you can use Organic Gem a product that is all organic and will not burn the roots if you follow the directions on the bottle. Its pretty cheap 1 qt will make 32 gallons of fert. It increases sugars in the plant, which in turn makes the plants healthier and less susceptible to disease and insect damage. It has all kinds of good things like vitamins, amino acids and enzymes and growth hormones which make the herbs taste better. If you know what i mean.:stoned: