In another file we talk about building your own compost bin. Here we chat about what to look for if you have decided you want to buy your compost bin. To buy a bin that’s best for you, consider design, size, material and the cost. For details about composting in general and building a compost bin see the file Composting.
Ventilation - Whether you have a passive or active bin, look for openings along the sides and top for proper air transfer. Air access from the bottom as well as sides of the pile is important for both passive and active systems. A wooden pallet or two under the commercial bin, if it has air holes on the bottom, will help. The bin should be covered, either with a lid, tarp or plastic sheet, since some moisture helps but heavy rain or snow retards decomposition.
Box style commercial compost bins are easy to fill but don’t facilitate active turning of the pile. Some are made of wire and others of waste lumber. Good for a passive pile. The cost of a box bin can range from $30 to over $200. You can find some high-priced box bins made of molded resin or plastic materials with air vents, lids, and sometimes special liners to improve efficiency.
Barrel style commercial compost bins are popular because they are not terribly expensive, look neat and tidy in the back yard, and have easy access, good protection from the rain, and some are easy to roll around helping to get more oxygen into the pile. The top of the line versions sit up on a frame and have gears attached to a handle that allows you to turn the pile daily with little effort.
Size of Commercial Compost Bins
Research has proven that the most efficient compost pile is one that is 4 feet by 4 feet by 4 feet. That size pile produces the highest internal temperatures which serve to accelerate the decomposition process. Few commercial compost bins are that size. A large commercial bin will be 3 x 3 x 3 feet which gives you a volume of about 22 bushels of uncomposted organic material; still enough to get some good heat going inside the pile.
Most commercial bins hold less than that ideal 22 bushels of organic material. Even though a smaller volume can still heat up, and if turned regularly, can even approach the high temperatures needed to kill pathogens and weed seeds, it’s best to look at commercial bins as containers for simple piles that will decompose passively. Any commercial bin holding less than 12 bushels of organic material should be viewed as a passive composter and not appropriate for an active composting system. Overall height of the access hole affects how hard it is to load and lift damp material.
Design of Commercial Compost Bins
Active Bin – To produce compost relatively quickly and efficiently, you will need a bin designed for easy periodic turning of the pile of waste to get more oxygen in and to speed decomposition. Also look for a bin that offers easy access for filling via a removable front panel or cover of some kind.
Passive bin – If you want to recycle yard waste by storing it neatly until it decomposes, and you are not pressed for time, a simple box or cage with a cover will do the job.