Fox Farm Soil & Fertilizer Company makes an organic fertilizer called Tiger Bloom, specifically designed to promote abundant growth during the bloom/bud stage of all plants. It's a liquid fertilizer that can be used in any growing medium, including soil and hydroponic set-ups. Many growers favor Tiger Bloom due to the minimal amount it affects the flavor of the bud, especially if the feeding is ceased 10 to 14 days before harvest. This product is ideal not just for cannabis, but for tomatoes, roses, and nearly every other plant.
Tiger Bloom contains the three main nutrients budding plants need (nitrogen, phosphorous and potassium), along with trace amounts of boron, copper, iron, manganese and zinc.
Calcium nitrate, magnesium nitrate, ammonium nitrate, ammonium phosphate, potassium phosphate potassium nitrate, earthworm castings, kelp, iron EDTA, zinc EDTA, manganese EDTA copper EDTA, chelating agent, disodium ethylenediamine tetra accetate and sodium borate.
Ideally, you want to start feeding your plant Tiger Bloom as soon as it shows signs of flowering. It should receive the mixture a minimum of once per week, but preferably every other watering. For a general feeding, Fox Farm recommends 2 to 3 tsp per gallon of water. For a heavy feeding up the dosage to 4 tsp per gallon of water or 2 tsp per gallon of water with every reservoir change in a hydro set-up. Again, up the dosage to 3 tsp for a heavy feeding. For additional foliar feeding, use ½ tsp per gallon of water and apply once every 2 weeks, but not while in direct light.