Things You'll Need
Composting, or mixing together various organic materials to hasten decomposition, works faster with smaller pieces of material. You can easily throw kitchen waste into a blender or food processor to shred, but yard waste such as small twigs, garden debris and fallen leaves need something bigger. Instead of purchasing a dedicated power shredder that sees use only a few days a year, many gardeners devise an easy, do-it-yourself method.
Gather the material to be shredded into one area.
Lay a large plastic tarp on the ground and stake the four corners down to keep the wind from blowing it away.
Pile approximately a bushel of debris in the middle of the tarp and scatter it around.
Detach the bag from a lawnmower if it has one and close the port. Move the wheels to the highest level.
Run the lawnmower back and forth across the material several times. Look at the material and see which pieces are being shredded and which ones are not. If a significant amount is not shredded, then adjust the wheels downward a notch and try it again.
Continue to inspect the material and adjust the wheels until you find the best setting for cutting the debris. Keep the material towards the center of the tarp so that it doesn't blow off the edges.
Rake the shredded material away and place new material down. If any material such as pine cones proves resistant to the shredding, remove it from the pile. Continue until all the material is shredded.
Shredding leaves and woody twigs blunts the mower blade edges. Sharpen the blade before cutting grass.
A mulching mower shreds more finely, but it is not necessary for most compost uses.
Wear safety glasses to protect your eyes from any flying debris while shredding material with a mower.