When to harvest cannabis for the perfect buds

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Over the last few months, you have poured all of your effort into cultivating your prized cannabis plants, and now, it’s time to enjoy the fruits of your labor. However, the very last hurdle to overcome is harvesting. Harvesting is the stage where many first time growers, eager to test their bud, rush the final stages. However, it is vital that you complete the full process and clearly understand when to harvest cannabis if you want bud that is both potent, tasty and stays fresh while being stored. Cannabis harvesting is a four step process:

  • Assessing when the buds are ripe to begin harvesting
  • Cutting down the plant and trimming the bud
  • Drying the cannabis bud
  • Curing the cannabis bud

Harvesting cannabis at the right time is key to maintaining your buds’ potency, flavor, appearance and weight. So, what is the right time to harvest cannabis? Is there a way to determine when cannabis plants are at peak ripeness?

When to harvest cannabis for high THC weed

Yes. The most precise way to detect when a plant is at its peak potency is by inspecting the trichomes’ color and shape. Once these hair-like appendages turn milky white with a rounded top, THC and other cannabinoids’ levels are at peak levels. 

With the right timing, you will be guaranteed an impressively potent harvest each and every time. This piece focuses on the first part of the harvesting process: identifying when the buds are ready to harvest. It is the first piece in a series of articles covering all aspects of the harvesting process, such as flushing, cutting & trimming, and drying & curing cannabis plants. Read on to find everything you need to know about the different trichome colors, what they represent, and how you can achieve various effects (stimulating or sedating) depending on when you harvest your bud. 

What do trichomes look like when ready to harvest?

When you inspect a cannabis plant, you will spot numerous white hair-like protrusions around the stems, leaves, and buds. These tiny sticky appendages are referred to as trichomes. They start appearing as soon as cannabis plants enter the flowering phase. They serve multiple roles, such as protective mechanisms against insects, animals, UV light, and pathogens. 

More importantly, trichomes are the primary producers and storage of cannabinoids (including THC and CBD) , terpenes, and flavonoids. Initially, trichomes appear like glass-like appendages, which turn to milk white and amber appearance as the plants reach maturity.

Below we will explain in full detail precisely when the perfect time to harvest is and how to make this assessment yourself.

How can you tell if trichomes are ready for harvest?

First, you inspect the shape of the trichomes: do they resemble miniature mushrooms (rounded top supported by a stick-like body)? At this point, the top is filled with resin, and the buds are ready for harvest. 

Secondly, look at the color of the trichomes: are they clear, white, or amber? Clear trichomes indicate unripeness, so the buds are at their lowest potency levels. White trichomes indicate peak potency. At this point, THC levels are at the highest they will be. This is an excellent time to harvest for a stimulating, cerebral-centered high. 

Amber trichomes indicate THC degradation as the plants are past their maturity stage. When THC is exposed to UV lights and oxygen, it breaks down to CBN, a cannabinoid known for its potent sedating and anti-anxiety properties.

How do you know if you have overripe buds?

Once a majority of trichomes are amber (80% or more), the plants are way past their ideal harvest date. The overripe trichomes become brittle and may crumble on the touch. At this point, most of the THC will have degraded, and the buds will lack potency, flavor and smell.

Side note: In addition to observing trichome shape and color, you can use other indicators to gauge the maturity of the cannabis plants – However assessing trichome appearance is the most accurate way to judge the ripeness of your cannabis bud. Other indications that can be used in addition to this are:

  • The change of pistil color from white to orange and brown. Buds are normally ready for harvest when around 70% of the pistils turn color. The pistils also tend to curl inwards as the planets approach maturity. However, this is not a 100% accurate measure of ripeness on all strains.
  • The fan leaves become yellow, curl, dry, and eventually begin to fall off.

How to harvest marijuana according to trichome ripeness?

Unfortunately there isn’t a one size fits all approach of finding when to harvest cannabis. Typically, Indica strains stay in the flowering phase for eight weeks, while Sativas take up to ten weeks. However, this differs from strain to strain, depending on the parent genetics, a cultivator’s preference, and the growing conditions. As you purchase your seeds, ensure you learn about their preferred growing conditions, training techniques you can try, and most importantly, the weeks it takes to flower. 

As you approach the plants standard flowering time, you should start to inspect the buds more closely by analysing the trichomes so that you are able to spot the signs that your cannabis buds are at their peak level of potency. To do this you will need a tool that allows you to magnify the buds and their trichomes. You can use tools such a jeweler’s loupe, magnifying glass, microscope, or a even a high quality camera phone. 

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Magnifying Glass: These devices are easy to acquire and deliver quality and value for money. The best magnifier for trichome inspection range between 30X and 60X. Many cultivators prefer these since they provide a very wide viewing angle. However, the limitation is that they can’t zoom in close. 

