Cold composting

Cold Composting

In every garden and neighbourhood there is an abundance of organic matter around such as deciduous leaves, strips of bark, prunings and accumulated lawn clippings. There are a few ways of recycling this valuable resource for your garden.

One of the easiest ideas is to make a cold compost pile where all this material is heaped up and is gradually allowed to gradually break down such that it will be ready for use in spring. Burying your kitchen scraps in the pile will periodically stimulate the microbes that are responsible for the composting process. As for things like fallen leaves and bark, these materials are often reasonably low in nutrients and because of this, will take longer to compost. But they do add valuable carbon into the heap, which helps to maintain a good balance.

The easiest way to compost such material is to place it in a heap where material can be added as it comes to hand. Various commercially available plastic bins (commonly sold by local councils) can be used, or simply construct your own heap using steel star pickets (poles) and chicken wire to contain the material. The pile can be any size depending on how much space you have and how much material you will be adding.

There are a few materials you can’t use with this method. Woody stems that are any thicker than your little finger will take too long to break down, unless you can chop them up into very small pieces in a mulching machine or with secateurs. Most weeds are also unsuitable for this method as they will tend to sprout again and simply start growing in your compost heap. It is safe, however, to include young, tender weed seedlings up to 10 to 15 cm tall that have not flowered and produced seed. If you are in any doubt it is best to leave it out. Many local councils now have green waste collection services or recycling sites at garbage tips where these unsuitable materials can be left for professional compost manufacturers who can recycle this material safely.

Step 1 Place or construct your compost pile in a a reasonably flat, sheltered corner of the garden. For cold composting a key feature of the pile is that you must purchase or construct a unit that has a flap or gap at the bottom that will allow you to remove the finished compost at regular intervals. The whole idea is that every few weeks there will be a harvest of a small amount of compost that will allow you to keep adding more material to the top of the heap each week or so.

Step 2 Add any garden and lawn clippings. Smaller woody stems should be chopped up as fine as is practical to enable faster composting. If you are adding a lot of material at once it is a good idea to also place it in layers a few cm thick, alternating with similar layers of any kind of animal manure that is available. The manure will add extra nutrients to speed up the breakdown process and add fertility to the end product. It is also possible to use kitchen scraps in this layer as well provided they can be buried under a layer of leaves or lawn clippings to prevent fruit fly and other insects from getting to them. If you are really keen urine is a wonderful liquid source of nitrogen to speed the composting process!

Step 3 Every few weeks you should be able to remove a layer of dark, rich compost from the bottom of the pile. This will create a gap at the top of the pile to allow you to keep topping up the heap. When the compost has a crumbly soil-like consistence it is ready to use by digging it into your garden soil in preparation for new plantings. It can also be used as a mulch on established plants.