With the right conditions (air and moisture), organic waste such as food and plant materials is decomposed by bacteria, fungi, worms, and organisms. Decayed organic matter is humus. Yard waste such as grass and flower clippings can also be composted.

Composting comes in two kinds: bin/pile composting and worm composting (vermiculture).

Bin/pile composting is easier for many households because one does not have to be too careful with what to put into it. Here is what you need:

• Get an old bin or box (1 cubic yard), or you can buy one from the shop. Ensure that you punch holes around it to help with aeration.
• Prepare your organic waste matter. Make sure you cut them into pieces (about 1inch in size). Do not throw in big chunks of the waste. Make sure you separate the organic waste into brown and green parts. Brown parts include waste like wood chips, saw-dust, yard waste shreds, straw and hay, dry leaves, and shredded paper. Green parts include grass trimmings, fruit and veggie scraps, green leaves, and livestock manure.
• Put the waste in the box in layers, 50% green, 50% brown.
• Mix and add some water every 7 days.

In a couple of weeks, the compost will be ready. It will look dark-brown and smell just like soil.

There are other larger composting units used in schools and some restaurants. These have larger cylindrical chambers of about 8-10 feet in length. Waste items are usually layered in the chamber, with dry leaves on food waste layers. The content of the cylinders is turned regularly for aeration to speed up the composting. It takes about 2-3 weeks for the composting to complete.

Commercial composting units are a lot more sophisticated, as they are tested for color, pH, odor, moisture, and other related characteristics that appeal to compost buyers.