I'm not familiar with the Earthtainer. That website doesn't really explain the construction of it in enough detail for me to understand how it might be converted for vermicomposting. What's the barrier between the top and bottom made out of? Does it come apart?

Are you familiar with vermicomposting and have you done it before?

alynoa: Please keep in mind that liquid collecting at the bottom of a worm bin is not "tea". It's leachate.

IMO, almost any container could be used for vermicomposting, with adjustments. Is your Earthtainer like the cross-section drawing on http://earthtainer.tomatofest.com/ Do you have any compost. I suggest you use compost to start rather than using soil. Depending how many worms you are going to start with, you could even use both levels at the same time. Like having 2 bins in one. What size is your Earthtainer? No need to wash the inside unless you have used chemicals in it before.

If you decide to use the bottom part for worms also, I suggest you keep an eye on moisture from the food scraps. Wicking (upwards) is a much slower process than leaching (is that a word?) and we don't want to drown them. How big is the hole on the side? It could be a plus if somehow you could cover it with a fine screen. But actually worms could go through weed cloth if they could find even a tiny opening. But if everything is peachy in the bin, they'll stay put.