This special 5-10-5 mix of slow-release fertilizers is easy to apply, and promotes healthier growth and more bountiful blooms. Breck’s Dutch bulb experts have created a special blend of slow-release fertilizers to help bulbs and perennials develop healthier roots, grow bigger and stronger, and bloom longer and brighter. Experts strongly recommend adding these select nutrients. Each 13 oz package feeds 40 square feet.