Xanthophylls are yellow pigments naturally present in the leaves of cannabis and other plants. Along with green chlorophyll pigments, xanthophylls help plants absorb light energy and regulate heat. If a cannabis plant is stressed or deficient in key nutrients, chlorophyll can break down, revealing the yellow xanthophylls in a condition known as chlorosis or yellowing leaves.
Xanthophylls belong to a class of carotenoids, the same family of pigments that give carrots and other vegetables their orange hue. In plants, they act as accessory pigments to chlorophyll, broadening the spectrum of light a plant can absorb for photosynthesis. However, xanthophylls become visible in leaves when a plant lacks nutrients, especially nitrogen, causing chlorophyll levels to drop.
Seeing xanthophyll pigments emerge in cannabis leaves alerts growers to a potential problem. It usually indicates the plant is stressed and deficient in nitrogen, sulfur, iron or other key nutrients. Growers can correct yellowing leaves through consistent fertilization, reducing environmental stress, and overall TLC to restore a healthy green color.