Knowing When to Harvest Cannabis: Fan Leaves, Pistils, and Trichomes

By Rich Hamilton
Published: October 25, 2022
Key Takeaways

Knowing when to harvest cannabis buds is probably the most often-asked question from new growers. There are several factors letting you know the time is just right to cut those buds, as Rich Hamilton explains.

Harvesting is the most satisfying part of growing cannabis for many people. After months of hard work and watching your plants transform from tiny seedlings into fully mature specimens, now is the time to reap your rewards. However, it’s essential to remain patient and not become too hasty, otherwise you could end up putting all your hard work to waste.


Numerous signs tell when your plants are ready for harvest and at peak-quality levels. Harvesting too late can degrade cannabinoids and leave you with a much more narcotic and drowsy high. Doing it too early will diminish both yields and potency.

Opinions are divided on when exactly you should harvest your buds. You will find that broad guidelines for each strain differ regarding the optimal timeframe. Some indica strains can be ready after eight weeks of flowering, whilst some sativa and autoflowering strains may take as many as 10 weeks.


We will now look at the signs that will let you know the time to dry and cure your buds is upon you. Knowing the cannabis plant’s anatomy is essential to assess ripeness and accurately determine the optimum time for harvest. You must pay attention to the small details to guarantee that you get it spot on.

cannabis with yellowing leaves

Fan Leaves Begin to Turn Yellow

Fan leaves are the large, broad leaves on your plant. Their primary function is to absorb light. The energy absorbed from sunlight is transferred into stored energy through photosynthesis.


During the vegetative phase, yellow leaves are not a good sign. They often signal the presence of nutritional deficiencies. Late into the bloom phase, however, if your plant is loaded with buds, the fan leaves will start to transition toward a yellow color and die off. This occurs because many nutrients find themselves being redirected towards the swelling of the buds. This is easy to spot and a definitive sign that harvest time is almost upon you.

orange cannabis pistils


Pistils Begin to Turn Amber

This is where getting to know your plant helps you out a lot. Pistils are the wispy hair-like structures you see emerging from your cannabis buds. The pistils house the female cannabis plant’s reproductive organs that are waiting to pollinate a male plant and produce a seed. You will notice these wispy whiskers are white during the early stages of the flowering phase. However, as you move through the flowering cycle, you will see they begin to change color. As your plant readies itself for harvest, they will turn darker red, brown, and orange hues.

Never harvest your buds when most of the pistils are still white. This indicates your plants should be left to mature for a little longer.

To ensure optimal THC levels, you should wait until at least 60-70 percent of your pistils have turned an amber color before you begin harvesting. This should give you the highest levels of THC. If you leave it past this point, your THC levels will start to degrade with exposure to oxygen, heat, and light. When this happens, THC transforms into CBN (the sleepy cannabinoid) which is thought only to be one quarter of the strength of THC.


macro image of cannabis trichomes

Trichomes Begin to Turn Milky White

Trichomes are tiny mushroom-shaped glands that populate the flowers and sugar leaves. They are the crown jewels of your bud, producing valuable resin that holds cannabinoids and terpenes. Trichomes are so tiny that it can be difficult to assess them with the naked eye alone. Therefore, I would recommend using magnifying tools to get a closer look.

A small magnifying glass or a jeweler's loupe is perfect for getting you up close and personal with your plant's trichomes. When under magnification, trichomes will seem clear with a crystal-like appearance during the early stage of flowering. This signifies low potency and under-ripe flowers.

As you move toward the end of the flowering phase, however, you will notice the trichomes will change to have a cloudier, milky white appearance. When these tiny resin factories become 50 percent cloudy, it indicates you still have some time to wait. Your flowers are still not fully formed, and they still have a low odor profile.

It is time to harvest when all the trichomes have turned predominantly cloudy. This is when they are bursting with the most significant levels of THC and will deliver the most potent psychoactive effects. If you leave it much longer after this point, your trichomes will change again to an amber color. Harvesting at this stage may produce a more narcotic and physical high as your THC begins to degrade.

Opinion does vary here regarding trichome color. Many growers use it to manipulate their cannabis strain to produce the desired THC levels and effects. Of course, genetics, nutrition, lighting, environment, and cannabinoid and terpene levels will also influence outcomes.

Some people harvest at the 50/50 cloudy and amber point to balance cerebral and physical effects. It is generally perceived that cloudy trichomes produce more uplifting and stimulating clear-headed cerebral effects. In contrast, amber trichomes result in heavier, more intense effects.

It does come down to personal preference and trial and error, so don’t be afraid to experiment a little. The more grow cycles you go through, the more confident you will become. The more you learn to read your plant, the more you will instinctively know the right time to harvest.


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Written by Rich Hamilton | Writer, Consultant, Author of The Growers Guide

Profile Picture of Rich Hamilton

Rich Hamilton has been in the hydroponics industry for more than 20 years, working originally as a general manager in a hydroponics retail outlet before becoming an account manager at Century Growsystems. He enjoys working on a daily basis with shop owners, manufacturers, distributors, and end users to develop premium products.

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