TCS GrowStar™ professional fertilizers are blended with the highest quality raw materials on the market, filtered three times before bagging to provide limited dust and formulated with the most innovative technologies to assure outstanding results. This fertilizer contains XCU® slow-release fertilizer technology. XCU® slow-release fertilizer is unique to the market and provides gradual, steady nutritional uptake for up to 10 weeks of plant response. The 6% iron ensures lush, green foliage.