Many statutes governing the medical use of cannabis include limits on the amount of dried herb or live plants that medical marijuana patients and their authorized caregivers may lawfully possess. Since some statutes employ language referring to, for example, "the amount of marijuana necessary to meet the patient's medical requirements," it becomes important for patients, their attorneys, law enforcement officials and courts to be able determine how much useable medical marijuana plants typically yield; whether those yields differ depending on whether the plant is cultivated indoors or outdoors; and the average doses needed by patients suffering from a range of symptoms.

Outdoor Yields

DEA Plant Yield Study (1992)
"This federally sponsored study is critical because it is the only scientifically derived analysis available on how to estimate cannabis yields. It establishes the principle of square footage of canopy being the key to calculating yield potential. It reports that NIDA research gardens yielded slightly less than 1/2 ounce of sinsemilla bud per square foot and. By including unverified DEA agent field estimates, NIDA devised a formula resulting in 3/4 of an ounce per square foot. This range is consistent with the typical yields I have found in outdoor gardens I have researched, as well as with the evidence I have analyzed in scores of legal cases.Using the yield range expressed in the DEA's 1992 Cannabis Yields report and its supporting data, it is possible to accurately gauge outdoor harvests and also to extrapolate indoor yields."
-- Chris Conrad
Court-qualified cannabis expert

Potency

See Chapter 19, The Potency of Marijuana in Marijuana Myths Marijuana Facts: A Review Of The Scientific Evidence by Lynn Zimmer, Ph.D. and John P. Morgan, M.D.