No matter what you do, you’ll need two. When the first tumbler is “full” (and by full I mean it’s half full of composting items + half full of air) you’ll need somewhere else to put your scraps. When the first square is “full” (actually full to the top with compost scraps) you’ll need somewhere else to put your scraps.
Tumblers are my favorite if you’re going to buy something. They are easier to turn/stir/mix than the black or green square ones. Tumblers off the ground work better than the ones on rollers, the rollers get jammed up pretty good! They’re fairly easy to make at home, instead of spending beau coup dinero! Uh, I think that’s French (not sure about French spelling words) and Spanish for “A lot of money.”
Black or green squares don’t add up to much. The optimal size for getting your compost heated up properly is 3’x3’x3′. You know, 36 inches in every direction. The square bins are typically 28″, which is why they make them in “sunlight-absorbing” colors, to try and use the sun to help heat your compost. They are nice and neat, therefore marketable.
Do-It-Yourself home bins come in many forms. Wire cylinders, big piles, 4′ square pallets (my personal fave), screens, chicken wire, two by fours, hardware cloth, the list is endless. Pallets are by far the cheapest, they’re FREE! We like to twist supermarket bags into “rope” to tie them together. 🙂 Cosmo’s Foods used to sell their empty 40-50 gallon pickling drums for $7…