Cold Composting is one of the easiest ways to recycle and reuse in the garden. All organic waste, which means any food and kitchen scraps including egg shells and even cardboard and paper, and also all garden waste, basically anything that would be put in a green waste bin to dispose of can instead be turned into compost to condition soil and return nutrients to the garden.
Cold composting is one of the most practical ways to compost as it requires little maintenance and can be added to continuously as needed. Around autumn there is an abundance of organic matter around such as deciduous leaves, strips of bark and accumulated lawn clippings. There are a few ways of recycling this valuable organic resource for your garden.
Perhaps the simplest option is to use this material as mulch on your garden beds. A layer up to 10cm thick will provide a moisture saving blanket that will also reduce water losses as well as gradually compost down to improve the soil around your plants.
How to build a cold compost heap
Another easy idea is to make a cold compost pile where all this material is heaped up and allowed to gradually break down such that it will be ready for use in spring.
There are many different ways to build a compost heap, depending on the requirements of the garden and the amount of waste to be composted.
The best way to build your own cold compost heap is to create a compost bay, or multiple bays if there are large amounts of waste to deal with, this way the compost can be rotated through different bays as it goes through different stages of breaking down. The simplest and best design is simply a three sided bay, which can be built on site from scrap wood such as wooden pallets or any other easily obtained wooden frames. The fourth side should be left open for easy access to your compost heap so that it can be turned or mixed occasionally. A lid or even a hessian sack over the compost can be added to keep away pests and contain the compost heap.
There are a few other simple designs that are just as effective and simple to assemble.
Bays can be built from chicken wire or similar materials, or “high rise” compost heaps can be created within a wire cylinder stood upright on one end.
Alternately a wire cylinder or barrel laid on its side is a great way to contain compost, and very easy to rotate and mix by simply rolling or cranking with a simple handle.
There are also commercial bins available in many styles similar to the designs listed above, however it is an easy and satisfying project for the home gardener to build your own DIY style compost heap, and certainly does not require expensive equipment to start out.
An excellent variation on this idea is to create a raised garden bed with a pit dug in the center, the compost heap can then be layered into this hole. It can be gradually added to and will provide a continuous supply of nutrients to surrounding plants. An even simpler variation on this idea is to simply bury compost in holes around the garden and cover with soil and mulch, although if this method is chosen it is very wise to mark the sites of compost in the garden, and avoid burying close to the base of plants and trees as it will leech nutrients from surrounding soil if it is not finished compost.
There is a simple rule of ratios to ensure your compost heap breaks down efficiently and avoid unpleasant smells. The pile should be built up in layers of “dry” or “brown” waste such as dead leaves and pruning off cuts, alternating with “wet” or “green” waste such as kitchen scraps. The dry waste is high in carbon and fibrous matter, and the wet waste is high in nitrogen creating a balanced environment for decomposition in which beneficial microorganisms can thrive. Burying your kitchen scraps in the pile will periodically stimulate the microbes that are responsible for the composting process. You will also find earthworms thrive in cold compost, they help to break down organic matter and will also benefit your soil greatly when returned to the garden.
- A good ratio to aim for is a dry to wet ratio of 2:1; 2 parts or about 20cm deep of dry waste to 1 part or roughly 10cm of wet waste. This will keep the compost heap in balance and is a good rule of thumb to follow when building a cold compost heap. This can be constantly added to, and when the lower layers are finished and ready to use the top layer can then be removed and used to begin the next compost heap.
- The pile will break down into a rich sweet smelling compost which is ready to apply to potted plants or straight back into your garden beds. This can take from 6 months to a year with the cold composting method.
Cold composting is the perfect way to begin composting for anyone with a little space and limited time, and is the easiest way to start out.
The only drawback compared to other methods is that it takes quite a bit longer than hot composting, and as it does not reach high temperatures and “cook” it is possible for weeds, pests and diseases to survive the process.
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