Humboldt's Own G-10(Gravitation-10) flowering supplement began as a product named Gravity. Humboldt saw an opportunity to ramp up Gravity'ss effectiveness and thus G-10 was born. G-10 still has the kelp extract of the original Gravity but at a whole new level. Add G-10 on the third week of your plant'ss flowering cycle and until the end of the flowering cycle. Want even better results? Use G-10 with Sonic Bloom and Killer Tea. Humboldt's Own G-10'shas been through extensive testing and reformulation to be a replacement for Gravity. It does not contain any PGRs.