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Jeweler’s loupe: This gadget is similar to a magnifying glass but is smaller and can provide more detail. Jewellers loupes are used by jewellers to asses the clarity of diamonds and other precious gems, they are probably the cheapest option to buy online. The best jeweler’s loupe for viewing trichomes should be light, portable, has a sturdy frame construction, and has a magnification of up to 40X. 

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Camera Phone: Nowadays most modern camera phones have cameras that are good enough to be used as a magnifying glass for assessing trichome ripeness. If you have a phone with a powerful camera, then you might not need any other device to view the trichomes. Simply use the camera program on your phone and zoom in until you get a clear view of the trichomes. The positives to using a camera phone is that you can take photos and save them for later assessment and comparison.

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Microscope: Pocket microscopes are the most expensive pieces of equipment on this list, however they provide the most clear and powerfully magnified image (up to 100X). Although more expensive compared to the other options mentioned above, they are a worthy investment for a serious full-time cannabis cultivator. 

NB: when it comes to harvesting marijuana, a cultivator can harvest according to peak potency or by the desired effects.

Different methods to asses when to harvest marijuana

While the most accurate way to asses when to harvest marijuana plants is to continually monitor the appearance of its trichomes, there are lots of other indicators that are more obvious to the naked eye that you can use as well. Once you start to see some of these signs, it is a good idea to also use a magnifying tool to view the trichomes in more detail, as this is the best way to pin point that perfect 2-3 week window.

Harvesting marijuana based on leaf changes

As the plant matures, its water and nutrient absorption rates significantly reduce. As a result, you may notice the fan leaves turning from green to yellow. Another sign is the curling of the leaves, this is an indication that the plant may almost ready for harvest.

Harvesting marijuana Based on calyxes

As the plant nears maturity, the calyxes will become swollen. Do not harvest based on this factor alone, as it can also indicate a hermie. Ensure you look at a combination of other indicators before harvesting.

Harvesting based on pistils

The pistils or hairs will turn from amber or orange to brown as an indicator of plant maturity. 

Note: You will need a moderately strong magnifying glass or a smartphone camera magnifier to inspect all the parts of the bud mentioned above. 

Harvesting marijuana based on the time of the year and weather changes

While not the best method, if you are looking for peak potency, sometimes, the location and weather patterns can determine when to harvest cannabis plants. Cannabis plants, particularly sativas don’t handle cold weather very well. If you are growing outdoors, depending on what part of the world you are in it could be wise to harvest slightly earlier to avoid cold weather potentially damaging your harvests. Below are the typical harvest periods for cannabis crops depending on region.

LocationIdeal harvesting time
Northern Hemisphere September or November 
Northern CaliforniaLater October to the middle of November
Pacific Northwest Mid-October to early November 

Based on the type of strain

In general, Indicas take around 8 – 9 weeks to flower and reach maturity. On the other hand, Sativas take a bit longer, budding for up to 12 weeks before they become harvest-ready. Autoflowers do not depend on light to switch from one growth phase to another. Instead, they transition automatically and grow from seed to maturity within around 8-10 weeks. Check the breeder or seed banks guidance on flowering time for that particular strain and keep a record of the plants’ progress it grows. Track the number of weeks they spend on one growth stage before transitioning to the next. Having knowledge of the genetics of the strain you have cultivated can help you determine the ideal time to harvest and will massively help you perfect your technique if you grow that strain again.

Factors that can lead to early harvesting 

Sometimes, things do not go as planned. Circumstances change, forcing us to find a way to make the best of a bad situation. While you may plan to harvest your cannabis at the right time, some factors may prevent you from doing so. These factors include 

Freezing weather – exposure to frigid weather is tolerable for about 3 hours. After that, the extreme cold will destroy your plants. 

Rain – prolonged periods of rain increase the moisture content of your buds, which can lead to mold formation. Building a temporary shelter for your plants can help the rain at bay. However, the increased humidity may still lead to damaged plants. At this point, it’s best to harvest to save your crop. 

Bud rot – undiagnosed bud rot can quickly destroy your plants. If some plants have bud rot and you suspect the remaining may be affected, harvesting is the best option.

Frequency of harvests per annum

Harvesting cannabis indoors – The cultivator determines the number of harvests they want in an indoor setup. The grow tent/ room provides optimum growing conditions that support multiple harvests per annum. Autoflowers, in particular, take 8-10 weeks to grow, meaning one can have as many as five harvests in a year. 

Harvesting cannabis outdoors – The outdoor environment restricts the number of harvests a grower can have per annum. The best growing season is from spring to fall for photoperiodic strains.

