WCBD dominant (Type III) cannabis plants exhibit CBD to THC ratios up to 28:1 on a crop-wide average. For example, if you grow flower that tests at 14% CBD, you can reasonably expect it to contain a minimum of 0.5% total THC.
Research has shown that the CBDA synthase, our favorite gene for its capacity to make CBD, also makes THC. Yes, you heard us correctly. If your plant makes CBD, it also makes THC. THC levels will be present at a minimum of 1 part per 28 parts CBD on a crop-wide average.
What does this mean for CBD producers? There is no such thing as a high CBD producing hemp strain that can be grown to full maturity and remain below 0.3% total THC, nor is it likely to have a plant tested 2 weeks prior to harvest at peak maturity and expect to remain compliant.
At a 28:1 ratio, a CBD flower must be 8% CBD or lower to get a THC percentage at or below the 0.3% federal threshold. Even at 8% you are bound to have outliers that fall above 0.3%. There are plenty of scammers who can show you a single test result from an anomaly of a plant or batch, but for a crop-wide average, higher ratios have yet to be achieved. Seriously question any seed vendor that promises you plants that produce otherwise.
Type III cannabis plants produce cannabinoids at consistent rates and ratios throughout flower. That means the ratio of CBD to THC is constant from the first hairs to peak maturity.
Worried about compliance?
If your state still tests strictly for Delta 9 THC, or allows compliance testing to be done 28 days before harvest, you are in luck for one more season. CBD pure producing plants can be sampled 28 days before harvest and be compliant. For those with a 15-day window, it is possible to test early, and harvest early, but with a guarantee of low cannabinoid levels and unfinished flowers.
Keep in mind, there are no federal regulations that limit the sale of flower that has passed its pre-harvest compliance tests and contains less than 0.3% Delta 9 THC. This is true even if in final batch testing your flower contains over 0.3% total THC. New USDA regulations only apply to pre-harvest tests. Finished flower sales still fall under the rules of the 2014 farm bill. Even after new rules come into effect, flower that has previously passed compliance tests remains just that - compliant.
Still concerned? Stick to CBG seed varieties which have consistently shown ratios of over 90 parts CBG to THC. Manicured flower batches have tested as high as almost 20% in CBG, while still only containing 0.2% total THC.
The graph below shows total cannabinoid content throughout flower as well as testing protocol in several states in terms of days out from harvest at 8 weeks into flower. This information is representative of plants that will reach maturity in 8 weeks, and expect slower gains (a flatter line) on later finishing strains.
Consider the ratios when looking at the numbers below. If your variety is CBD pure, there will always be a minimum of 1 part out of 28 that is THC, and this can be applied roughly to total cannabinoid content.
Here is a sample taken at week 4 of flower from our Special Sauce varietal. As you can see the CBD to THC ratio is close to the 28:1 ratio.
Here Special Sauce is sampled at week 6 of flower - as you can see, total THC numbers are slightly above federal limits of 0.3% total THC. These gains will remain relatively consistent with all pure CBD producing flowers on the market. Once again the CBD to THC ratio remains relatively constant.
Now we have an example of a dried and manicured Special Sauce flower offered by Tweedle Farms. These numbers are meant strictly to show the CBD to THC ratios and are for reference only. We cannot guarantee farmers are able to achieve these numbers, only similar ratios.
CBG - THE EVER COMPLIANT
Here we have a lab result from our White CBG. These plants were left out in the elements for almost a month past when we should have harvested them to see how high THC levels were affected. In our research, CBD dominant varieties tend to produce higher levels of THC when left in the field too long. Fortunately our CBG cultivars still produced only 0.1% total THC even at week 12 of flower.
And finally, here is an example of a dried and trimmed White CBG flower grown by Fusion CBD. Once again these results are meant for reference only, and we cannot guarantee farmers are able to achieve these numbers. Again we have 90:1 CBG to THC ratio.