Humus is organic matter that has decomposed to its furthest point, retaining and storing nutrients, which can be released to plants when the humus is added to soil, according to University of California at Davis Extension. Humus is created slowly by the microbial activity that breaks down plant tissue. This process is sped up in home compost bins, resulting in the dark crumbly nutrient-rich humus used as a garden soil conditioner. Humus is easily created by following a few easy composting principles.
Collect nitrogen-rich green materials and carbon-rich brown materials to use in layers in the compost bin. "Greens" include yard trimmings, grass clippings, kitchen peelings and chicken manure. "Browns" are dry leaves and weeds, shredded newspaper and household paper, sawdust, and straw.
Place a 4-inch layer of brown materials at the bottom of the compost bin. Material that is chopped into small pieces decomposes faster.
Add a 6-inch layer of grass clippings, kitchen waste and other green materials to the bin.
Spread an inch-deep layer of garden dirt over the first two layers. The microorganisms in the soil act as an inoculant to start the decomposition process, according to University of Illinois Extension.
Repeat this layering process until the bin is full, adding water as needed to keep the pile moist. The compost pile will soon heat up and begin to decay.
Turn the pile after several weeks by using a garden fork to move materials at the outside of the pile to the interior of the pile. Compost is ready to use as humus in three to six months. When the original materials are indistinguishable and the soil is loose and crumbly, it is ready, according to University of Illinois Extension.