Mag-Pro 2-15-4 is a supplement high in phosphorus, magnesium and sulfur. This unique plant supplement can be used with any complete nutrition formula as a blossom booster to help initiate flowering and develop large, vibrant, fragrant flowers. The nutrients in Mag-Pro are immediately available, giving your plant the ability to access the nutrients they need at the critical times of flower formation to ensure massive growth and enhanced aromas. Growers using reverse osmosis, rain or de-ionized water will benefit from the addition of Mag-Pro throughout their plants growth cycle. Mag-Pro is THE blossom booster for growers looking to maximize the beauty and value of their crop. Available in 8oz, 1 quart, 1 gallon and 5 gallon sizes.