Cannabis trichomes are the resin glands of marijuana plants. As the cannabis plant goes through different stages of the maturation process, the trichomes change colour from clear trichomes to mushroom-shaped milky or white trichomes, and eventually, amber. How long do trichomes take to turn amber?

It takes 2-5 weeks for trichomes to turn amber from being clear. Trichomes take one to two weeks to turn milky from clear, and another one to two weeks to change from cloudy to amber. Indicas and hybrid strains tend to take longer to turn amber. 

Milky trichomes mean the marijuana plant is producing a high amount of tetrahydrocannabinol or THC. Cloudy trichome tips darken to amber, signalling that the mature plant is nearing the end of its lifecycle and the cannabinoid biosynthesis (1) is producing higher levels of cannabinoids or CBD. This usually happens one or two weeks after flowering.

Keep reading so you don’t miss out on any information about this topic, including possible reasons for your trichomes not turning amber.

How Fast Do Trichomes Change Color?

The trichomes of a cannabis plant change colour as the plant grows and matures. Every breed of marijuana plant is different, and the length of its lifecycle will vary depending on environmental conditions and whether it is Indica or Sativa. 

Trichomes of a plant in the flowering stage begin to develop and then change colour over the next few weeks until the desired level of THC is reached for harvest. Generally, trichomes change to cloudy one to two weeks after flowering. When the trichomes are milky, they will begin to turn amber about two weeks later.

The colour changes of the trichomes can be observed with a strong magnifying glass or microscope. Changes in trichome colour tell the grower when the plant is ready for harvest. Some growers use good lighting, exact temperatures, and plenty of plant supplements to increase the growth of trichomes, but the timing of the trichome colour change depends on the strain of the cannabis plant.

How Long Do Trichomes Stay Milky Before Turning Amber?

Trichomes will stay milky for about two weeks depending on the strain of marijuana. When your cannabis plants have reached the flowering stage, the trichomes on your plants are clear. Over the next one to two weeks, the trichomes will develop stalks tipped with mushroom-like heads or “capitates” that are milky and opaque. Cloudy trichomes will mature for another two weeks before turning a dark red, orange, or brown “amber” colour. At this stage, you’ll have amber trichomes.

How Many Trichomes Should Be Amber?

The number of trichomes that should be amber for harvesting depends on the strain of the marijuana plant and the potency effects desired. Trichome colour is considered the main indicator of THC or CBD potency (2), giving the grower a good idea of where the plant is in the maturation process. 

Growers often disagree on when is the perfect time to harvest. Some say that for Sativa strains or hybrid plants, about 30 percent of the cannabis trichomes should be amber before clipping. Cultivars of Indica plants may choose to harvest later when the resin glands are mostly amber, as it takes longer for Indica plants to mature. Indica strains with large leaves produce more trichomes than Sativa strains, so these trichomes are easier to see to monitor changes.

If the marijuana plant is being harvested for a psychotropic THC effect, the time to harvest is when the trichomes are cloudy, and the THC production is high. This results in a euphoric effect but can also bring on dizziness and intense sensations. For a medicinal, body effect and greater potency of cannabinoids, wait until more of the trichomes have darkened.

Will My Trichomes Ever Turn Amber?

Most cannabis plants have trichomes that turn amber as it matures. Two weeks after your plants reach the flowering stage, you should see that clear trichomes have developed, and some of the trichomes are turning cloudy or milky. As the cannabis plant grows, those cloudy trichomes will start to turn darker. One month after flowering, the milky resin glands should be darkened to amber during harvest time.

Sometimes trichomes are too small to see without magnification, especially on a Sativa strain which has the smallest, bulbous trichomes. Some growers suggest using a magnifying glass, jeweller’s loupe, or microscope to see colour changes in the tips of the trichomes during the different stages of the plant’s development.

Why Are My Trichomes Not Turning Amber?

Reasons why the trichomes on your marijuana plant are not maturing into a dark or “amber” colour:

• You may have started with bad seeds. The strain or variety of your plant can be inferior due to cheap seeds often found for sale on the internet.
• If you are cultivating a strain of cannabis with a long growing season, the plants may show a low percentage of amber-turning trichomes before the plant goes to seed. It is possible to miss the perfect harvest time (3) if you are counting on the trichomes to tell you when to clip.
• A cold environment can slow down or stop the trichomes’ development and the progression of the colour changes that come with maturation.
• Starving your plant during the flowering stage can stunt any further development of buds, terpenes, trichomes, and cannabinoids.
• Some marijuana plant strains do not have trichomes that turn amber after the cloudy stage, including wild strains where the seed has been harvested from random, outdoor plants.

What Makes Trichomes Turn Amber?

Colour changes in the trichomes of a cannabis plant indicate the level of maturity. A young marijuana plant grows small clear resin glands that grow and change to a milky or cloudy capitate-stalked trichome. To some growers, this shows that the plant is a few days away from harvest. As the trichomes turn amber, the cannabidiol or CBD levels increase while the THC levels decrease.

What Week Do Trichomes Turn Amber?

Expect trichomes to start turning amber about a month after flowering. If you are growing in a controlled environment, you are following a growing schedule that is compatible with most variations of the cannabis plant. 

Trichomes can normally be expected after flowering, maturing, and darkening about one month later. At the beginning of this cycle, look for clear trichomes to appear during the flowering stage, changing to a cloudy and opaque white two weeks later. Under healthy growing conditions, the cloudy trichomes start to darken to an amber color on the tips after another two weeks.

Do All Trichomes Turn Amber?

Not all cannabis strains have trichomes that darken to amber when it is time to harvest. It is important to know what type of cannabis plant you are growing and what you might expect during the maturation process. With the type of trichomes that do not darken to amber, you can’t rely on the trichome colour change to indicate harvest time. 

Younger plants have trichomes that are clear or milky because they are still maturing. The older a marijuana plant is, the more likely that the trichomes are oxidized or darkened to a ruddy amber hue.

Sources:
1. https://jcannabisresearch.biomedcentral.com/articles/10.1186/s42238-021-00062-4
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741114/
3. https://extension.usu.edu/crops/research/ten-frequently-asked-questions-about-growing-cannabis