Mills Nutrients are the least expensive premier nutrient line for high quality plants. Mills Nutrient line is simple with only 5 bottles. Use the Mills nutrient line of Basis A, Basis B, Start-R, Ultimate PK, and C4. Mills Plant Nutrient C4 is responsible for: Quicker more abundant fruit set Promotion of plant growth and vitality Increased oil and sugar production Development of denser, harder and heavier fruit and flowers Usage Use at 4 ml to 8 ml per 1 gallon starting week 2 of Bloom thru week 6. C4 will make your bloom EXPLODE! Compatible with all growing medium and watering methods.