I'm not sure where to post this, so the moderators can move it to where ever it needs to go. I am about to buy a new house and I was thinking about adding a compost bin, and then as I looked around the web I then started to think about a worm bed since I fish from time to time. What I have learned and researched, it is pretty easy. My question is I was going to build it in a breeze of the house, attached pic. I was thinking about putting it in the back right on the side of garage not the house. I was going to build a wooden frame, I haven't decided on the size yet. My question is what has been the best to put on the bottom, to keep worms from going underground and escaping and on top from keeping them from crawling out?