Soilutions Potting Soil #3 was designed as a 'sponge' to hold water and keep it available when your plants need it without the worry of root rot. A blend of compost, pumice and composted woody materials, this is a succulent and cactus nursery standard. It works well as an amendment to aerate compacted soils or help water retention in sandy soils. When used as runoff points, soil sponges also help reduce water runoff and help filter out pollutants before they enter our waterways.