Properly managed, a compost bin creates the ideal environment to transform yard waste and other plant material into humus, a rich, dark brown, crumbly soil amendment. Appropriate amounts of air and moisture along with a proper temperature range will encourage microbes to break down plant tissue at a rapid rate. But if organic materials of varying sizes are added to the compost pile, smaller pieces may be finished composting while large pieces, like corn cobs or wood chips, remain uncomposted. Screening will separate larger, incompletely decomposed materials from finished compost. Keeping partially composted material out of your garden prevents it from possibly retarding germination and seedling growth, or from competing with plants for the nitrogen in the soil, according to the University of Illinois Extension.
Cut mesh to fit the frame. Nail the mesh in place on the backside of the frame, bending the nails over to hold the mesh in place. Pound down any nail ends that may have poked through the frame.
Hold the mesh screen over the wheelbarrow. Place a scoop or two of compost on the mesh and shake the frame from side to side to sift the compost.
Dump out the debris that does not fit through the screen. Create a pile of "overs" for your next batch of compost since these partially composted materials contain microbes that will help jump start the composting process as well as bulk, which improves aeration.
Continue sifting through the compost a few scoops at a time until you have sifted the entire bin contents. Use the sifted compost for mulch or for amending garden soil.