Multiple phases of a trichome explained

When it comes to cannabis, the trichomes are the most important part of the plant. They contain all cannabinoids and terpenes so they are responsible for the taste, aroma and effect of your cannabis. Without them, cannabis would be “useless”. The colour of trichomes are able to tell you many things about the specific properties of your cannabis and at what moment you should harvest. Their colour changes due multiple phases of their growth.

Along the flowering phase, these trichomes will evolve and change their amount of specific cannabinoids in them. also the combination of certain cannabinoids changes over time.

For example: At first, trichomes will be filled with THCA and some other cannabinoids. However if you wait long enough, THCA will evolve to CBN changing the cannabinoid spectrum of your trichomes.

In this article, we will talk about the multiple stages of a trichome and what they mean! 

The first phase…

In the vegetative phase of your plant, you won’t see any trichomes as they only turn up once your plant is flowering. Trichomes will show up on the buds and the leafs around them. After you have switched to flowering it takes some days before you see the first trichomes coming out of the plant’s surface.

We call these fresh trichomes “empty”. This means that they don’t contain any cannabinoids, terpenes or flavonoids. However they quickly start to fill up with these compounds, so this moment of them being “empty”is very short. The transparancy will stay for a while, even when there are cannabinoids present.

The first trichomes are growing on leafs/calyxes. As you can see they are all clear and wont contain much cannabinoids/terpenes. At this moment, it will take weeks before the cannabis is ready to harvest.

Find out: How to determine the perfect harvest moment based on trichome colour!

In the first phase, there wont be many trichomes as you can see, later on this surface will be filled with trichomes. This is a perfect picture of the beginning phase of the trichomes.

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The second phase:

After a while, your calyxes, buds and “sugar-leafs” will be covored in trichomes. This is the moment they start to fill themself up with multiple cannabinoids and terpenes. at the beginning, it’s mostly THC that will fill and colour the trichomes (combined with some other cannabinoids). THC will give the trichome a bright white colour. So you will slowly see a transition from transparant to white. This process could also take up to a few weeks and not all trichomes will colour at the same time. With a magnifying glass this will be clearly visible. 

Next to cannabinoids like THC, there are also terpenes that will start to evolve inside the trichome. These terpenes will take care of the smell and taste of the cannabis. Different terpene profiles will offer different odors. In this phase, your growroom will start to smell strongly!

Slowly, the trichomes will start to turn white. Especially in their heads you will see the difference in colour. The white colour will increase more as THC is filling the them up. However the plant on this picture is still far from ready (some are still transparant)!
As the weeks pass, you will see more/all trichomes turning bright white. These are THC-rich trichomes! You can also see the pistils getting brown, which means everything is going well!

Once these trichomes are filled with THC, you might think it’s time to harvest. However, most growers still wait a few weeks. THC might be at it’s top levels, but other cannabinoids still need to evolve to get the desired effect for consumers. If you would harvest when trichomes are only white, you will only get a light “head high” without any “couch-lock” (numb feeling in your body). This is not what most consumers want. We recommend to wait a little longer…

The third phase

If you wait for another few weeks, other cannabinoids are able to increase or evolve giving a whole different high. The most important aspect is that THC will slowly turn into CBN. The longer you wait, the more this happens. This means that the cannabis will turn more physically after consuming and giving you a numb/heavy feeling in your body. Good for sleeping and relaxing.

This will actually be visible in the trichomes! When this happens, you will see the white slowly turning into an amber/brownish colour. The trick is to find the right balance based on your own wishes. We always go for this rule:

  • Once 20-30% of white trichomes have turned into amber, it’s time to harvest! 

Always make sure you look for these percentages based on the trichomes on the calyxes, not on the sugar leafs (These often turn amber more quickly).

This is only really visible when using a magnifying glass or macro lens on your camera. It’s important to keep a very close watch on your trichomes in this phase as they might turn amber quickly and you don’t want to be too late. In the next photos you will see the amber trichomes very clearly:

Here you can clearly see the first white trichomes turning into amber. The best way to look at it is by watching the trichomes heads. This plant is not ready yet, it takes a little longer before 20-30% is amber coloured.
This purple strain clearly shows more amber trichomes. The amber is more bright and stands out of the rest. At this phase, around 25% has turned amber which is a great moment the chop her down! The CBN levels are high enough now to leave you with a “perfect” high.

In the end, it’s your own choice when to chop her down. Some people may like a more energetic, head-high. They have to harvest a little earlier. However most growers/consumers agree that it’s nice to have some amber trichomes (So higher levels of CBN) in their cannabis.

Questions, Additions or anything else to say? Leave a comment below!

8 thoughts on “Multiple phases of a trichome explained

  • May 28, 2021 at 1:18 am

    Thanks for the very informative article about the multiple trichome stages.

    Cheers and stay safe!

    • June 7, 2021 at 9:49 pm

      No problem, always happy to help!

  • June 10, 2021 at 11:15 am

    thanks for the article it has really helped me understand what everyone i watched meant but i still have one question when they are 20-30% amber/brownish and you cut the plant will they still keep turning amber/brownish or will they right away stop changing?

    • June 13, 2021 at 11:58 pm

      It’s possible that they continue to develop for a day or so, but not long enough to really change the colour.

  • June 11, 2021 at 1:05 am

    Great explanation and pictures!

  • October 5, 2021 at 3:50 am

    Loved it…..Just what I wanted to know. Thank you

  • October 5, 2021 at 4:34 pm

    I have a outdoor indica , black domina that won’t finish. It’s now October 6 and very few milky tricombes , mostly clear and no swelling as of yet , I have another week before it’s gets frosted here so I have to pull middle of month , do you think they will turn by then or just chop before frost ? Thanks dan

    • October 5, 2021 at 9:43 pm

      Well some strains are known to bloom and finish later in the year then others, however these are often more cold-resistant. It could also depend on where you live: How many light-hours a day are you dealing with in your area? The only tip I could give is to shorten the light hours of your plant drastically by placing them inside/in the dark. Let’s say the sun comes up at 07:00 and at 20:30 it’s fully dark, in that case you’d have 13,3 hours of light. Try to minimalize it by putting your plants in dark at 18:30/19:00 so the “night” becomes longer.

      Another reason this problem could occur is due the moonlight. If the moonlight shines very bright in your area and lights up your plan, it could give some problems and slows down the flowering of your plant. Long and very dark nights will increase the speed of flowering (the plants think it becomes winter and puts al his energy in flowering/producing cannabinoids in trichomes.

      If you don’t have to option to move your plant around, you could work with tarpaulin to create some kind of cover to keep out the moon/sunlight.

      Good luck!


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