The answer we’re all thinking is – Not soon enough! For growers, harvesting at the right time is just as important as how you grow the plant. Harvest too soon and you lose potency and cannabis yields; too late and you can end up making a batch of sleep medicine. The hardest part of growing cannabis for many new growers is waiting for the right time to harvest. There is a strong tendency for new growers to harvest the plant early due to excitement.Unfortunately, this often results in low yields and lower-potency buds.
Harvesting marijuana is a bit like harvesting grapes (or other fruits). The longer you wait, the more potent the grape and the stronger the alcohol. With marijuana, the longer you wait, the more cannabinoids there will be.
That means a stronger product.There are many signs that will alert you of this upcoming event. Such as:
- The pistils turning red
- The stem broadening
- Resin on the buds browning and darkening
- Leaves starting to yellow and die
If your plant has flowered and you notice any of these symptoms, the chances are good that you are ready to harvest!
You only need 3 things to determine the best marijuana harvest time:
- The knowledge of when to harvest – You get that here!
- Eyes for visual inspection – You’ve probably had these for a while!
- A magnifying tool – Makes the glittery, resin-filled trichomes on your buds easier to see; although not 100% necessary, this lets you time your harvest perfectly to get the exact effects you’re looking for!
Here are two basic ways of determining the optimum time to harvest marijuana:
Not Ready for Harvest
The vast majority of pistils (hairs) are still white and sticking out straight. This is definitely too early to harvest, and these plants have many weeks to go!
Not yet Ready
We’re waiting for at least half of the white hairs to darken and curl in. Some of the pistils are starting to turn color, but there are far less than 50% curled/darkened pistils. These buds still have several weeks to go before they’ll reach their highest levels of THC. The good news is your buds will get bigger and more dense in that time!
Ready To Harvest
- Harvest when 60-70% of hairs have darkened for highest levels of THC.
- Harvest when 70-90% of hairs have darkened for a more calming, anti-anxiety effect as some THC turns to the more relaxing CBN
- With some strains, you may see a bunch of new pistils appear right when you think you’re getting close. This is normal, but it happens more than 3 times you’ve eventually got to just make the decision and chop.
With some strains, it is much harder to tell when the time is right. Different strains can look different ways at harvest. For example, some strains can keep most of their pistils white even when they’re ready to be harvested.
With this method, you look at the glandular stalked trichomes on the buds under a magnifying glass. Trichomes are the the mushroom-looking growths on cannabis that are responsible for it being so popular! These trichromes are the ‘crystals’, or ‘frosty stuff’ you see accumulating on your bud/leaves. They’re also what makes weed so sticky. You may also see tiny, clear hair-like trichomes without the mushroom head but these don’t affect potency so you can ignore them. You are interested in the trichomes that have a little ball on top. This is where a lot of the THC and other good stuff in cannabis is located. Since these trichomes are what contribute the most to bud potency, being able to tell when they’ve reached their highest levels of THC will help you be able to choose the exact right time to harvest your marijuana. Cannabis trichomes are difficult to see with the naked eye, so you’ll need a jeweler’s loupe or other way to magnify the image in order to use the “trichome method” for determining harvest time.
If you put the loupe right up to your buds, you’ll get a better view of the trichomes, letting you better determine their color and shape.
It can be hard to tell the difference between clear and cloudy trichomes, especially if you don’t see both types of trichomes at the same time! This is completely normal, and it takes a little experience before this part becomes totally easy.
The trichomes in this picture are still mostly clear, but that may be difficult to know immediately if you haven’t really looked at trichomes before! You can see mostly clear trichome heads. This is an indicator that the plant is not quite ready for harvest. But even without looking the trichomes, the the fact that all the pistils are sticking straight out has already shown that this bud isn’t ready. If there aren’t any pistils curling in, it means you still have several weeks to go!
Here are some general rules about harvesting marijuana based on trichomes and the color of the hairs / pistils. If you follow these rules, you’ll know how to harvest weed perfectly every time!
- If white “hairs” are almost all sticking straight out and trichomes are all still translucent (clear) then your plant is too young and not ready for harvest. Harvesting now will result in low yield and non-potent harvests.
- The beginning of the harvest window opens when your plant has mostly stopped growing new white “hairs” or pistils and at least 40% of the white hairs have darkened and curled in.
- Highest level of THC is when many/most of the trichomes have turned milky white / cloudy (when viewed under a magnifier). Trichomes that are milky have the highest levels of THC are “ready to harvest” and contribute to more euphoric and psychoactive effects. At this point 50-70% of the pistils have darkened.
- Some Sativa & Haze strains have trichomes that never really turn amber. If they’ve turned mostly white and don’t seem to be progressing further, it may be time to harvest!
- The most “couchlock” or sedating effect happens towards the end of the pot harvest window, when the trichomes have become a darker color (usually amber/gold). The best results from amber trichomes come from indica strains. The amber/yellow trichomes contribute to a ‘body high’. Some of the THC has converted into less psychoactive CBN, which has calming and anti-anxiety effects. With some strains, the trichomes will even turn red or purple! I like to harvest around when 20% have turned amber. At this point 70-90% of the pistils have darkened. Harvesting later will increase the sedating effects, but may also start reducing the psychoactive effects.
- When trichomes start looking grey or withered, the harvest window has passed, and buds will make you sleepy without many psychoactive effects. Usually it takes several weeks (4 or more) from the beginning of the harvest window for this to happen. It’s much easier to harvest too early than too late!
Harvest your buds earlier, when only 40% of hairs have darkened and curled in and more than half of the trichomes are part clear/ part milky or mostly cloudy/milky. For the “strongest” marijuana buds with the most psychoactive effects, and the highest levels of THC, harvest when almost all trichomes are cloudy/milky. For more relaxing, anti-anxiety buds, wait until at least some of the milky / cloudy trichomes have darkened to amber. More amber = more relaxing, though the effects may be somewhat less psychoactive. Remember, curing your buds properly for at least 2 weeks to a month will also give them more of an anti-anxiety effect.When growing your own marijuana plants, you can certainly sample buds off your plant at different stages to get an idea for what your preferences are.
If you combine both methods you’ll get the best results! Although looking at your buds isn’t the most precise way to know when to harvest, it does give you a really good idea. Try to take everything together. If your buds just have white pistils sticking out, you know for sure that it’s no where close to ready, so you also know that the trichomes on the buds aren’t all cloudy yet. It’s only when your buds are getting close to looking harvest-ready that trichomes are going to have something to tell you!
[Updated, originally published 17.3. 2017]
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