How to Make a Compost Bin with Cinder Blocks
Avid gardeners know the value of dark moist compost as they gently work it into the soil around their flowers and vegetables. Not only does compost provide beneficial microorganisms in the form of organic matter to enrich your plants, it lightens heavy soils, allowing them to drain easily. Cinder blocks are a good choice for a compost bin, creating a permanent enclosure with easy access.
- Difficulty:
- Moderately Challenging
Instructions
Things You'll Need
- Cinder brick blocks
- Sand
- Shovel
- Level
- Hammer and chisel
- Finely ground limestone
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1
Choose a flat location for your garden compost bin in an area where water does not pool. Behind a garage is a good choice or beside your garden if you don’t mind a structure there.
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2
Design the size of your compost bin to suit your gardening needs. A small 3-foot by 4-foot bin will hold enough compost to supply a 12-foot square garden. If your garden is larger or your soil is clay-based, consider a larger bin.
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3
Determine the prevailing winds in your region when planning your compost bin. Unlike tumbler compost bins, a cinder block bin is a three-sided stationary structure. The backside should face the direction of the strongest winds to prevent the compost from blowing out.
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4
Use a shovel to dig a flat trench 3-inches deep and as wide as the cinder brick blocks. 8-inch by 8-inch by 16-inch blocks are common but you can use any size you like, just adapt the trench to fit the width. Extend the trench on all three sides until it matches the desired size of your bin.
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5
Spread a 1-inch layer of sand in the trench, leaving an open depth of 2-inches. Starting at the backside lay the cinder blocks end-to-end, tamping them down into the sand until the tops are even. Continue laying the blocks until the first layer is complete.
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6
Start the next layer by offsetting the first cinder block so the ends break in the middle of the block beneath. This will make the second layer a little shorter, by exactly half a cinder block in the open front area. When you reach the back corners, use the hammer and chisel to score and break a cinder block in half to fit. Do this by holding the chisel on the desired breakpoint and tapping it lightly all the way around.
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7
Repeat with a third layer, stepping the blocks back once again. This time the back blocks will fit smoothly as they did in the first layer. Continue the process until your garden compost bin is three or four layers high. The more rows you apply, the higher the backside of the bin will be with sloped sides.
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8
Pour sand carefully into the cinder block holes to steady the bricks and wet the top down carefully with water to compact the sand. If the sand level drops a lot add more and wet it down again.
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1
Tips & Warnings
Spread a fine layer of limestone powder on the ground before adding your compost ingredients and dampen the pile every few days to keep it moist. Use a shovel to turn the pile occasionally.
If you prefer not to cut the cinder blocks, try spacing them a little ways apart, starting with the second layer to create air holes between the bricks. If you choose this method, skip the sand fill and use some short pieces of rebar in the holes to secure the walls.
