When is the Exact Time to Harvest Cannabis Plants?

After several months of observing your buds and waiting for your cannabis plants to mature, there comes a time when you have to decide to harvest. It isn’t as easy to choose the ideal time as you might think, and in the excitement of harvesting your cannabis for the first time, you could cut it down far too early and miss out on the full effects of the herb.

The flowering time of cannabis varies depending on the strain, and for most growers, there are two methods of determining when your plants are in peak harvest. There is the pistil method and the trichome method. The former only requires your eyes, whereas the latter involves the use of a magnifying glass such as a jeweler’s loupe.

Harvest timing is arguably the trickiest aspect of growing marijuana for newbies. If you do it too early, you reduce the overall potency of your cannabis. If you leave it too late, your weed will have an excessively strong taste and an unwanted narcotic effect. In this guide, we provide you with details on the best time to harvest, as well as information on what you can expect during the process.

Best Time to Harvest Your Cannabis Crop

After several weeks in the flowering phase, your marijuana plant will begin to decline in health. Once most of the pistils (the hairs found on the buds) have turned red, it is already too late, and the marijuana you harvest will lack the psychoactive effects you desire. During the latter stages of flowering, the trichomes on your plants become amber.

They ultimately reach their peak level of THC, and if you haven’t already harvested by now, the psychoactive cannabinoid starts to break down after being exposed to UV rays and oxygen. Over time, the THC becomes cannabinol (CBN), and while this particular cannabinoid has some apparent medicinal properties, it lacks the ‘high’ provided by THC. Indeed, CBN is known for its sedative properties, so it is ideal if you have insomnia and need a night time smoke.

As a rule of thumb, indica plants are ready for harvesting after 8 weeks, while sativas need 10 weeks. Autoflowers require 10 weeks in total from seedling to bud. However, you can’t take these recommendations as a guarantee, which means you should use one of these two methods of determining the right time to harvest.

The Pistil Method

When the majority of the pistils on your plants are white and straight, it is far too early to harvest, and you probably have to wait several more weeks. Once you reach the point where 50% of the pistils achieve a brown/reddish color (and begin to curl in), you are very close to harvesting time.

Once 60% of the pistils have darkened, you can harvest for the highest amount of THC. Once 70-75%+ of the pistils darken, it is time to harvest if you want marijuana that offers a calmer effect. If you leave it too long, your marijuana will lose most of its psychoactive properties.

The Trichome Method

Unless you have Superman’s vision, it is impossible to do this method with the naked eye. We recommend purchasing a handheld microscope with a range between 30x and 100x. You will need it to check the trichomes (resin glands) found on your plants’ buds and adjacent foliage. Ideally, you will use a microscope that illuminates the foliage, so you receive an unshaded view of the trichomes.

In case you weren’t aware, trichomes are the crystals you see growing on the buds and leaves. They are the reason why your marijuana is so sticky, and they play a major role in the potency of your crop. You’re looking for trichomes that resemble miniature mushrooms; in other words, resin glands with a little ball on top.

Once there is a large number of ‘mushroom’ trichomes, your marijuana has effectively reached maximum potency. Pay attention to color as well. Plants with clear trichomes are not ready for harvest, whereas weed with milky white or amber trichomes is primed for harvest. If the trichomes are all amber, you’ve left it too late!

Here is a list of magnifying tools you can purchase for the trichome method:

  • Jeweler’s loupe: Although it isn’t a hi-tech piece of equipment, a loupe should offer enough magnification for an accurate reading on whether your plants are ready for harvest. You can find loupes for under $20, but most of them only offer a magnification level of 40x or less.
  • Handheld magnifier: This is probably the best option because it gives you a mixture of quality and value. It offers a greater degree of magnification than a loupe, and while it is typically more expensive, it should still be comfortably within your budget.
  • Digital microscope: This is clearly the most expensive option, but it also provides you with the most accurate reading. There are numerous digital microscopes with a magnification of well above 100x. However, you’re really paying for convenience, because with a digital microscope, you can connect it to your computer to see the images on the screen.

What is the THC Level in Your Cannabis at Harvest Time?

Overall, the ‘perfect’ time for harvesting depends on what you’re looking for. For instance, if you want marijuana that acts as a sedative, wait until the pistils of the plant are almost entirely amber. That way, you will have weed with a high CBN content. However, for the highest level of THC, you should consider harvesting when 60%+ of the pistils have changed color.

Alternatively, wait until the resin on your plants has darkened in color ever so slightly. For bud with the highest level of THC, look at the trichomes through your magnifying device. When you see clear trichomes, it is a sign that the buds are still developing. Assuming you have your crop close by, it is best to monitor the trichomes as often as possible. This is a very exciting time because your plant is very close to reaching maturity.

Here’s a quick guide to determining the optimal THC content based on the pistil and trichome methods.