Tricks on how to have multiple outdoor cannabis harvests

Autoflowers allow more harvests

Autoflowers grow from seed to being harvest-ready within 2-3 months. Additionally, due to the Ruderalis genetics, the plants are very resilient and resistant to unfavorable weather, molds, and pests. Autos are easy to grow, and the bonus is that they don’t depend on light to transition from one growth stage to the next. With autoflowers, one can manage two growing seasons – March/April to June/July and June/July to October/November.

Limit the plants’ access to light 

If you grow photoperiod plants, manipulating the light cycle can help with multiple harvests. Light deprivation is a technique that involves placing a tarp over a greenhouse to cut off light supply to the plants. The cannabis plants respond to this by transitioning to the flowering stage earlier than they were supposed to. As a result, the plants take less time to mature, giving way to more harvests. 

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outdoor cannabis grow under polytunnel

However, this method requires that you have a greenhouse, a tarp, and multiple other equipment. Additionally, you will need to put and remove the tarp every day, following the same schedule. If the plants get 12 hours of sunlight today and 14 hours tomorrow, they may affect the quality and quantity of your yield. Let’s now dive into the harvesting process. Possibly the simplest and cheapest way to do this is to use a polytunnel (image above) with a tarp pulled over the top during the dark periods.

Harvesting marijuana by potency 

The best time to harvest marijuana for potency is when 70% of the trichomes are cloudy and have a rounded top. At this point, the buds are at peak potency. Since the trichomes mature at different paces, it is impossible to have all the trichomes turn milky white simultaneously. If you wait longer, some of the trichomes will begin to turn amber, which translates to lowered potency levels. 

Harvesting marijuana by effect

Did you know that harvesting marijuana buds at different stages can produce varying effects? Harvesting buds earlier on tends to produce stimulating effects and waiting for longer leads to relaxing effects. If you are looking for a specific effect, here is how you can determine the right time to harvest. 

Stimulating effects 

When the trichomes are 50+% milk cloudy, the resulting effects are euphoric, energetic, and stimulating. For medical consumers, these effects help with depression, stress, mood fluctuations, and PTSD. 

Balanced effects 

For a good balance of physical and cerebral effects, harvest when the trichomes are 70% cloudy and 30% amber. Most cultivators prefer harvesting at this point. The buds will produce a stimulating high coupled with mild relaxation. 

Relaxing effects 

If you aim for more relaxing than cerebral effects, harvest when the trichomes are 50% to 60% cloudy and 40% to 50% amber. At this point, consumers will experience potent relaxing effects and couchlock. 

Sedating/narcotic effects 

Waiting until more than 60% of the trichomes are amber leads to a sedating/narcotic effect. The taste becomes unpleasant, and some of the trichomes may begin turning black. Waiting this long is not recommended, as harvesting past a plant’s prime interferes with the overall potency, quality, flavor, and aroma of the buds. 

Outdoor cannabis harvest

When growing outdoors, cultivators have limited control as to when they can harvest their cannabis plants. While observing trichomes is a viable option, one has to be very mindful of the weather. Cold and wet conditions compromise the quality of the harvest. Consequently, if the cold or rainy season is fast approaching, the best option is to harvest early. 

Trichome harvest chart

Below is a trichome harvest chart that you can use to compare the trichomes of your cannabis plants with. There are more than one type of cannabis trichome, however the trichomes that we want to keep an eye on that will give us an idea of bud potency is the capitate-stalked trichome. Circled in the first image below, the capitate stalked trichome is the primary storage area of a plants THC, CBD and any other cannabinoids found within cannabis plants. By assessing capitate stalked trichomes using the methods explained above you will be able to pin point precisely when the best time to harvest your cannabis plants is for optimum potency.

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Capitate-stalked trichomes on a cannabis bud – these contain most of the plants THC and other cannaboids
when to harvest cannabis, when to harvest marijuana, trichome harvest chart, over ripe buds, under ripe buds
Trichome ripeness chart can be used to harvest cannabis according to potency

Understanding the trichome harvest chart

Clear Trichomes: As you can see from the first image, the trichomes appear clear and glass-like in appearance, this shows that they are under ripe buds and not yet ready for harvest. At this stage THC and terpenes are still being produced and therefore potency is likely to be quite low and the bud will be lacking in flavor and smell. However, keep checking the trichomes on each plant daily as they can change quite fast.

Cloudy Trichomes: If you continue to check the appearance of trichomes you will notice that they gradually turn a cloudy/milky color. This means that the buds are beginning to enter their window of ripeness. Once the majority of the buds have a cloudy appearance they can be harvested, however it is down to personal preference at this point exactly when you decide to do so. Trichomes that are mostly cloudy tend to be higher in THC, are at their peak potency and provide an energetic high. Left a little longer until some of them begin to turn amber and they give users a more sedative couch locked effect. Trichomes tend to stay their cloudy/milky color for around 2-3 weeks before turning amber.

