Once your cannabis plants have reached maturity in the late flowering stages, they’ll look and smell beautiful. This is often when cultivators start to think about harvesting. Resist the temptation to harvest early and let your plants mature to get the best quality out of your grow.
While it can be difficult to know when to harvest and a bit of an art at times, the most common way is to look at the trichomes on the plant. They can help you to find the ideal “ripeness” for harvest. Under ripe is never ideal, but some growers like a harvest with over ripe trichomes for a more sedative effect.
What are trichomes, and why do they matter?
Trichomes are the terpene and cannabinoid-rich magic in cannabis. They contain the resin and cannabinoids that give cannabis its psychological and medicinal properties. They’re not unique to cannabis – you’ll find them on other plants, lichens, and algae.
The trichomes are also the part of the plant used to create concentrates. They resemble tiny hairs and can be seen without magnification on well-grown mature cannabis. Magnification at 40x or more will reveal a forest of trichomes that coats the flower. Biologically these trichomes are made to protect the plant from pests, predators, and weather. They help the plants stay healthy and strong through flowering and just so happen to smell delicious to humans.
The three types of trichomes
Capitate-stalked Trichomes are hair-like structures with caps full of cannabinoids and terpenes. They are the most abundant trichomes and the most prevalent during the late stages of flowering. While all trichomes contain the chemicals that contribute to the effect of cannabis, stalked trichomes are the main source of chemicals like cannabinoids and terpenes. Capitate-stalked trichomes are easily visible on cannabis flowers, even more so with a magnification of 40x and greater. Use these as an indicator of trichome ripeness.
Capitate-sessile trichomes are found on the sugar leaf and inner buds. They are not visible without magnification and tend to coat the stalks of the plants. Capitate-sessile trichomes grow very close to the plant’s surface and contain both cannabinoids and terpenes. You will not typically use these trichomes to determine ripe buds vs. unripe buds.
Bulbous Trichomes are smaller still than sessile ones and are found on the stems and leaves more than the flower. These are not often used to identify over ripe trichomes as they are the smallest of the three here. However, they will undergo color changes that are noticeable with magnification.
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The three stages of trichome ripeness
Clear coloring indicates immature trichomes and a plant that is not ready to harvest. They appear clear because they are still empty. They fill themselves with those juicy chemicals we love as they mature. Harvesting at this point would lead to lower-quality cannabis with less effect, flavor, and aroma.
Milky trichomes begin to look cloudy and white. These are now full of cannabinoids and terpenes. Once trichomes have turned this milky color, the time to harvest is just around the corner, typically within ten days.
Amber trichomes are the finishing line for growers. As the plant’s flowering stage reaches its conclusion, the cells creating resin in the trichomes begin to die and give the trichomes an amber-red/brown shade. The amount of amber trichomes on a cannabis plant is how many growers discuss and decide when to harvest. When trichomes begin to turn amber, the plant is very close to its peak maturity. Soon after, it will degrade and lose potency.
How to check trichome ripeness with a hand-held loupe in three steps
Carefully take a look at the trichomes on the plant in its last 2-3 weeks of flower. This can be done with a 40x or greater jeweler’s loupe. Do this regularly to determine your trichomes’ ripeness.
Assess the majority color of the trichomes – are they clear – immature, milky – maturing, or amber – mature? If the answer is clear, you’ve got several weeks to go. If they are starting to turn milky, you have about two weeks. If you see any amber, proceed to step three.
If amber trichomes start appearing, then assess the percentage. When looking at the flower in general, look at the percentage of trichomes that have gone amber. The general number to shoot for is ~15% amber trichomes. This can be more of an art than science, but shooting for about ~15% amber will reduce the chances of over ripe trichomes.
This percentage of amber trichomes will get the plant right at its most ripe and potent stages. There’s some art in this decision and some grower’s preference. Sativas can be pulled a little earlier (like ~10% amber) to maintain the sativa effects, while some indicas can be pulled later to create an added sedative effect.
Other methods of determining harvest ripeness
It’s worth pointing out that other indicators combined with the trichome coloring technique can help you tell when harvest timing is right. One example is checking the pistils (reproductive organs of the female plant) and stigmas for color. The stigmas are also hair-like in structure but are easily visible in and around the cannabis flower. The stigmas grow from the flower’s bract and are biologically meant to catch pollen.
The stigmas that grow from them start white but gradually degrade to orange or red depending on the cultivar. Curious how to recognize immature or (over) ripe trichomes in combination with looking at the pistils and stigmas? Read this article on when to harvest marijuana for more information.
Personally, I pull plants to harvest when they are a little over 10% amber. I believe harvesting based on the percentage of amber trichomes allows you to get the most potent and lovely-smelling cannabis, with ~15% amber being the ideal time. However, you should start looking at the trichomes regularly once harvest is near to determine the best time to pull your plants using a small jeweler’s loupe or other magnification. Your environment, preferences, and cultivar selection impact this decision as well. Remember that deciding when to harvest isn’t the only key to quality. It’s very important to start with high-quality seeds to get hearty plants and great yields. You can find the best seeds at ILGM.com.
Frequently asked questions about trichome ripeness
How long does it take trichomes to turn amber?
When trichomes start changing from clear to milky in late flower, they’ll be amber in 10-14 days, depending on the plant and environment.
What should trichomes look like before flushing?
Start your flush when milky trichomes first appear to allow for 10-14 days of flush before things start going amber.
Can you see trichomes without a magnifying glass?
You can see trichomes without magnification with good eyesight and the right light. You may not be able to see enough detail to get an accurate perspective on trichome ripeness however.
How do you check trichomes with a phone?
If you don’t have a loupe or other means of magnification, you can use your phone to zoom in and capture an image of the trichomes on the plant. Make sure to keep your hand steady or use a tripod, as the zoom function is excellent but can require some extra time to focus.