Rich, black compost conditions soil and adds nutrients to boost plant growth. A 55-gallon drum barrel can be converted in several ways to make a compost bin for turning food scraps and plant material into compost. Options include standing barrels in which you stir the compost, or more complex styles with frames and rods for tumbling the material. Regardless of type, you must drill 1/2-inch holes throughout the barrel so air can reach the composting material.
Layered Vertical Bin
Layers of fencing with different-sized openings allow the composting material to work its way to the bottom of the barrel as the material decomposes so you can access the finished compost while adding new material at the top. Visually divide the barrel into thirds. Push two to three 1/2-inch rods or conduits through the barrel at each of the one-third points to create shelves. Cover the bottom shelf with a circular piece of fencing or hardware cloth that has small holes. Place a circle of agricultural fencing or chain-link fencing over the top shelf. Cut out a roughly 12-inch square from the bottom one-third of the barrel sides. Reattach the square with a hinge at its top and latch lock at its bottom so you can access the compost when finished.
Rolling Vertical Bin
This compost barrel stands upright but can be laid on its side and rolled around to mix the composting material. This design requires a barrel with a screw-on lid or tight straps to hold the lid in place. Cut out a square from the lid and reattach it with a hinge and lock so you can access the barrel easily when adding new composting materials. Drill small 1/2-inch-diameter holes all over half of the barrel so when it is laid on its side, the half that faces up is covered with aeration holes, with no holes on the half that touches the ground. This way, you can rock the barrel to mix composting materials without the liquids or fine compost falling out through the holes. When the compost is finished after a few months, access the finished material through the small door or unscrew the lid and dump the contents.
This bin starts out much the same as the basic standing compost bin, but it rests on its side on a V-shaped frame. The square access door must be cut and reattached on the side of the bin, not at the top or bottom. Build a compost frame for the barrel from two-by-four lumber. The frame looks similar to a saw horse with a wide, flat surface on top of angled legs at each end. Add diagonal braces between the legs for additional support. Install rigid roller casters or old steel roller skate wheels facing up on the frame top. This requires a total of eight wheels installed in pairs, two pairs on each side of the top. Space the wheels so they line up with the horizontal ridged bands around the barrel. Set the barrel on the wheels, fitting the ridged bands between the wheels. Spin the barrel once every few days -- the wheels will let the barrel turn.
In this version, the basic standing compost bin is given a rod through the center for turning, much as food turns on a spit. Holes are drilled through the barrel so a 1-1/2-inch pipe or rod can fit through the center; each end of the pipe or rod fits into notches in posts on either side of the barrel. The posts must be tall enough to suspend the barrel off the ground so it can spin freely. This design keeps the compost barrel in a dedicated space and the free-turning style eliminates the hassle of rolling it on the ground. Every few days, simply give the barrel a spin on the rod to turn the composting materials and redistribute heat.