gold. These amber trichomes have a bit less THC, but more CBN. The presence of CBN often reduces the anxiety some people feel from high THC levels.
There is a lot of variation between strains and people’s preferences, so it is highly recommended you experiment with your plants to see what works best for you.
Important Tip: Exact harvest time isn’t as critical as we once thought.
Don’t stress too much, often buds have similar levels of cannabinoids even when harvested weeks apart.
How do I experiment with harvest time if I only grow 1 or 2 plants?
It is totally okay to harvest different parts of your plants at different times.
Just make sure there is enough green foliage left to support the plant.
Some growers say that harvesting different parts of the plant at different times is stressful for the plant, and that is true.
It’s also been shown that stress near harvest time actually causes an increase in resin/cannabinoid production, which most growers find beneficial.
While you’re in the harvest window, your plant puts all her effort into making the most awesome buds possible.
As long as you have a healthy plant, I highly recommend harvesting different parts of the plant at different times to (labeling them so you remember which one you harvested when!) and find out what works best for you.
3.) Dry and Cure Buds Properly
Most growers agree that drying buds slowly and then curing buds in an air-tight space improves the taste and smell of buds.
Many growers also agree that curing your marijuana buds for 2-4 weeks or longer actually seems to increase the subjective potency of buds.
Curing buds for a longer period causes some of the THC to turn into CBN, which happens as the THC is exposed to air.
Some people also speculate that having a bit of CBN helps “activate” THC effects.
Whether it’s because of this process or or something else, curing marijuana buds has an effect on potency, in addition to improving the taste and smell.
Curing for too long (over 6 months) does not continue to cause any increase in potency. Buds actually start getting less potent as much of the THC degrades.
You can safely store buds longer when marijuana is kept in a dark, cool, dry airtight environment.
Remember: marijuana buds should always be dry prior to any kind of long-term storage, and you may have dry them again if you store them somewhere that has high humidity.