Amber Trichomes: As trichomes begin to turn amber it is a sign that the bud is nearing the end of its window of ripeness, once around 15-20% have turned amber, this is when users preferring an energetic and slightly euphoric high should harvest, The amber appearance is an indication of gradual degradation within the trichome, some users prefer to allow around 50 – 80% of their trichomes to turn amber because this provides a more relaxing sedative effect.. If you want to allow your trichomes to turn amber, keep checking them every day and be careful not to overcook it, once they go beyond the 80% amber mark I would say that they are over ripe buds and the taste, smell and potency will begin to degrade.

Understanding under and over ripe buds

Using your handheld microscope, magnifier, camera phone, or jeweller’s loupe, you can keep track of your trichomes’ ripeness to determine the ideal harvest time. Below is a clear explanation of the different stages of trichome ripeness (under ripe, ripe, and overripe trichomes). 

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What do under ripe buds look like?

Under ripe buds when magnified will have trichomes that appear as small, clear, and colorless protrusions that increase in size and density as the plant matures. During the development stage, the trichomes remain clear and glassy, meaning there is no production of phytochemicals. Trichomes with a clear, glass-like appearance are an indication of under ripeness. 

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What do ripe trichomes look like?

Ripe trichomes are cloudy as opposed to being transparent. As mentioned before, trichomes mature at different stages, so it is possible to spot some amber and clear trichomes at this phase. 

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What do overripe buds look like?

When the trichomes shift from mostly cloudy to primarily amber, they are well past their prime potency and are considered overripe buds. At this point, the effects change from stimulating and relaxing to sedating and narcotic. 

When should you start flushing your cannabis plants for harvest?

When is the right time to start flushing your cannabis plants, and when should you stop watering them before harvest?

The flushing stage is made up of two parts, however, lots of growers differ in their opinions on this so their isn’t one right way to do things. The first stage is flushing where you stop using all nutrients, and then after that you stop watering completely, for just a couple of days before harvesting your bud.

For most cultivators, the best time to flush cannabis plants is two weeks before the scheduled harvest day. This helps to remove any leftover nutrient build-up within the plants and soil. During this time, the plants use up any nutrients and supplements in their system and it is flushed out with water, leading to a smoother and more satisfying smoke.

How do I know when to begin flushing?

This comes with practise and as you grow more cannabis plants you will get better at assessing precisely when to begin flushing your cannabis plants. However, don’t overstress as growers generally flush from as little as a few days all of the way up to two weeks. I tend to prefer to start flushing 1-2 weeks before harvesting, however, it is important that you do not extend your harvest date too much just to accommodate your flushing period as you could end up with over rip buds that will lack potency.

To asses when to begin flushing your cannabis plant, keep a close eye on the appearance of the trichomes, as soon as you notice that they are beginning to turn from clear to cloudy, this is normally an indication that you have around two weeks left before they will be ready to harvest. At this point you can begin flushing with just water and no nutrients. However, keep assessing the color and appearance of the trichomes, some strains mature faster than others and you may only have a week before your plants are ready for harvest, in which case you can just flush for one week instead of two.

When should you stop watering before harvest?

Not all growers do this, however the idea behind withholding water before harvesting is to trick your cannabis plants into thinking they are entering a drought. This triggers a stress reaction from the plant and causes it to divert all of its resources into reproduction, the result is bigger and fatter buds. There is not a huge amount of research into this theory, however, from experience I prefer to stop watering the plants completely 2 to 3 days before harvesting.

Withholding water also allows the soil and plant to begin drying out which will make the next stages of harvesting your cannabis plants much easier.

What are the next steps after harvesting cannabis?

Once you have assessed the perfect time to harvest your buds and flushed your cannabis plants, the next stage to the harvesting process is to cut your plants down and begin trimming up your buds before drying them out.

There is more than one way to simply trim your cannabis buds, some commercial growers prefer to hand dry entire plants (a lot of space is required to do this) while others prefer to painstakingly trim the buds one-by-one using scissors (this is the method I prefer). Read our next guide on trimming cannabis bud for a full debrief on this subject.

Notes:

  • Tanney, C.A.S., Backer, R., Geitmann, A. and Smith, D.L. (2021). Cannabis Glandular Trichomes: A Cellular Metabolite Factory. Frontiers in Plant Science, 12. doi:10.3389/fpls.2021.721986.
  • Sutton, D.B., Punja, Z.K. and Hamarneh, G. (2023). Characterization of trichome phenotypes to assess maturation and flower development in Cannabis sativa L. (cannabis) by automatic trichome gland analysis. Smart Agricultural Technology, [online] 3, p.100111. doi:10.1016/j.atech.2022.100111.

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