Composter Designs

Compost bins come in all shapes and sizes. Big, small, short, tall – it’s easy to make good compost with them all. Compost bins can be made out of just a few recycled scrap materials, or they can be custom manufactured and loaded with bells and whistles. Compost bins are like cars – the one you choose can be as stylish or as practical as you want it to be.

The first type of compost bin is the homemade compost bin. This is the equivalent of a boxcar derby car: it doesn’t have to be perfect, and you can take pride in the “character” of the unit. A compost bin can be made from mesh wire, scrap wood, bricks, cinderblocks, or a combination of those building materials. Scrap yards and construction sites are good sources for this building material – just be sure to talk with the site manager before loading up on materials. What looks like useful junk to you isn’t always free for the taking, and stealing is a bad way to start out.

Round bins deliver the most interior space and use the least material. For their volume, they are lighter weight than rectangular or square compost bins. This type of bin also has the least surface area for its size, which means it offers the most possible self-insulation and conserves heat better than blocky designs. On the other hand, rectangular compost bins make the most out of the available space. The thickness of their walls is the only wasted area, and they deliver high capacity for a small ground footprint. If there’s a shortage of space in your yard, rectangular compost bins are your best choice.

The walls of your composter can be as sturdy as you want them to be. It doesn’t hurt to over-engineer the structure; a composter built to withstand normal stress can fail when it’s full and you bump into it, or when a tree falls against it. Half-inch nails or screws offer good holding power and they’re inexpensive. Plastic twist ties or zip ties are also good for holding together mesh screens, and metal twists are even stronger.

Wire composters

Photo found on Flickr.com courtesy of Carolyn

A wire composter is simply to build and is a basic way to protect your food scraps from wild animals. It can be made from chicken coop wire, hardware cloth, or even chain link fence. Wire can be used to make a round or rectangular compost bin. For a round bin, simply roll the wire into a cylinder, and then tie the ends together. For a rectangular wire compost bin, start by placing 4 (or more) poles into the ground. Then, wrap the wire around those stakes and tie it together. The height and diameter of the compost bin are determined by the length and width of the material you work with. For example, a section of wire that’s 3 feet wide and 10 feet long will become a 3 foot tall circular composter with a diameter of about 3.18 feet. A sheet of plywood across the top makes a decent roof to keep out rain. There are also plenty of commercially manufactured wire composters that you don’t have to build yourself.

Wood framed composters

Photo found on Flickr.com courtesy of net_efekt

If you know how to work a drill, it’s also easy to make a wood framed compost bin. You’ll need a few boards to get started – they don’t all have to be the same length, and scrap wood is perfect. Start by building a wood frame with four boards arranged to form a square or rectangle. Then, nail or screw the boards together to form a rigid frame. Repeat the process to form a matching side. Then, stand the frames up on their side and connect them with cross beams. Support beams may be needed on the sides. To keep animals out, the compost bin can be wrapped in wire, clad in plywood sheets, or even faced with boards. Once again, you can purchase a professionally manufactured wood composter if you don’t want to build it.

Brick or Cinderblock compost bins

Wood frames can rot over time, but there are more durable options made from brick or cinder blocks. To assemble one of these bins, start by building the sides just like stacking a wall. The bin you build will not be very easy to move, so you should assemble it in place. The bricks you use should be tight fitting to keep out drafts. For an even stronger structure, you can mortar the bricks together or run lengths of steel rebar through the centerline of the cinderblocks. Most brick and cinderblock compost bins are made with only three sides. This makes it easier to aerate the piles and shovel out finished compost. A wire gate or sheet of plywood works well on the front of the composter, and plywood can be used to create a lid.

Plastic bins

Photo found on Flickr.com courtesy of CleanAirGardening.

If you have nightmares about power tools or if you prefer neat, cleanly organized compost, plastic bins are also available. These prefab compost bins are lightweight and durable. The most basic type of plastic bin is a garbage bin with holes punched in it for drainage and aeration. It’s ugly, but it works, and it might be a good choice if you want to go as cheap as possible.

Commercial plastic bins come in all colors, shapes, and sizes. If you live in a cool area, a dark colored bin is recommended. Dark bins absorb heat from the sun and help keep active bacteria at the proper temperature. Plastic compost bins often have vent holes and lids built-in, as well as sift trays or access panels at the bottom for removing finished material. Whatever features you want, there’s a good chance that you can find a matching bin.

Tumbling bins

Photo found on Flickr.com courtesy of CleanAirGardening.

Turning compost by hand can be a time consuming and stressful process. Tumbling composters offer an alternative method of aerating compost. Instead of using a pitchfork or an aerating tool, you can spin a tumbling composter and let gravity do the work. As the contents of the bin fall they run into the axle in the middle of the composter. This axle breaks apart clumps of compost and keeps the bacteria from turning sour.

There are also tumbling composters with hand cranks and electric motors. These composters often have internal machinery that further aerates the compost. Rotating screws are common, as are fins and grinding gears. These complex composters can accelerate the composting process, but they also have more parts that can break, wear out, or malfunction. With compost, the KISS principle is your friend.

Multi-stage bins

Wire, wood framed, plastic, and tumbling bins are also available with more than one compartment for compost. Multiple compartments allow compost to be divided based on its age. This batch composting method will get the fastest results for each set of compost, and the other compartments offer a place to put new compost without resetting the clock. As each compartment fills up, there should be another compartment that’s ready to empty out and use in the garden.

Another way to “multi-stage” is to use more than one bin. Throw your fresh materials into one bin until it is almost full. Then start adding material to your second compost bin, while continuing to mix and aerate the first bin as it breaks down into finished compost. When one of the bins is finished, empty out the fresh compost and start the process all over again.