by Jorge Cervantes
Harvest when plants are at peak ripeness. Harvest timing is critical. The peak harvest window is open for roughly 5–7 days. Most growers manicure harvested buds before drying them slowly and evenly so THC is preserved. After drying, buds must cure so that full aroma and flavor develop. Like a fine wine, aging (curing) improves taste and fragrance. Once cured, proper storage will ensure buds retain all of their essential qualities.
Pungent marijuana odors are often a problem around harvest time. To minimize odors keep the drying and trimming room well ventilated so fragrances do not linger. Keep rooms cool, below 70°F (21°C) so essential cannabis oils release few pungent aromas. An air conditioner works well to keep odors to a minimum in sealed rooms. A carbon filter will remove odors in the drying/ manicuring room and will also treat expelled air.
Irrigate with plain water or clearing solution to remove residual fertilizers in foliage and soil. Give plants plain water the last 7–14 days before harvest. Make sure to let 10–20 percent of the water drain out the bottom of containers. Clearing solutions remove fertilizer residue faster and are used the last few days before harvest.
Change the nutrient solution to plain water in recirculating hydroponic systems 7–10 days before harvest. Continue to top off the reservoir with “fresh” water until harvest, or use a clearing solution as per directions.
Do not water for 1–2 days before harvest, so plants are pre-dried at harvest. Let the soil dry out but do not let the plants wilt.
Give plants total darkness for 48 hours just before harvest so that more resin develops on buds.
How to tell when fertilizer will affect taste
• Leaf tips and fringes are burned
• Leaves are brittle at harvest
• Buds crackle when burning
• Buds smell like chemicals
• Buds taste like fertilizer
At harvest all plant growth and THC production stop. THC content cannot increase after harvest. In fact, it can only decline. Slow THC decomposition by keeping harvested buds out of extended exposure to light and warm temperatures (above 80°F [27°C]); jostling and bruising from handling; and damp, humid environments.
Mind-bending psychoactive THC (tetrahydrocannibinol) is located in leaves, flower buds, and stalked glandular trichomes. The majority of THC is found on female (sinsemilla) plants in the resin glands or trichomes on flower tops. Stalked trichomes look like a small post with a ball on top. These trichomes develop most heavily on buds and small leaves. THC is most concentrated where the stalk meets the ball of the resin gland.
Large female leaves like the Yumboldt at right and male plants contain fewer resin glands and much less mind-altering THC. The THC content found in stems and roots is virtually nonexistent. Male plants, stems, and large leaves hold low levels of THC and are most efficiently used to make hash, concentrated resin.
Remove large leaves while plants are still in the ground. Cut or pluck off the entire leaf and leaf stem. Once the large leaves are fully formed, THC potency has generally peaked. Smaller leaves around buds continue to develop resin until buds are ripe. Peak potency is retained as long as leaves are healthy and green. Harvest yellow and diseased leaves and dispose of them.
Toss leaves into a paper bag, not a plastic bag. Paper bags breathe well and can be closed by folding over the top.
Keep the paper bag in a closet or area with 45–55 percent humidity and 65°–75°F (18°– 24°C) temperature. Reach into the bag once or twice a day and turn leaves so the moist leaves mix with drier leaves. Leaves will be dry to the touch in 5–7 days. Once dry, place leaves in the freezer so they are ready to make hash.
Harvest male plants before they disperse pollen. Most growers remove them from the garden as soon as they are spotted at pre-flowering, near the end of vegetative growth. Male flowers produce visible pollen sacks with viable pollen 2–4 weeks after lights are set to a 12-hour day/night photoperiod.
Put a plastic bag over any male plants that might disperse pollen before cutting the main trunk off at the base. Shake the plant as little as possible to minimize any pollen dissemination. See Marijuana Horticulture: The Indoor/Outdoor Medical Grower’s Bible for complete information on breeding.
Harvest sinsemilla plants 6–12 weeks after inducing flowering with the 12/12 day/night photoperiod. Harvest at the point when THC production is at its peak, before it starts to degrade. Most plants that receive the same amount of light throughout are ready to harvest at the same time. Lower buds that receive less light often take a few more days to mature.
In general, indica and indica-dominant strains are ripe 6–8 weeks after initiating flowering. Sativa and sativa-dominant strains are ready to harvest in 8–12 weeks. Too often growers harvest too early because they are excited to have a crop.
Test for ripeness by removing a small piece of a mature bud. Put it in a microwave oven or conventional oven. Set the microwave on a low power setting and turn on in 10- second bursts until it is dry enough to burn. Place a little bit of the dry bud in a single-hit pipe and sample. The dry, raspy taste will be from fast drying, but you will be able to tell how potent the pot is.
This bud is weeks from harvest. Wait at least 6 weeks before testing buds for harvest. Many growers harvest lightweight buds before THC develops to full potential.
This bud is still a couple weeks from harvest. The healthy, white fuzzy pistils are still growing and the resin is really starting to accumulate. After a couple of weeks, this bud will be packed with resin. Buds harvested now will yield up to 30 percent less weight.
If harvested a little early pure sativa and sativa-dominant plants contain lower concentrations of all cannabinoids; the stone is often more heady and soaring. Pure indica and indica-dominant strains tend to yield a somewhat less intense body stone.
Resin gland formation slows. Trichomes are starting to degrade faster than they develop. THC production has peaked out. Now is the best time to harvest. Harvest when THC levels are at their peak for maximum mindbending effects. This close up of trichomes shows you what to look for at the time of peak maturity.
Trichomes start to degrade faster and faster. Harvest now for a heavier high.
White pistils turn brownish-red as buds continue to ripen. In some strains, peak potency is when half of the pistils are white and the other half have turned brown. This test is only a general guide to peak potency.
Harvest after peak maturity for higher levels of CBD in relation to THC to yield more of a body stone. Indica, afghani, indica-dominant and afghani-dominant strains harvested now produce a heavier body couch-lock stone. Sativa and sativa-dominant strains harvested after peak potency yield more of a body stone too.