Purp is slang for purple flower, or a cultivar known for turning purple. The colour comes from anthocyanins, water-soluble pigments that some genotypes produce in leaves, bracts and sugar leaves.
In practice
Genetics decide whether a plant can turn purple. Cool night temperatures in late flower, often a drop to about 15-18 °C (59-64 °F) or below, increase anthocyanin expression in plants that carry the trait. A plant without the genetics stays green however cold it gets.
Purple stems and leaves in veg can also mean other things, including phosphorus or cold stress. See purple stems and leaves.
Don't confuse with
- Purple as a strain family: many names contain "purple"; the name does not guarantee the colour.
- Deficiency purpling: dull purple petioles with other symptoms, not glossy coloured bracts.
Myth check
"Purple weed is stronger" or "cold nights boost terps and resin". GenetixBay position: colour from cold is real; claims of more terpenes, flavour or resin are a myth unless peer-reviewed data shows otherwise. Bag appeal is not quality, though the founder admits he is "a sucker for any red strain". See Mythbusters.
The genotype is the set of alleles a plant actually carries, either at one locus or across its whole genome, as opposed to the traits you can see.In cannabis, the small leaf-like sheath (perigonal bract) that wraps each female flower's ovary and carries the densest capitate-stalked trichomes.A small leaf growing from within the flower cluster, often coated in trichomes, which is trimmed off and commonly kept for processing.A nutrient deficiency is a shortage of an essential element in the plant tissue, causing characteristic symptoms; the cause is often pH or uptake rather than an empty feed.The stalk that attaches a leaf to the stem at a node; in cannabis it carries all the leaflets of a palmate leaf.Cold nights are deliberately low night temperatures in late flower; they can bring out purple colour in cultivars that carry it, but don't raise terpenes or resin.Terpenes are volatile hydrocarbon compounds built from five-carbon isoprene units; in cannabis they are made in the trichome heads and are a major part of aroma and flavour.Bag appeal is how good flower looks in the bag or jar, frost, colour, density and trim, which sells cannabis but does not measure its quality.A water-soluble flavonoid pigment stored in cell vacuoles that colours leaves, stems and flowers red, purple or blue, set by genetics and enhanced by cool temperatures.
