Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

possible. Make sure to install fine screens for air coming into the flowering room and wet them down regularly to discourage rogue pollen. Isolate males until needed. After a month, the male will start reverting to vegetative growth even though it retains viable sacks of pollen. Males can also be cloned and held in the vegetative stage until needed. Induce flowering about three weeks before viable pollen is needed. Within three to five weeks, the male will be full of viable pollen sacks.
    Prolong male harvest by removing flowers with tweezers or fingernails as they appear. New flowers soon emerge after plucking old ones. Continue to remove pollen sacks until females are two weeks from full bloom. Picking off individual male flowers is a tedious, time consuming process, and it is easy to miss a few.
    Harvesting most of the branches, leaving only one or two pollen-bearing limbs, is practical. A single male flower contains enough pollen to fertilize many female ovules; a single branch full of male flowers is necessary to produce enough pollen for most home breeding needs.

Spray male plants with water to deactivate pollen before harvest.
Sinsemilla Harvest
    Sinsemilla flowers are mature from 6-12 weeks after the photoperiod has been changed to 12 hours. The best time to harvest sinsemilla is when THC production has peaked but not yet started the degradation process. Established indoor varieties are bred so the entire plant reaches peak potency at the same time. Lower flower tops that received less light are not as heavily frosted with resin as upper branches and could be slower to mature. Varieties that ripen all at once tend to go through four to five weeks of rapid bud formation before growth levels off. The harvest is taken one to three weeks after growth slows. Pure indica varieties and many indica/sativa crosses are picked six to ten weeks after inducing flowering, while indica crosses with more dominant sativas, such as ‘Skunk #1’, may not be ready for ten weeks. Commercial growers often pick immature six-week-old buds so they can harvest one more crop every year.
    Pure sativa varieties, especially Thai and Asian strains that were grown from native seed, take longer to bloom after turning the light to 12 hours. They could take four months to finish blooming! These types tend to form buds at an even rate throughout flowering with no marked decline in growth rate. Few indoor growers have the time or patience to grow pure sativa varieties because of their long flowering period, leggy stature, and low yield. Buds at the top of the plant often reach peak potency a few days to a couple of weeks before lower buds. Long-blooming equatorial sativas may require several harvests.

Cover male plants with a plastic bag to help contain pollen before removing from the garden.

Cut a male branch from the plant to store and use later before harvesting.

Store male branches in a glass of water for several days. The pollen sacks will continue to open.

Carefully inspect buds for peak ripeness.

Trichomes fight for limited leaf space on this ripe bud. Notice all the pistils have died back and the trichomes are at peak maturity for harvest.

Female calyx development is shown in early, middle, and late stages.

Long thin trichomes are common on most sativa dominant strains. The underside of this leaf is packed with clear glands, some of which are turning amber.

Trichomes in the center of the photo have turned amber, and many have lost the ball on top. The plant was harvested to curtail further trichome degradation.
    Pistils turn from white to brown or brownish-red as the flower tops ripen. Pistils changing color indicates plants are turning ripe; however, it is not the best indicator of peak ripeness. After more hands-on research, I have learned that it is difficult to tell peak ripeness by the color of pistils in all strains. The best gauge of peak ripeness is the color of the resin glands or trichomes.

Early Harvest: These resin glands are in the early stages of formation. Harvest when the trichomes start to turn milky white to amber for the most potent THC.

Late Harvest: Colored light in this photo accentuates the amber color trichomes turn as the harvest window fades.
    Photos on this page courtesy of Joop Dumay, the “Crystalman.” www.crystalman.nl

Peak Harvest: Resin glands start to turn creamy white after trichomes are fully formed. These trichomes signify harvest time!
    Resin glands change colors as they ripen. At