Wiggle Worm soil Builder always pure earthworm castings. You need only use a small amount in root zone or around your houseplants, vegetables, flowers, & trees. The miracles of the earthworm are easily seen in the beautiful growth & yields. The nutrients in our castings are always pure & 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 & 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 & last a long time. Omri certified.