Garden Professor Jeff Gillman analyzed worm leachate (the liquids the flow our of your worm bin) from a home vemicompost setup. It’s pretty strong stuff! Gillman concludes,
this could be a great liquid fertilizer if it were used properly. I’d recommend diluting it somewhere between 1:1 and 1:5 worm juice : water before applying it, and I’d only apply it once every week or two. If you want to use it, try it on something that you’re not too concerned about first, just to make sure that it doesn’t do anything too terrible (It shouldn’t, but I believe in caution).
To see a full analysis, read his post here.