Expert Gardener Citrus Plant Food, 6-4-6 Fertilizer 4 lb., is made of immediate and slow-release fertilizer granules to feed your plants immediately and to keep on feeding throughout the growing season for up to 3 months. Expert Gardener Citrus Plant Food also contains a customized mix of micronutrients including Magnesium, Sulfur, Iron, Manganese and Zinc needed by plants to thrive. The macro and micronutrients in Expert Gardener Citrus Plant Food is specially formulated to provide the right nutrients required for lush trees and delicious fruits.