Help nurture new trees with tree watering bags from Grainger. Slow-release water bags can provide an efficient way to water newly planted trees and shrubs and help promote deep root growth. A 15-gal. bag can soak low-branches bushes and trees for 4-8 hours, while a 20-gal. bag can take 5-9 hours to drain. Zip together two 20-gal. water bags to water larger trees. Find high-quality watering bags at Grainger to help properly water your new trees.