Africa Energy Indaba

Composting

Recycling of food & garden waste for re-use

Composting on your building grounds is a great way to recycle some of the food and garden waste for re-use in your surrounding garden areas, planter boxes or pot plants. Practically anything that has lived at some stage can go into compost. This includes lawn clippings, garden weeds, and kitchen scraps. These are all rich in nitrogen and carbon which can be broken down relatively quickly.

The key to making good compost is getting the balance right between the carbon content and the nitrogen content. At least two-thirds of the mix should consist of material high in carbon like dry leaves, bark, sawdust, shredded paper, wood ash, egg cartons (pulp) and dry grass. Materials high in nitrogen include weeds, pruning, cut flowers, vegetable scraps, fruit peelings, pet manure and freshly cut lawn. Oxygen exposure is critical to the process. The final product is moist and has a fibrous texture. It’s dark in colour and smells earthy – ready to enrich your buildings garden soil for planting.

Useful Information

Housing Containers

There are various size composting containers available.

Water Requirements

Add water to moisten but not too much

Zero-Compacting Recommended

Don’t compact the mix because you want oxygen to be available to the bacteria and fungi which break down the material into humus.

Heating Response

To enable heat to build up, aim to achieve a mass of about 1 cubic metre at the end of the process.

Storing & Best Practice

Cover the heap to keep off the flies and position the composting unit in an area not frequented by building users.

Estimated Timeframe

Depending on the size, composting can take between six to twelve months if just left alone. Breaking material down into smaller pieces and regular turning with a garden fork will reduce the process down to three to four weeks.

Materials That Should Not Be Added To The Mix

The following items can’t be composted: large tree branches, bones, fish, meat, fats and oils, dairy products, plants with bulbs, plastic, metals and glass.

Spoiler title

Building owners with limited space may opt for the fermentation process which uses beneficial microbes to ferment organic waste, rather than compost it. It is a centuries -old Japanese method called Bokashi. The end result is a fermented (or pickled) mass of waste that can go straight into the soil. There’s no need to compost the material, and it doesn’t smell. The bucket is small enough to be placed under a sink indoors.

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