With 3% available phosphate and 28% calcium, The Hardener is an excellent choice for building soil phosphate levels and preventing calcium deficiency for long-term plant productivity. The Hardener can be amended into soils prior to planting, used as a top-dressing for established plants and/or mixed into water or compost tea and applied in liquid form. This premium powder grade fertilizer (screened to 140 mesh) is an exceptional nutrient resource for all types of flower plants including bulbs, fruits, shrubs, trees and vegetables.