The harvest window is one aspect of the craft which unfortunately, gets over looked or the grower simply doesn’t have the patience to wait-out the last few days, to insure max THC content. Some strains are better harvested before their peak THC production and some are better harvested after their peak THC production. This is what Robert Clark wrote in his book “Marijuana Botany” about trichomes and what they tell us; “The elevated resin heads appear clear, since fresh resin is still being secreted, often being produced in the cellular head of the trichome. At this time THC acid production is at a peak and CBD acid levels remain stable as the molecules are rapidly converted to THC acids, THC acid synthesis has not been active long enough for a high level of CBN acid to build up from the degradation of THC acid by light and heat. Terpene production is also nearing a peak and the floral clusters are beautifully aromatic. Many cultivators prefer to pick some of their strains during this stage in order to produce marijuana with a clear, cerebral, psychoactive effect It is believed that, in peak floral clusters, the low levels of CBD and CBN allow the high level of THC to act without their sedative effects.”
What the hell does this mean?
When growing Indica hybrids, unless you want to end up on the couch, it’s best to harvest when the trichome heads are fully formed but before they start to cloud over and turn amber. According to the maturation time of the specific strain this could take as little as five days or as long as two weeks. If you allow an Indica to go too long you can dramatically affect the taste and high. Fortunately going too long is not a real problem for most people. I like to study close-up photos taken with a high resolution digital camera; however an inexpensive hand-held microscope works wonders. It almost looks like you are in an alien world when looking at resinated buds using fifty-times-power.
With the Sativa dominant hybrids you want to make sure that all the trichome heads are fully formed and also about thirty percent amber. Letting a plant mature beyond this will risk flavor as well as, the finished smoke may be harsh with very little “high”. There are exceptions as I mentioned; Haze has three different harvest windows all being very late into flower. It is every grower’s job to learn what he or his patients prefer in the terms of “High”.
We have not yet addressed yields because if you are at the third stage of floral maturity with fully form trichomes, then we will have to assume most strains have packed on all their final weight. Even then, there are variables but we can use the guide-lines spelled out below to help gauge the best harvest window for your plants based on the trichomes.
1.[font="] [/font]Fully formed but still clear will provide a cleaner ‘up’ high with less sedative effect; this is the best window for heavy Indicas.
2.[font="] [/font]Fully formed and turning slightly cloudy or milky; this is probably the best time to pick most hybrids available today.
3.[font="] [/font]Fully formed completely cloudy or milky with at least thirty percent of the heads turning amber; this is usually best window for the late maturing Sativa’s such as Haze. This is also a good window when using the plant primarily for Hash production.