Trichomes
The resin glands on the flower where cannabinoids and terpenes are made and stored.
Trichomes are outgrowths of the plant's surface. On cannabis flowers the glandular kind matter most: each one is a tiny factory with a head of secretory cells and a cavity above them where the resin collects.
Three types are described by shape — bulbous, sessile and stalked. The stalked ones, raised above the surface on a multicellular stalk, hold the highest cannabinoid content, and research has shown they develop from sessile-like precursors rather than being a separate lineage from the start.
Growers read trichomes by eye to judge harvest time: clear heads turn milky, then amber as the acids inside degrade. It is an imprecise method, but it is the one available without a laboratory.
Sources
- Livingston, S. J., et al. (2020). Cannabis glandular trichomes alter morphology and metabolite content during flower maturation. The Plant Journal, 101(1), 37–56. DOI