Worm Kaster's worm castings are unlike chemical fertilizers that can burn tender roots. Worm castings are an organic fertilizer that are safe to use at any concentration. Organic gardeners rely on this method of fertilizing because its organic nutrients balance the soil's PH and help to retain the soil's moisture. Worm Castings also provide you with an excellent organic insect and disease repellent.
 
Plants love organic fertilizer made from worm castings! Along with many other trace elements and micro-nutrients, castings have 5 to 11 times more nitrogen, potassium, calcium, phosphorus, potash, and magnesium than topsoil.
 
The minerals are water-soluble and time-released. So, they are easily available to the plant when the plant needs them, both immediately and long-term.

The following links provide more information about worm castings.