Plants need a lot of chemicals to grow well. However, if you' don't have high light and CO2 levels, the chemicals may not be needed at all.
Plants need light, CO2, N,P,K, Iron, and trace elements.
N= Nitrogen; often available in the forms of ammonia and nitrate in the tank
P= Phosphorous; Enemas are a cheap source of P
K= Potassium; Morton's NoSalt Salt Substitute or Potassium Nitrate (Green Light Stump Remover)
Iron can be added in liquid form, or as a dry chemical
Trace elements are available in both liquid and powder form
CO2 can be made from scratch at home for a couple dollars a month.