After spending a few months growing some killer buds you want to make sure you know when to harvest your weed plants. There are a few ways that growers can determine when to harvest marijuana, including looking at trichomes or looking at the appearance of the pistils on the buds.
Different marijuana strains have different flowering times and different harvest windows. Your goal as a grower is to make sure that you’re not harvesting too early or too late, so that you can best maximize the potential potency in your plant. An often repeated rule of thumb is that whenever it looks like you are ready to harvest, you should wait another week.
Since you need to flush your plants with plain water for 1 the 2 weeks before cutting them down, you need to plan for the harvest so it doesn’t sneak up on you. It’s helpful to keep careful notes on your growth cycle including when you flipped the lights to 12-12 and when the flowers started appearing. This will help you determine the correct harvest window for those strains. For example, if you know that you have an 8 week flowering plant you will want to begin your flush at the start of week 7 so that you can then plan to harvestthat they went of the 8th week. Never skip the flush – it’s a critical step to bring out the potential in your buds.
Keep in mind that different problems or environmental stresses during the growing cycle can impact the amount of time it takes for your plants to flower. Things like excess heat, insects, or disease might delay your flowering times.
The best way to tell when to harvest weed: examining trichomes
Looking closely at trichomes are the most effective way to tell when to harvest marijuana. Trichomes are the small resin glands or crystals that you see glittering on the surface of your plan and sugar leaves.
Under magnification each trichome resembles a small mushroom, with a thin stock and a round ball at the top that contains among other things the psychoactive THC, CBD, and other cannabinoids and terpines. As your plant develops these trichomes they go through different stages of appearance, initially clear then turning milky, ending in an amber red color.
The best time to harvest your marijuana for maximum potency is when most of the trichomes have turned cloudy, and only a few have started to turn Amber. If you harvest too early when the trichome heads are clear, the plant will be less potent. And if you wait too long the trichome heads will turn amber. At that point your THC starts degrading into CBN. Too much amber will produce a sleepy, narcotic effect in the final product. While this may be desirable if you looking for a plant that will put you to sleep at night, most growers want to maximize THC to increase the active high. Go for cloudy for best results.
In order to see trichome heads you will need to get a small jewelers loupe or microscope in the 50x to 100x range. These small microscopes are inexpensive and well worth the investment to ensure that your crop reaches maximum potency. Here’s a few good options, we use the Carson MicroBrite Plus and have found it works great since it goes from 60x to 120x with an LED to really let you see the trichomes in great detail.
Marijuana plants typically produced trichomes throughout much of the late stages of flowering. So when you harvest the majority of the trichomes will be cloudy, but there still may be some clear ones that are more recently formed. This can often be confusing for 1st time growers, because if you wait until all the clear turn cloudy then some of the cloudy will start turning Amber.
The second-best way: Examine the pistils or hairs on the bud
Another way to tell when your weed is ready to harvest is to look at the pistils on the buds. Pistils tales are the tiny white hairs that you firstnotice early in the flower stage growing out of the forming buds.
As the plant approaches its harvest window, these hairs will turn orange and later darker-reddish. Pistils will also start to curl in back towards the plant as it becomes ready to harvest. This is a good visual indicator — when all of the hairs have turned orange and curl back in you’re ready to go.
All strains tend to be different though, so looking at the pistils is never as accurate as observing the trichome heads themselves. But if you do not have access to a small microscope then looking at the hairs is a relatively effective way to tell your weed plants are ready.
Worth repeating: don’t rush your harvest. The harvest window for weed typically lasts a week or so. When in doubt, wait a few days. After investing the past 3 months on your grow it’s worth waiting a few days early.
Note that if you’re growing outside, sometime you’ll have to harvest a little earlier than you’d like due to bad weather or early frost. Wet climates are prone to problems such as powdery mildew, so don’t push your luck.
What to do after you harvest your marijuana plants
After you harvest marijuana plants you can trim the plants and then dry them slowly. Then you should cure the buds for a few weeks to bring out the best taste, smell, and smokability. Finally you’re ready to light up!
You made it this far — enjoy your harvest!