What is it?
Compost is essentially decayed and decomposed organic matter which can be applied to plants in your garden/allotment/patch. Composting is a natural process of recycling organic material into a nutrient rich soil improver. By composting your organic waste you are returning nutrients back into the soil in order for the cycle of life to continue.
Why is it important?
Compost is brilliant at improving the structure and water retention of the soil, it can act as a mulch around plants locking the moisture in the ground and is great at suppressing weeds. It also brings a healthy balance to your existing soil by adding beneficial microbes and fungi which can be essential for proper root and plant development. It is the ultimate recycling machine and the most environmentally friendly way to deal with kitchen and biodegradable waste!
How do we compost?
The site and the bin!
The first thing to consider when composting is what you will compost in. There are an abundance of composting bins which are available to gardeners to buy. You can make your own out of old wood or you can simply for go a composting container or just pile the materials in a heap in your garden. You also have to consider where you will place your compost bin/area. Ideally, the heap should be sited where it won’t be subject to extremes of temperature. You don’t want it baking in the sun one day and then being exposed to cold windy conditions the next. The processes at work in your compost bin i.e. the bacteria and fungi are susceptible to these extremes and would prefer to work in a constant temperature. Most people find it more convenient to site their compost heap in a shady unused area of the garden. My own compost bins are sited at the back of the plot where I would have been unlikely to be able to cultivate anything other than weeds!
Preferably, the compost bin should be open-bottomed, i.e. exposed to the soil underneath. This allows worms and other beneficial insects like woodlice, access to your compost bin where they aid the composting process. However, if your site has hard ground, i.e. concrete, you can get fully enclosed bins. If you go for either an open-ended of full enclosed bin when you have hard ground, then add a layer of compost at the bottom of the bin to kick-start the composting process!
The types of compost bins styles range from plastic round open-bottomed bins, to large square 3-bin composting systems, to hot-composting style rotating bins. Everyone will have a personal preference of what style compost bins they use. For the small garden, a single round compost bin or small heap is normally sufficient. I myself use the large three bin system for my allotment, which my partner and I built ourselves out of old used wooden pallets. If you want to have a look at the different styles of bins and their advantages/disadvantage these websites offer excellent comparisons and help to find the type that would best suit you!
When it comes to what you can and can’t put in your compost bin, there a few hard and fast rules!
- Do not put in meat, bones, fish, fats, dairy and cat and dog poo. Cat and dog poo can harbour dangerous diseases and the meat, bones fish and dairy will stink and attract pests such as rats.
- Do not put in most diseased plant material (those that won’t be destroyed by the composting process). This is sure fire way of spreading the disease further. Diseased plant material should be burnt!
- Do not add anything inorganic such as plastic, metals etc. These are generally not biodegradable and are made up of chemicals you wouldn’t want in your soil. Throw them in a rubbish bin!
- Do not add invasive perennial weeds (such as bind weeds and knotweeds). These weeds and it’s seeds can sometime survive the composting process (if it is not done properly) and then you end up spreading them around when you add it to your soil.
- Do make sure you have a mixture of brown and green material. Your compost heap should contain between 25-30% green material and the rest brown material.
- Green material (high in nitrogen) includes; kitchen vegetable waste, grass clippings/hay, dying (not diseased – see above) plant material, seaweed, annual weeds, manure, coffee grounds.
- Brown material (high in carbon) includes; wood (not coal) ashes, cardboard, straw, leaves, newspaper, sticks and twigs (preferably put through a chipper first) and sawdust.
- Whenever you add a layer of green material, try and add some brown material at the same time.
- Turn the pile often!
- Keep it moist! This is normally only a problem in really dry hot weather but if your compost bins look a little dry then chuck a can full of water on it. The organisms that break down your compost like it humid in there!
We have already said that the organisms within your compost that breakdown the waste into crumbly black soil goodness need a relatively constant temperature and not subject to extremes of temperature and also require moisture. They also require good aeration. Oxygen is part of the processes that break down your waste. This is called aerobic decomposition. If there is no oxygen, you will get anaerobic decomposition which is slower and produces quite a slimy, stinky pile. It will compost down eventually but will take a long time. If you want compost much more quickly it is important to aerate the pile. This mostly means turning the pile with a fork or for those with rotating bins, a quick rotation to jumble the pile up and get oxygen between the materials. With our three bin system we turn the pile by transferring it from the first bin to the second to the third where we then have the finished product ready for use!
This aerobic decomposition also creates heat which helps to speed up the composting process. The micro-organisms create the heat and can heat the pile up quite quickly with temperatures up to 50-70C which is high enough to kill weed seeds and stop them from germinating. This heat does actually deter worms but as the heap cools down worms and other insects involved in decomp will return to finish the job.
The finished product!
When your organic material has undergone the processes illustrated above you will be left with lovely crumbly black soil full of goodness and water retention properties! Use it to mulch your plants and feed them.
So there you have it! Now you know how to make a good compost heap to supply your garden/allotment with nutrient rich compost all year long!