Harvesting in the morning ensures that your plant will be at peak THC content, as cannabis has shown THC fluctuations peaking in morning and dropping during the day. Some growers leave their lights off for several days before harvest to increase potency. This seems to have some scientific validity as light has been shown to degrade THC, hence the morning peaks. As light is the degrading factor and the plant still has the ability to manufacture THC during darkness, leaving the lights off for a day or two before harvest likely utilizes the plants stored potential for THC conversion without any opportunity for it to be degraded into cannabinol (CBN) and other breakdown products.
Your magnifying glass is your friend.
Traditionally marijuana has been harvested when the pistils die and the calyx starts to swell into a false seed pod. These days the best growers are getting much more detailed in their harvesting criteria. They take a close look at the trichomes themselves to judge peak harvest. Evidence that this is the only real way to tell peak maturity is in Sagarmatha's strain Matanuska Tundra, which ripens resin glands while most pistils are still alive and white. This seems an odd twist of evolution but proves that the pistil color and ripe glands do not necessarily have any correlation.
A small 25x or more pocket microscope, which can be picked up inexpensively at any electronic store, works well for taking a closer look at trichome development. What we are examining are the capitate stalked glandular trichomes, which will be a round gland head supported on a stalk. The coloration of these gland heads can vary between strains and maturity. Most strains start with clear or slightly amber heads which gradually become opaque when THC levels have peaked and are beginning to degrade. Regardless of the initial colour of the resin head, with careful observation you should be able to see a change in coloration as maturity levels off.
Some cultivators wait for about half of the heads to go opaque before harvest to ensure maximum THC levels in the bud. Of course nothing tells the truth more than your own head, so try samples at various stages to see what's right for you. While you may be increasing the total THC level in the bud by allowing half of the glands to go opaque, the bud will also have a larger proportion of THC breakdown products such as CBNs, which is why some people prefer to harvest earlier while most of the heads are still clear.
References:
1) Starks, Michael. 1977. Marijuana Chemistry Genetics, Processing and Potency. Ronin Publishing, Inc., Berkeley, CA pp. 17-86.
2) McParland, Clarke, Watson. Hemp Diseases and Pests; management and biological control, CABI Publishing, New York, NY
3) Pate, DW, 1994. Chemical ecology of Cannabis. Journal of the International Hemp Association 2: 29, 32-37.
4) Kutscheid, 1973. Quantitative variation in chemical constituents of marihuana from stands of naturalized Cannabis sativa L. in east central Illinois. Economic Botany 27: 193-203.
5) B?csa, M?th? and Hangyel. Effect of nitrogen on tetrahydrocannabinol (THC) content in hemp leaves at different positions. 1997. Journal of the International Hemp Association 4(2): 78 -79.
6) Helen Philbrick and Richard B Gregg. Companion Plants and How to Use Them. 1996. Devin-Adair Company, Old Greenwich, CT.
7) Oldtimer1, 2001. Personal communication
Vic High, 2001. BC Growers Association. Web site and help desk.
9) Hoffman, Dr Silke. 2001. Ultraviolet radiation in the greenhouse. Floraculture International, May 2001. Ball Publishing, Batavia, Illinois. pp18-27.
? An excellent general reference is
Marijuana Botany, by Robert Connell Clarke. Ronin Publishing, Inc. Berkeley, CA
ive done it ure way b4 and wen i checked the run off at the final flush i still had a not normal EC (0.9) so i choose to give it to them to wash them clean, and they seem to like it
