Gibberellins are diterpenoid plant hormones; more than a hundred are known, a few of which (such as GA1, GA3, GA4) are biologically active. They promote stem and internode elongation, break seed dormancy by triggering enzymes that mobilise seed reserves, and influence flowering and sex expression.
In practice
Gibberellin activity sits behind much of the early-flower stretch and shade-avoidance elongation. Many plant growth regulators sold to keep plants short work by blocking gibberellin synthesis. These are best avoided on a consumable crop.
In cannabis sex expression, gibberellic acid (GA3) applied to female plants can induce male flowers. Historically it was one of the methods for producing pollen from females, though silver compounds (silver thiosulfate, silver nitrate), which block ethylene action, are far more reliable for feminised-seed work.
Gibberellin seed soaks are used on dormant seed of some crops. Fresh, healthy cannabis seed rarely needs them.
Don't confuse with
- Auxin: drives elongation and rooting through a different pathway.
- Ethylene: in cannabis, promotes female flowering and ripening.
- Stretch: the growth response; gibberellin is one of its drivers.
The length of stem between two adjacent nodes; short internodes mean compact plants and tight bud stacking, long ones mean stretch.The stretch is the rapid increase in height in the first two to three weeks after switching to flower, when many cultivars grow 1.5 to 3 times taller.A male flower that carries stamens (anthers on filaments) and no functional pistil; in cannabis, five drooping sepals around five pollen-shedding anthers.STS (silver thiosulfate) is a silver compound sprayed on female cannabis to block ethylene action and induce fertile male flowers, the standard method for making feminised seed.Nitrate (NO3-) is the main form of nitrogen in hydroponic and soilless feeds; its uptake tends to push root-zone pH upward.A gaseous plant hormone that regulates ripening, senescence, stress responses and, in cannabis, female flower expression; blocking it makes females produce pollen.The dry, single-seeded fruit of cannabis that growers call a seed; a hard shell (pericarp plus seed coat) encloses one embryo and does not split open.A class of plant hormones, chiefly indole-3-acetic acid (IAA), that drives cell elongation, apical dominance, bending toward light and root formation.In cannabis growing, a plant (usually female) that develops both pistillate and staminate flowers or anthers; botanists call it intersex or monoecious expression.
