Green Thumb® GT56607 Lawn Food with Surfcote, 27-0-3, 15000 SqFt CoverageMake your lawns green, lush and thick by feeding them Green Thumb Lawn Food. Easy to use. No waiting necessary, lawn is safe to walk on immediately after application. Includes 2% iron for deep greening and 50% controlled release nitrogen. Continuously feeds for up to 16 weeks. Easy to use Improves rooting & color Promotes thick, lush green lawns 2% iron for deep greening 50% controlled release nitrogen Continuously feeds for up to 16 weeks.