Soon to be known as the "World's Greatest Organic Fertilizer!" Wiggle Worm Soil Builder Always PURE Earthworm Casings. You need only use a small amount in root zone or around your houseplants, vegetables, flowers, and trees. The miracles of the earthworm are easily seen in the beautiful growth and yields. The nutrients in our castings are always PURE and provide to be plentiful. Most importantly, these nutrients are perfectly balanced in two forms. One form can be immediately absorbed by the plant as if it were directly injected and the other is able to provide nutrition which slowly feeds the plant for long periods of time. This soil builder is very cost effective because small amounts provide incredible results and last a long time.