The full flavour of a cannabis plant is only achieved when it is fully mature. Just as harvesting too early results in a loss of effects, harvesting too late results in a reduction of THC and thus a loss of effects. The aim is to harvest the plant at the peak of its psychoactive potency. Understanding what happens to the cannabis plant in the final weeks before ripening and harvesting makes it easier for you to achieve the ideal and desired effect and, in this context, to find the right harvest time.

Signals that indicate maturity:

  • the fine fruit filaments in the calyxes are increasingly turning brownish. About 70% of the filaments are brownish when the plant is ripe. This is because fresh resin and cannabinoids are clear in acid form. They turn brown when they are converted into their active forms and the resins polymerise. However, the colouration of the hairs alone cannot always be considered a reliable sign because this is highly dependent on the type of plant and the variety.
  • the plant produces almost no new white threads any more
  • the calyxes are very swollen and full of resin
  • the buds are compact, hard, dense and covered with a resin layer
  • of great importance is the colouration of the trichomes (resin glands)

when should I harvest, cannabis

The trichomes

Correct harvest time for cannabis plants

The colour of the trichomes indicates the degree of maturation and is the best way to tell when a plant is ready to be harvested. The trichomes have their cycle like everything else in the cannabis plant. They are born as small spots on the leaves and calyxes and slowly and gradually develop into stick shapes that have a ball at the top. THC, CBN, CBC and the other valuable cannabinoids are produced in these resin glands.

Trichomes Cannabis

  • At first, the trichomes (with the "ball" on them) are transparent, clear and translucent. This can be seen very well with a grow microscope. As long as the trichomes are still clear and transparent, the plant is not yet ready for harvest.

Trichomes Cannabis

  • Later on and when the flowers are in their full maturity, the trichomes are milky, white and cloudy. The terpenes (aromatic molecules) are at their optimum point and produce an intense aroma. The cannabis plant can now be enjoyed. However, some growers prefer to leave the plant for a few more days until some (more) of the milky trichomes have turned amber, brownish.

Trichomes Cannabis

  • When 30% - 50% of the trichomes are amber, harvesting should be done at the latest.

If you harvest when a large part of the trichomes are already amber, you will get a grass that is very heavy and oppressive after drying. I prefer to harvest when 30% of the trichomes are amber and the rest milky white.

Trichomes of sativa plants are usually longer and thinner than trichomes of indica plants. Resin glands in indoor cultivation are generally larger than those of outdoor plants. With many cannabis strains, especially indicas, it is possible to harvest part of the flowers and leave the remaining part to ripen further. However, there are some strains, and especially sativas, that don't like this very much and then don't finish the remaining flowers properly.

Ultimately, it is not possible to say across the board when the right harvest time is, as this is also a question of personal taste. Some prefer an earlier harvest time when most of the hairs are still fertile (i.e. white) and at the peak of their resin production. Others prefer to harvest later because they want a strong and resinous weed that has more of an effect on the body and has relaxing effects.

The best way to observe and control the trichomes is with a small microscope, in the growshop area special Microscopes have been developed for this purpose.

THC is probably produced more at night. Therefore, the plants contain a little more THC in the morning than in the evening. Do not fertilise the last 2 weeks before harvest. This way, fertiliser residues are still used up in the plant.

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