Roots Organics Phos Bat Guano is an excellent source of phosphorus and calcium. Carefully processed and sifted to make it easy to work with, Roots Organics Phos Bat Guano encourages vigorous flowering and fruiting. All of the Roots Organics guanos have been carefully sourced for quality and harvested with bat-friendly methods so you and your garden get performance with principles. Roots Organics 100% naturally occurring bat guano. No additives. No filler.