The following is from The cannabinoid content of Cannabis sativa L. grown in England by Fairbairn and Liebmann in the Journal of Pharmacy and Pharmacology, vol 26 (Dec. 1974), pp. 413-419. This work is cited in at least two growing books I know of.
The leaves referred to by the chart are "healthy leaves from plants at vegetative or flowering stages and which were not closely associated with a floral axis." They are not vegetative tops (growing shoots) or flowering tops (buds), as those are two separate, distinct catagories that the researchers differentiate.
|THC content (% of air dried material) and air-dry weight of leaves collected simultaneously at different positions on the plant.|
|Position on Plant||plant 1 (SP5)||plant 2 (SP5)||plant 3 (UNC 335)|
|dry wt (mg)||35||21||28|
|dry wt (mg)||119||74||70|
|dry wt (mg)||314||133||133|
The article also discusses (and shows) the large variability between plants of the same variety -- Table 2 shows how one plant (UNC 255) can have 3 times the %THC as another of the same variety. It also notes that most plants (not all) will tend to have high ratios when comparing the potency from the top to the bottom. But as plant 2 of the SP5 variety shows, it can be nearly uniform.
Now, given that one can easily get high on 1% THC material (be it buds or leaves), it would seem to make sense to keep/smoke/extract the leaves. Hell, the topmost leaves examined in this study have a greater % THC than a great deal of "ditchweed" out there!
Now, you'd thought that 95% of the THC was in the buds. This may actually be true -- it all depends on the total weight of the buds compared to that of the leaves. If you get 10 oz. of (dried) buds from a plant and 0.5 oz. of dried leaves, then yes, 95% of the THC may be in the buds, but that 5% in the leaves is still very adequate to get you high.
Sure, only the topmost leaves on some plants will be worth your while. The point is you should always test some of the leaves to see how potent they are -- throwing away material with >= 3% THC is ludicrous!
|Normalized Versus non-normalized Cannabinoid Averages of
Illicit Cannabis Samples by Year Seized
|* Through June 30|
|* Through June 30, 1994|
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