The easiest way to think about composting is to pretend you’re cooking a meal for your garden. Let’s pretend you’re making a stew. As with the real thing, for compost you need to prepare your raw ingredients, put them in the correct container and then let them cook and stew.
Before we look at the ingredients and cooking instructions, some basic principles need to be explained:
Types of Compost
Composting is the facilitated decompostition of organic matter for ease of absorption by plant life. In other words, you are supporting the natural process of the decomposition of your garden waste. The end result of this process is that the nutrients stored in the garden waste are broken down by bacteria so that they can be absorbed by new plants.
There are two main types of bacteria and these form the two methods of composting. Aerobic composting depends primarily on the work of aerobic bacteria. Anaerobic composting requires only anaerobic bacteria.
Aerobic simply means that the bacteria depend on oxygen for their survival. These little organisms are rapid breeders and rapid eaters of the organic matter. They break down your garden waste quickly and efficiently.
This is the recommended composting option, however, it is also the more labour-intensive as the compost requires regular turning. This is the method that we will follow in these instructions.
Anaerobic bacteria on the other hand, do not require oxygen. They break down the garden waste very slowly. Anaerobic or ‘cold’ composting takes a much longer time. It is the easier option: involving little work, simply piling the organic waste in a big heap and leaving it for many months.
The Cooking Pot
Composting works best in a loose structure or ‘pot’. For example, an ideal structure is made of four old pallets tied together at the corners. Whatever you build, make sure that there is plenty of room for air to access the compost. A sealed wooden or brick structure will not work well. The cooking pot should be placed on loose ground in a shaded area.
For small gardens, a single ‘pot’ will suffice. When you need to turn the compost, simply remove the walls of your pot, allow the compost to fall out and then rebuild the whole pile in an adjacent space.
For bigger gardens, a permanent system of three ‘pots’ works well. These should be lined up side by side. Pot A can be turned into Pot B, Pot B into C, and so forth in a cyclical pattern.
Sticks and small branches
Wet greens (fresh cuttings/leaves, fruit and veg peels, teabags)Dry browns (dry cuttings/leaves, shredded newspaper and shredded cardboard)
Manure (optional, although critical for rapid composting)
Do not add: fruit and veg cuttings with seeds, meat scraps, anything rotten or mouldy.
• Within your loose structure (the pot) loosen the ground soil with a garden fork or spade.
• Place the sticks and small branches at the bottom. This allows air pockets to form once you start layering in the other ingredients on top.
• Place a layer of wet greens about 2-3cm thick. If you don’t have enough, ask your neighbours to keep their scraps for you, or approach your local fruit and vegetable shop for their old stock.
• Place a roughly equal layer of dry browns directly on top of the wet greens.
• Place a roughly equal layer of manure directly on top of the dry browns. Manure, or soiled straw, can easily be found at any stable.
• Note – at each stage, add enough water so that each layer appears damp.
• Repeat this process with another series of layers, filling the cooking pot as high as possible, or until all your ingredients are finished.
• Finally, cover the pot with a lid. Another pallet, an old piece of carpet, or some shade cloth are good options. This keeps the compost dark – encouraging the activity of bacteria and animals such as earthworms which are crucial to the composting process. The lid also limits evaporation.
Leave your pot to stand for two weeks. In the meantime, you may want to start a second compost pile, following instructions from the top. After the two week ‘cooking’ period, turn the compost into a new pot. Cover and leave to stand.
Transferring the compost is absolutely critical for the rapid breakdown of the organic matter as it exposes the pile to more oxygen.
After another two weeks (four weeks in total) transfer the compost into a third pot. Cover and leave to stand for another two weeks. After six weeks in total, your compost should be ready for application! This process will take longer than six weeks in winter, without turning, and if there is no manure.
You will know the compost is ready when your kitchen and garden scraps have broken down completely, the layers can no longer be seen and you have cooked a healthy looking, soft-to-the-touch, moist pile of garden goodness! Yum!