Checking for THC Content via the Pistil Method

  • 0-49% of Pistils are Brown: Now is not a good time to harvest because your marijuana is nowhere near maximum potency.
  • 50-69%: Your plant is still not at its peak THC level, but you have the option of harvesting now for a mellow high and light taste.
  • 70-90%: Once you reach this range, it is definitely time to harvest because your marijuana is as potent as it is ever going to be! Most growers suggest that the ‘sweet spot’ is 75-80%, but any time after 70% and below 90% will result in high-quality weed.
  • 91%+: Your plant is now past peak THC content, and the cannabinoid has already begun degrading into CBN. Marijuana left this late will have a heavy taste and narcotic effect that’s sure to leave you drowsy.

Checking for THC Content via the Trichome Method

  • Transparent color: Your plant is not ready. If you harvest at this stage, you will have a lower yield and decreased potency.
  • Cloudy color: This is the best time to harvest. Cannabis plants with mostly milky white or cloudy trichomes contain the most THC and provide an energetic and potent high.
  • Amber/Cloudy: The plant is probably slightly past its most potent stage, but you’re still rewarded with a powerful cerebral and body high.
  • Amber Color: The plant is past its peak, and the high you receive now is mainly sedative.

The Right Time to Harvest Cannabis – Our Recommendations

As you have probably ascertained from reading this guide, there is some disagreement over the precise time to harvest your cannabis plants. Not only is growing cannabis an intensely personal experience, but it is also a process that can only improve through practice. There is no single ‘gold standard’ for either the pistil or trichome method that applies to all marijuana strains.

An increasing number of growers are experimenting with higher CBN products, because this cannabinoid has been linked with pain relieving properties. Although a high CBN marijuana strain will make you feel drowsy, it has been described as a pleasant experience by some users. For best results, harvest when your marijuana plants have slightly exceeded their peak level. By doing this, you receive a strain with CBN as well as THC.

Here is a quick summary of when to harvest marijuana and what you can expect at each stage.

  1. Your plants are not ready for harvest if the pistils are white and sticking up and if the trichomes are still clear. If you make the mistake of harvesting at this stage, you will be punished with a low yield and decreased potency.
  2. Once your plants have stopped growing new pistils, and at least 40% of them have changed color and curled in, you are officially at the very beginning of the harvesting window. It is still too early, but at least you haven’t ruined your hard work. Ideally, you will wait a week or so, but we recommend monitoring your plants daily from this point.
  3. When 50-70% of pistils have darkened, and the trichomes are changing color, you are extremely close to peak THC content.
  4. Once 70+ of the pistils have changed color and curled in, AND the majority of trichomes have a cloudy color and little balls on top, you are at the precise right moment for harvesting if maximum potency is your goal. Don’t waste any more time because your plants will start to degrade rapidly from this point onwards.
  5. There are a few sativa strains with trichomes that don’t change color. If this happens, wait a little while, but if they still don’t change color, you should harvest before the quality of the bud declines.
  6. Once 80%+ of pistils have darkened, and the trichomes are part amber, part cloudy, your plant is past peak potency. Harvest now or else you will end up with a high CBN content.
  7. If almost all of the pistils have changed color and the trichomes are grey or withered, you have missed out on the harvest window. You end up with low-grade weed if this happens but on the plus side, it normally takes up to four weeks from the beginning of the window for this to happen.
  • For a cerebral high: Harvest at step #2 when 40%+ of the pistils have changed color, and at least half of the trichomes achieve a cloudy color.
  • For potent weed: Wait until step #4 when 70%+ pistils have changed color, and the cloudy trichomes look like mushrooms. At this point, your marijuana has the highest possible amount of THC.
  • For a relaxing high: Wait until step #6 when some of the trichomes are amber, and over 80% of the pistils have turned brown. Generally speaking, the more amber the weed, the more relaxing the high. If you wait too long, however, you end up with a strain that contains little THC and a lot of CBN.

Choosing the ideal harvesting time is extremely difficult and represents a significant challenge to a first-time grower. Above all else, please remember that you’re allowed to cut off little pieces of the plant if you suspect that harvest time is close. Sample the pieces you take to determine your preferences. If you get extremely high from the clippings, it is definitely a good time to harvest the rest!

The main enemy of the new grower is excitement. It is understandable that your desire to sample the produce is overwhelming, but you have to be patient. There is no point spending months carefully tending to your plants if you decide to ruin everything by harvesting too early.

Although it is not an exact science, it isn’t as difficult to pick the right moment as you think. Once the pistils and trichomes begin changing color, it is time to monitor your crop closely. Check on it daily and adhere to the guidelines above. Cut your weed down for curing and drying once your plants have reached peak potency. Alternatively, harvest earlier for a mellow high or later for a relaxing one.