All plants need nutrients from the soil to grow. Composting is a way of hastening the decomposition of plant remains and other once-living materials to make an earthy, dark, crumbly substance that is excellent for adding to houseplants or enriching garden soil. It is a way to recycle your yard and kitchen waste, and is a critical step in reducing the volume of garbage needlessly sent to landfills for disposal.

In the natural world, leaves piled up on forest floors begin to decay and are returned to the soil, where biological agents like worms, insects, fungi, bacteria and other micro-organisms ‘chew up’ the material. Oxidation (exposure to air), reduction and hydrolysis (exposure to water) finish the recycling process by reclaiming the nutrients from the decomposed leaves.

Some scientists have speculated that as early peoples dumped food waste in piles near their camps, the waste rotted and became a terrific habitat for the seeds of any food plants that sprouted there. Perhaps people began to recognise that dump heaps were good places for food crops to grow, so they began putting seeds there intentionally.

You can create your own compost for your house plants or school/community garden by setting up a compost bin.

What to compost

Kitchen waste: Fruit and vegetable peels/rind, tea bags, coffee grounds, eggshells and similar materials are great stuff to compost. They tend to be high in nitrogen and are usually quite soft and moist. As such, kitchen waste needs to be mixed in with drier/bulkier materials to allow complete air penetration.

Grass/lawn clippings: It’s usually easier to leave grass clippings on the lawn, where they will decompose and benefit the soil directly. However, they can be composted too.

Hay: Make sure that any hay you plan to compost is well moistened prior to addition to the pile.

Leaves: Leaves are an excellent compost ingredient.

Manure: Horse, cow, sheep and poultry manure is often available for free from local ranches, farms and stables. Fresh manure can get a compost pile to heat up quickly, and will accelerate the decomposition of woody material, autumn leaves and other ‘browns’.

Straw: Dry straw is a good material for helping keep a compost pile aerated, because it tends to create lots of passageways for air to get into the pile. Be sure to wet the straw, as it is very slow to decompose otherwise.

Weeds and other garden waste: Many types of weeds and old garden plants can be composted. Avoid weeds that have begun to seed, as seeds may survive all but the hottest compost piles.

Wood chips and sawdust: Wood products belong in the ‘browns’ category because they are fairly low in nitrogen. 

What not to compost

Chemically treated wood products: Sawdust from chemically treated wood products can be bad stuff to compost.

Diseased plants: It’s difficult to make sure that every speck of diseased material is fully composted. It’s best not to compost diseased plant material at all, to avoid re-infecting next year’s garden.

Human waste: Human faeces could contain disease organisms that will make people very sick.

Meat, bones and fatty food waste: These materials are very attractive to pests (in an urban setting, this could mean rats…). In addition, fatty food waste can be very slow to break down because the fat excludes the air that composting microbes need to do their work.

Pet waste: Dog and cat faeces may carry diseases that can infect humans. It is best never to use them in compost piles.

Compiled from various sources by Shailendra Yashwant

InfoChange News & Features, March 2006