Expert Gardener Tomato & Vegetable Garden Plant Food Fertilizer 12-10-5. contains a slow release nitrogen formula that feeds for up to 3 months. In addition to customized macronutrient levels of Nitrogen, Phosphorous, and Potassium targeting all types of Tomatoes and Vegetables this fertilizer also contains a customized mix of micronutrients such as Calcium, Magnesium, Sulfur, Iron, Manganese and Zinc. The macro and micronutrients in Expert Gardener Tomato & Vegetable Garden Plant Food 4lb, is specially formulated to provide the right nutrients required for delicious top-quality tomatoes and vegetables.