One of the biggest challenges for beginners learning how to grow weed is deciding when to harvest their crop. Unfortunately, most beginner cannabis growers harvest their plants too early due to excitement, meaning lower yields and less cannabinoid potency.
There are three primary methods to determine when to harvest cannabis:
1. Breeder Guidelines
Most will provide an estimated flowering period for the strain you purchase, which will be anywhere between 6-10 weeks. If the flowering period is eight weeks, then at the eight-week mark into the flowering stage, you should be able to harvest. However, this is just a general guideline as your growing methods, and environment can impact how quickly your cannabis matures, so it can’t be too precise. Many breeders will also provide a flowering range like 6-8 weeks, which isn’t very helpful with pinning down an exact harvest date.
2. Visually Checking Pistils
Some experienced growers can simply look at their cannabis and determine if it is time to harvest. They just visually check the buds and look at the pistils (the small hair-like fibers that grow out of the bud). These hairs start off white but usually turn orangey-brown and start to curl up close to the bud when it’s time to harvest. Our grower’s guide does not recommend this method because it’s tricky for beginners to recognize these signs, and the pistils of some strains turn brown early while others remain white even when it is time to harvest.
3. Trichome Method
The best way to determine whether it is harvest time is by examining the trichomes on the buds. Trichomes (aka trics) are the crystal bits on the buds and sugar leaves. They’re the resin glands that are filled with all the good things you want, like cannabinoids and terpenes. These slender, resin-filled stalks with bulbous heads look sort of like tiny mushrooms and grow all over the buds’ surface. Trichomes are very small, so you can’t see them well enough with the naked eye – you’ll need a magnifying glass or scope in the 20-60x range.
You should start monitoring your trichomes about two weeks before the expected harvest provided by the breeder (around the same time as your start flushing your plants). The resin starts off clear, then as the plant ages, it turns milky and finally amber. Ensure you are checking the trichomes on the actual bud as the ones on the sugar leaves tight to the bud will mature faster and aren’t the best indication of the bud’s ripeness.
When the trichomes are completely clear, the plant is not ready to harvest. When almost all of them turn milky, the plant has the highest THC levels and can be harvested. While opinions vary regarding the exact ratio of each type for harvesting, as a general rule, when the majority of the trics are milky, and 10-20% of them are amber, it is probably time to harvest the plants. People often say that an early, milky trichome harvest produces more of a head high, whereas the more amber trichomes give a more stoned effect or a body high.
When you’re trying to decide when to harvest your cannabis plants, try to remember that this should be a fun process – you’ve finally made it to the finish line. Many growers worry about harvesting at the exact right time to achieve desired effects. But the truth is, your genetics (i.e., the strain you choose) will primarily determine the cannabinoid content and type of high you feel, although you should still wait at least until you see some clear maturity signs like coiled orange pistils and milky trichomes. A couple of days may seem to change the color of your trichomes dramatically, but this should only slightly impact the effects.