Home composting bin design assistance
Hi, I've spent a decent amount of time looking online for plans for a 3 bin composter (using some reclaimed deck cedar) but cannot seem to get a clear answer about a few things: 1. Do I need to put a hinged cover over all three bins? Or perhaps just bin #1, the starter bin? A cover would serve to keep critters out and also allow you to control how much rain water enters each bin. Perhaps having individual covers over each bin is the best solution? 2. I'd like to elevate my composter off the ground using some concrete retaining wall blocks at each corner - approx a 6 to 8" lift. I would then need to put a bottom in each of the bins. Is this a good or bad idea to separate the compost materials from the ground? If it's ok, could I use wire cloth for the bottom? Or would there be a concern about the bins drying out from the bottom? I could potentially have enough of the reclaimed cedar where i could make the bottom out of this with some air gaps (1/2" or so) between the boards. I look forward to your feedback! Thanks, Bob
Hennepin County Minnesota
Quickly to answer your two questions:
1). You need individual covers on all three bins. The overall idea of a three bin system, in contrast to a single bin or pile,is that you are able to do in three stages what otherwise would occur in a single stage. A three stage system enables you to speed up the whole composting process. A cover on all three bins will assist in heat retention which will accelerate decomposition.
2). Put your bins directly on the ground. Composting is dependent upon decomposition by bacteria and fungi. If you put a floor on your three bins, this means that you will be dependent upon bacteria and fungi coming in with the materials that you are composting. By putting bins directly on the ground, bacteria and fungi have another entry point - the ground! - by which to enter the bins. This again will speed up the process.
The following two sites will give you further information: