Beyond trichomes: signs that say it’s time to harvest your cannabis

For any cannabis grower, knowing the best time to harvest their marijuana plants is a vital point. You’re probably anxious to try the fruits of your labour after so many months of waiting… but don’t be too hasty, because in this case patience truly is the greatest virtue! In this guide you’ll learn all about the key indicators that mark when cannabis plants are ready to be cut.

The real success of a cannabis grow greatly depends on the grower’s ability to achieve the best yield at the time of harvest. There are a number of factors that play an important role in determining the final quality of the buds. These include the amount of light, irrigation, growing medium, climatic conditions, and the techniques that have been implemented. But another crucial factor that must also be carefully considered is the most suitable time to harvest the plants, which can actually become a double-edged sword.

If you cut your plants too early, you might miss out on potency; but if you cut them too late, your cannabis could turn into a big disappointment. That’s why knowing how to ‘read’ your plants is essential to determine the best time for harvest. By asking yourself the following questions you’ll definitely be much closer to achieving your goal!

What’s the flowering time of the strain that you’re growing?

This is in fact the less precise measure for knowing when to harvest your cannabis plants. This information should be used to determine a time window in which to act, but it is not indicative of when the plants are at their optimum point of maturation.

Not all varieties take the same time to flower. Indicas usually have shorter flowering times than sativas. These should simply be used as a guideline, considering that a specific plant may be ready either a week earlier or a week later. Therefore, it’s also important to get to know other signals.

What colour are the trichomes?

Keeping an eye on the trichomes (i.e. the small resin glands) is one of the safest ways to know when it’s time to harvest. Their appearance will determine the potency of the cannabinoids that have accumulated inside them. When cannabis plants are cut too soon, their resin glands contain less of the components that bestow weed with its flavours, aroma, and potency. When they’re cut too late, THC degrades into CBN, resulting in a more narcotic marijuana plant.

The best way to know if the trichomes are at their optimum point of ripening is by looking at how translucent they are. Use a magnifying glass: if they look like small transparent dew drops, then the plant still has time to produce more cannabinoids and terpenes. When they start to have a milky appearance, that’s when THC production is at its peak. And when the trichomes are amber, then that’s a sign that THC degradation is significant and CBN is increasing, which can mean that the ideal time for harvesting has already passed.

In order to obtain the greatest psychoactive effects, many growers look for 10 – 20% amber trichomes before harvesting. This offers a good balance between milky and amber trichomes, which translates into a pleasurable and stimulating effect, with certain euphoria, and with a little bodily sensation on the side. If, on the contrary, you’re looking for flowers which produce a relaxing and narcotic effect to promote sleep or relaxation, it is best to harvest when 80% or more of the trichomes have turned amber.

What’s the brown pistil ratio?

This is another key sign that harvest time is near; although it is the stigmas that you should really be looking at. These are the long hairs that grow out of the calyx pistils, which are the reproductive parts of the cannabis flower. In quite a few cases, as the ‘body’ of the bud fattens, the pistils may be scarce or remain a milky colour. Depending on your preference, you might want to wait until the pistils turn orange, red, or brown ― they’ll also start curling up against the buds as they do so.

You can wait to let the plant ripen fully, although you’ll probably learn what the ideal pistil rate is over time. As a general rule of thumb for rookie growers, look for 75% brown pistils before thinking about harvesting.

How swollen are the calyxes?

Swollen calyxes are also an indicator of peak maturity. In the sixth week of flowering, the calyxes start to swell. Growers are often impatient and harvest their plants before the calyxes have fattened enough and bunched together. At maximum maturity, about 90% of the calyxes will have fattened up.

How compact are the buds?

Thanks to the swelling of the pistils, the shape of the buds can also offer some clues as to how ripe the plant is. Look for firm and tight buds as a sign that the plant is ready for cutting.

Have the fan leaves turned yellow?

Another reliable indicator are the changing tones of the fan leaves, which is something that the plants use to facilitate their capture of the sun’s energy and to boost their photosynthetic activities. During the flowering stage, nitrogen gives the leaves their green colour. At harvest time, as nitrogen decreases, the leaves turn yellow and start to fall because the plant concentrates its final energy on the flowers, gradually stopping its absorption of nutrients and the photosynthesis in the leaves.

Have the leaves curled up as well?

As the fan leaves change from green to yellow, they can also curl up and dry. This lack of humidity is actually a natural phenomenon of cannabis plants. They use up less water as harvest time approaches because the plant has already fulfilled its biological purpose: to produce ripe flowers which are now ready to receive the male pollen.

How about the smell?

You’ll also quickly notice that the plant is getting ready for harvest when the flavonoids and terpenoids are fully developed. You’ll easily smell the plant’s scent as you enter the grow room. If the plant doesn’t release much smell, it is safe to say that you need to wait for a few more weeks until these other compounds mature fully. If you harvest too soon, you’ll be getting a reduced potency of the plant’s flavour, which would ultimately be detrimental to the goal of obtaining the best weed possible.

Is there a golden rule for when to harvest?

Finally, one of the best tips that any experienced grower could give you is “When you believe it’s time to harvest, wait another week!”

While this is true, it is also possible to harvest too late. The crux of the matter is that it’s infinitely better to harvest a week later than a week too early. Generally speaking, when you harvest ‘over-ripe’ marijuana you can still get high, but its effect may be a little more couch-locking. That’s why it’s always good to experiment with all these factors to discover the best point of maturity to meet your personal needs.