Humboldt Nutrients' Grow (NPK Ratio 2-1-6) 1 quart hydroponic plant nutrient solution is one part of a 3-part nutrient system that includes Humboldt Grow, Micro, and Bloom. Functioning as a vegetative and root stimulator, it can be used during all stages of the plant growth cycle. Grow is derived from ammonium nitrate, magnesium nitrate, potassium nitrate, and other minerals and nutrients. Grow even contains proprietary chelating agents, making uptake more efficient and insuring none of the nutrients fall out of solution, causing lockout. Designed to promote stellar growth and lush vegetation, use Humboldt Nutrients' Grow with soil or hydroponic systems and watch your garden grow.