Liquid vermicompost, or leachate as it is normally called, is a mixture of water run-off and worm urine which is alive with all kinds of microorganisms and has such a high in nutrient that it can be immediately fed to your plants. However, unless carefully strained, it could also contain undigested bits of feedstock that, theoretically, could harbour pathogenic microorganisms. For this reason, some experts advise against using this leachate. Other experts are of a different opinion and suggest that leachate is perfectly safe to use. People who have used leachate have very seldom encountered any problems but it would perhaps be prudent to use it only as a soil drench and not as a foliar feed.
The quality of the leachate will be dependent on how much water is added at regular intervals to the wormery in order to keep the contents at a moisture level of about 70%. Adding water is very much a case of trial and error in the initial stages of worm farming and does require some effort. Leachate should be dark brown in colour and should be diluted to about 1 to 20 units of dechlorinated water. It is advisable to use the leachate immediately and not to bottle it up for a long period; the liquid will become anaerobic and will smell.
Note that leachate is NOT vermicompost tea. Vermicompost tea is brewed and consists of a muslin bag full of vermicompost immersed in a vat of dechlorinated water that is continually agitated by a pumping system. Water circulating through the muslin bag creates a system where the microorganisms are free to percolate into the mixture and nutrients can be extracted from the vermicompost. Vermicompost tea should be used almost immediately and is suitable for soil drench or foliar feed. If a vermicompost tea brewer is purchased from a reputable dealer, the correct ratio of vermicompost to water in the vat will be described; for home-made units it is, once again, a question of trial and error. Beginners are cautioned to use a weak mixture to start with and scale up the concentration once the effect on growing plants has been noticed. Solid vermicompost will normally be a mixture of worm casts and undigested bits of feedstock. Pure vermicast should be 100% worm casts without ANY undigested feedstock. Obtaining vermicast is a very slow process as the worms must not be fed whilst they are re-digesting and eliminating all vestiges of feedstock.
Anyone for vermicompost juice?