Question from Tom:
Do you know of anyone that has collected the run off water from
several bins and processed the water for a spray. Does the water
contain the “leeched” nutrients and minerals that could be used, for
example, as a additive to house plants.
What you’ve described is actually what a LOT of people would refer to as “worm tea” (“vermicompost tea” etc) – largely thanks to misleading info provided by worm bin manufacturers. The best vermicompost tea is of course actually made using finished (nicely stabilized) vermicompost.
Can leachate be used as a liquid fertilizer? Absolutely – but it’s important to realize that not all these drainage liquids are created equal!
The “quality” (for plant fertilizing purposes) will depend on the age of the bin, how well it’s been maintained, and what materials have been added to it. For example, a fairly new system that’s been overfed and just generally poorly maintained, will likely have a leachate that contains high concentrations of anaerobic metabolites – some of which may be phytotoxic (harmful to plants). On the flip side, if you are collecting liquid from mature bins (with lots of finished vermicompost in them) that have been properly maintained, the drainage liquid will likely be quite similar to actual vermicompost tea.
If I was going to use leachate from a newer system I’d likely dilute it with rain water (or aged tap water), and perhaps even aerate it before putting it to use. I’d also likely use it for outdoor gardens rather than smaller container plants.
Just my 2 cents! Hope this helps.