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| part of my compost corner. The plastic sacks contain various rotted materials, wood ash, etc. |
WHAT IS COMPOST?
First we need to be clear about what we mean by compost as there are two distinct types. The bags of growing medium you buy from garden centres are normally known as compost and are available for a confusing number of applications. Peat-free, ericacious, John Innes.... I won’t go on and anyway, that’s not the sort of compost I want to talk about.
The other type is the kind of stuff you can make at home in a compost bin or simply an open heap. It consists mainly of rotted vegetable matter and is very beneficial to the soil as it improves structure and aids water and nutrient retention. To me it is one of the most important aspects of gardening: getting the soil right. There’s an old saying that you only get out of the soil what you put into it so it follows that if you feed the soil it will feed you!
WHAT CAN YOU COMPOST?
Basically you can compost anything that's been alive at some point, although some things rot down much faster than others and so give quicker results. The secret of good compost is what goes into the mix and experienced composters refer to two basic ingredients, brown and green matter. These are hard woody material such as shredded twigs and straw and soft green plant tissue like grass clippings. They are also sometimes known as carbon and nitrogen materials. Ideally you should aim for a mix of both and if you can’t get hold of woody material you can use torn up cardboard and shredded paper.
I’m lucky in that I live in a rural area close to the sea so I can get hold of horse and sheep manure and seaweed to add to my heap. This is mixed with cardboard, tea bags, grass clippings, shredded twigs, kitchen and garden waste, the contents of the Hoover bag and anything else that will rot down. One thing I don’t add is meat or any meat product. Not because I’m vegetarian but because it is liable to attract vermin. It is also not a good idea to add any plant matter that might be diseased as this may be passed on to new crops.
It’s worth remembering too that potato peelings and tomato seeds will often not be killed by the composting process and you can get lots of fresh growth sprouting from your neatly raked seedbed. Also if you are going to put perennial weeds on your heap it's a good idea to steep them in water for a few weeks to partly rot down or the seeds may not be killed. The water can be used as a liquid feed so nothing gets wasted.
A lot of male gardeners swear that adding their own urine to the heap has beneficial effects. I do it myself, but not when the neighbours are looking. I have a bucket in the shed. It certainly contains nitrogen and probably helps to speed up the breaking-down process.
Compost is really the ultimate in re-cycling. You take plants from the soil and the bits you don’t eat go back into the soil. You also stop a lot of stuff going into landfill sites or being burned, both of which can be damaging to the environment. It becomes a closed loop like most natural systems.
MAKING A HEAP
The simplest method is just to pile stuff up in a spare corner of the garden/plot. One thing to remember is that to get best results a heap needs some air circulation and sunlight to help it warm up. If you mix your materials you should automatically get air spaces and these can be increased by turning the heap regularly with a garden fork. Another cheap and easy way to make a heap is to get hold of four used wooden pallets and fasten them upright in a square. If you wish to spend a bit of money you could buy a couple of the plastic bins or ‘daleks’ as they are affectionately known. These can sometimes be got from local councils at a discounted rate. There are compost tumblers available which produce well-rotted material in a much shorter time if you are desperate to get going. Traditional methods take time and you should always be planning for the year after next!
LEAFMOULD
This is another form of compost or soil additive and is easily made. All you need to do is knock four posts into the ground in a square, wrap some wire netting around them and rake up the leaves from your lawn. If you don’t have a lawn just gather them from the surrounding street and lanes. (you might get some funny looks) Eventually these will rot down by the action of fungi and bacteria and give you a usable product in twelve months but if left for another year will be much finer and easier to use. For this reason I have two leafmould frames on the go at any one time. When sieved small and mixed with sharp sand and a little soil it makes excellent seed compost.
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| finely sieved leafmould |
DEVELOP A MULCH MENTALITY.....
Mulching involves putting layers of rotted material on the surface and letting worms do the job of incorporating it into the soil. While it is actually on the surface it serves two purposes: it suppresses weed growth and helps conserve moisture. Fruit bushes and trees benefit from an annual mulch of compost or manure.
WHEN TO ADD COMPOST
It doesn’t really matter. Some people apply it in autumn, some in spring. Some dig it into the soil, some leave it on the top. As it doesn’t contain a great deal in the way of nutrients they can’t get leached out. The purpose of it is to improve the structure of the soil. Obviously you wouldn’t dump it on top of your newly-emerged seedlings so it usually gets applied when there is nothing much growing.
There is a belief among some organic gardeners that you can't add too much compost. Research shows that you certainly can and an over application can result in excessive acidity in the soil and high potash concentrations which upset the uptake of other nutrients. Traditionally manure/compost application went hand-in-hand with crop rotation and liming so that a balance was maintained. Don't be put off by this. It will take a few years of very heavy application of compost to make much of a difference but as gardening is a long-term business you should at least be aware of it. Or you could always sprinkle a little lime regularly as you build up your heap.
