Humus is made up of decayed organic matter such as grasses, leaves and weeds which, because of its richness and ability to contain moisture, is used in a fairly heavy proportion with newly potted plants (see Chapter 7). A humus which has been made with a fairly heavy proportion of peat moss instead of other vegetable material will work more effectively than one made without it. Your garden supply store can provide you with a packaged humus in containers of from one to fifty pounds.