We have often discussed the benefits of Vermicast, used inside or out you really can’t go wrong. As a fertilizer it contains all the macro nutrients and micro nutrients (most producers do not test or list these) needed for optimal plant growth. The Humus content of Vermicast is roughly 40% higher than traditional compost, meaning it retains moisture more effectively. When untreated worm castings have a healthy population of beneficial micro organisms. But, how do you tell it all just looks like dirt. Some of the commercial vermicast now available can be a little misleading in its claims of origin. Has it been processed and how was it prepared are two questions you should be looking at when buying worm castings. Some castings have already been made into tea for example, it would be akin to buying used coffee grounds. The nutrients and micro organisms are gone, leached away by the brewing procedure. This product is only suitable for soil conditioning and will not function as a fertilizer or provide the benefits of microbial growth. Another important question is the organic matter source, what base product was the vermicast made from, manure, if so what kind or was it some other waste material like restaurant kitchen scraps. The best way to discover what your castings are really all about is to contact the producer.
Here’s a little test you can use to check out the quality of your castings; place around a table-spoon of castings in a small jar of water, shake it up. The vermicast should separate into layers with castings on the bottom and lighter organic materials rising up. If you end up with only bottom material, your castings have already been made into tea. If you’re lucky enough to have access to a microscope a drop of unprocessed “casting water” will be abundant in microbial life.