Pure Life's premium organic earthworm castings work with your soil to promote plant growth and root structure. Pure Life's Worm Castings contain essential plant nutrients and beneficial micro-organisms which increase moisture retention and optimizes growth. The castings can be used both indoor or outdoor for seed germination, seedling propagation, and on existing plants. We recommend creating a mixture that consists of 80%-85% of existing soil and 15%-20% of premium organic castings. Purelife also includes directions on how to use the castings with varying beds, baskets, and lawns on the back of the bag.