if the leaves are turning yellow beginning at the tips and gradually working itself to the whole leaf, chances are the plant is probably becoming Nitrogen(N) Defficient. All you do is buy a Nitrogen Supplement such as, Fish Emulsion, Worm Poop, Bat Poop, or Blood Meal. when feeding this nute to your plant only use 1/4 of the recommended dosage on the instructions! also.. how much are you watering? if its several times a day or even once everyday then the yellow leaves may be a sign that you are rotting away your plants root system. hope that helps