Johnson's recommends using ferti-lome Start-N-Grow Premium Plant Food when you're planting trees, shrubs, vines, and perennials. Simply add Start-N-Grow into the planting hole to maintain your landscape plants throughout the season. This slow-release fertilizer can also be used as a maintenance fertilizer by applying to established plants every 3-4 months during the growing season. Can be used on indoor plants, too! Provides gradual, consistent nutrient release when plants need it. 20 pound bag.