GardenLine | Yard & Garden | Common Sense Gardening and Compost

Composting is a method of recycling house and garden waste into a soil "amendment" which will improve both the structure and fertility of the soil. The compost will also increase the soil's water holding and nutrient holding capacity. During the composting process microorganisms naturally present in the soil break down the vegetable waste materials into an inorganic form that can be used by plants.

What to Compost Almost any vegetation may be used for compost: carrot tops and peelings, outside lettuce and cabbage leaves, potato peelings, banana skins, tea bags, egg shells, and coffee grinds. Grass clippings, leaves, and general garden refuse (dead top growth of annual flowers and vegetables as well as herbaceous perennials) are also compostable.

What Not to Compost:

Avoid using meat and dairy products; they are much more likely to attract neighborhood dogs and cats as well as mice abd rats. Also avoid incorporating weeds which have formed seed heads. Some weed seeds may survive the composting process and germinate a year later in your garden. Any diseased plant material (such as peas with powdery mildew, roses with blackspot, or apples with fireblight) should be burned, garbaged, or taken to the local dump. The fungal and bacterial organisms in the diseased materials may survive the composting process.

Do not use fecal material from dogs, cats, or pigs as compost. These may contain eggs of ascarids (round worms) or other parasites which can infect humans.

Where to Compost

Compost piles should be accessible! . Ideally, locate your garden close to the house and the compost pile adjacent to the garden. The location for the compost pile should be well drained and in semi-shade. Compost located on waterlogged sites will produce foul-smelling gases.

Container Options

Compost can be made in a simple pile (or "heap"), a homemade container, or a commercial composter. Simply piling refuse on a heap is probably the least asethetically pleasing of the 3 options. The sides of the head will tend to dry out, thus slowing down decomposition; and the compost will probably need turning several times before it is ready to use.

A container 1 m3 in size will satisfy the compost requirements of the average urban gardener. Although commercial compost bins are available, they are expensive. You can construct a container from logs, exterior grade plywood, railroad ties or heavy-duty wire netting lined with polyethylene sheeting (to prevent the outside of the pile from drying out.).

How to Compost

Place the materials to be composed on the pile (or in the container) in even layers, limiting a layer of any one particular material to 5 cm. Every 15 to 20 cm add a thin layer (1 to 2 cm) of garden soil. The soil will provide the microorganisms needed for decomposition of the vegetation. If reasonably fertile garden soil is unavailable or you wish the process to be speeded up, a commercially prepared compost activator may be used; follow the instructions on the label.

Along with the layer of soil, a handful of a high-nitrogen fertilizer (such as 34-0-0) may be sprinkled evenly over the pile. The nitrogen will be used as a source of energy for the microorganisms which decompose the vegetation.

Be sure that the top of the pile is either flat or slightly concave (bowl-shaped). This will ensure that any rain water or applied irrigation will not run off; the compost will thus remain evenly moist.

If the compost pile is located adjacent to the garden area it can be easily watered every time the garden is watered. This will produce a fairly even rate of decomposition during the growing season. As the pile builds up the bottom layers will begin to decompose. Decomposition is most active during the warm weather of summer when bacteria are most active. Little or no decomposition will occur during Saskatchewan winters.

Late summer or early fall is a good time to begin a compost pile. Leaves, garden and border refuse, and kitchen waste from canning and freezing are readily available and cooler temperatures make the compost construction more comfortable. Continue to add to the pile through the winter, spring, and following summer. If the compost bin is located adjacent to the garden, remove or rake aside the undecomposed top layer, and incorporate the finished compost into your vegetable and flower beds. It should be dark brown and look like soil and not be offensive to feel or smell (most gardeners get to like the touch and smell of compost!).

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Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.