Bigger is better; composting, my way

Any pile of organic matter can rot down eventually, but the time taken and the value of the resulting material will vary enormously depending on exactly what we do. We can make better compost but like baking a better cake it takes a little more care. Mine is so good you could almost eat it!

Unfortunately the original Indore method came from India; in their hot climate decomposition proceeds very quickly. Thus they ensured their waste material was built up in layers interleaved with alternate ones of soil, and manure. The soil was there to absorb nutrients -and to prevent the reaction proceeding too quickly and actually combusting. The manure added to the heating to some extent but it was the background temperature that made the composting proceed quickly, even though the heaps were made in the shade.

In damp cold blighty the same method can work to an extent but is slower and cooler, especially as most gardeners are usually lacking manure. So the bulk of the material doesn't heat up much and the composting kills few weed seeds or pathogens. Thus the ill adaptation of the Indore method to a British climate causes many people to believe compost making to be smelly and slow. However the original technique can easily be improved in four ways to work more efficiently; firstly, the thick layers of soil are reduced, secondly, the construction of the heap must take at least two stages, thirdly, the heap needs insulating to retain heat and fourthly, bigger heaps can be made.

The soil layers are needed to absorb nutrients and as inoculants of micro-organisms, save for the topmost layer they need not be more than a thin sprinkling on every layer of wastes, especially if sievings from previous heaps are added. Soil usually contains lime or chalk which sweetens the heap by absorbing ammonia and neutralising acids. As we add less soil we should add sprinklings of lime, chalk or calcified seaweed instead (unless we want a lime free compost for acid loving plants).

As a compost heap heats up it partly sterilises the wastes converting them into fertility and creates an army of micro-organisms that are different to those formed in a cold heap. The heating up is caused by the decay of vegetation but more so by the breeding of the micro-organisms feeding on the decay and on each other. This all uses a lot of oxygen so getting more air into a heap is necessary to improve the composting. However too much air and it takes away the heat both chilling and drying out a heap.

Some have tried to improve composting by building on top of air-pipes, gratings or faggots "to ensure airflow through the pile". It seems unlikely that this on it's own enables any quantity of air to penetrate far into the pile of decomposing vegetable waste above. However I find plunging a crowbar vertically through the heap to make chimneys helps on it's own or in conjunction. Much more importantly you can incorporate air when constructing the heap. Thus the initial period of filling the heap with layers is seen as part one or 'collection'. Once enough are accumulated then part two or 'composting' proper can begin. This is done by digging all the ingredients out onto a plastic sheet and by mixing these ingredients up in as finely divided a state as possible before re-packing them in the container. Then by making another turning after a fortnight or so you incorporate even more air while re-mixing the ingredients again. Twice or thrice turning makes a much better compost much more quickly than just building up a heap. There are special rotary composters that mix the material as often as you like, in theory these should work. However these are more useful in warmer climates as here they do not heat up very effectively and most can only cope with small amounts at a time. I've found they work better if insulated by covering them in bubble wrap.

Equally important is insulating the top of the compost heap to keep the heat in. I usually make the topmost layer a thick one of soil then I cover it with layers of carpet, cardboard, plastic sheets and bags stuffed with straw or newspaper balls. I make a crowbar hole but stuff it with loose straw to prevent it venting too much heat away. I leave the crowbar set deep in so I can withdraw it to see the progress. The initial cooking usually takes about a week or so. During this time the bar gets too hot to hold! Once the heat fades it's time to remake the heap. The centre of the heap becomes the new sides and the old sides are made the new centre. This second turning allows correction to be made if the heap is too wet or dry. Wet heaps need more straw or shredded newspaper adding. Dry heaps often have Firefang attacks of white fungus which wastes nutrients; drench the materials with water and urine before re-packing. After a heap has been given it's final turning and the heat has gone I remove the container or supporting walls to reuse them but leave the top covered to throw off rain. The heap matures for a few months and then I sieve it. I can sieve it because it has dried out, if it is wet and heavy it needs to mature longer, or have a better roof. Only sieved compost is used in the garden, the sievings out are added to inoculate the next heap after stones and plastic etc. are removed.

I use sieved compost as a sowing and potting compost, a top dressing and I incorporate it in the soil when planting hungry feeders or perennials. I rarely need add anything to my sieved compost and it provides for most plants as well as any bought in compost. However for the marrow family I do find mixing in some fresh grass clippings really gets them going. True it does have some weed seeds in it but if necessary they are treated in pots by covering the compost with a layer of sterile material such as gravel or cocoa shell. I have said nothing about what I put in my compost heaps. Well obviously all the usual stuff goes in but also old cotton undies, woolly socks and pullovers, old pillows, mattresses, road victims (of the small furry kind) and everything else that has ever lived. Almost anything that will ever rot does go in and I allow my chickens to pick it over all first. Pre-processing by fowls removes a lot of seeds and converts high grade food stuffs into eggs. Meanwhile the chickens turn over the material, knock it about and spread droppings on it, this all helps it breakdown once in the heap. Other than the chicken dung I use no manures but I add as much urine as I have saved as it is very rich in minerals and makes a heap really cook. I find a good substitute for strawy manure in the heap is stinging nettles and I allow several clumps to prosper so I can crop them whenever I make compost, they will take two or three pullings a year. I also grow clumps of comfrey for much the same purpose, the leaves do not heat well themselves but ooze nutrients especially potassium. They are thus placed above drier tougher materials which stops them panning. To catch such juices I always start the heap with a thick layer of dry straw, newspaper and cardboard.

My containers have varied over the years. I've made compost in real bins, improper bins and very improper bins, chicken netting, pallets (my favourite), plastic sacks, dustbins, pinball machines (sic), car tyres, tractor tyres, baths and dead freezers. I find the container makes little difference on it's own, other than the insulation and shelter provided. And equally, providing care is taken over the ingredients, the mixing, the aeration, the moisture, the insulation, the turning and the maturing there is one important thing that has become very apparent! Big heaps work much much better than small heaps! Small composting units can be helped to work better by re-mixing the ingredients more times and adding more insulation. (A dead refrigerator or freezer is a good container for this method.) And fortunately small heaps do not have very much material to turn over as big heaps. However the product of a big heap always seems better and I'm sure this is due to the greater temperatures reached throughout the whole mass. I find the optimum is about the size of four or five pallets tied at the corners.

The problem is that most people do not produce enough material to fill such a decent sized container in one go. The materials are accumulated in dribs and drabs and eventually when a bin is filled the lower half has already undergone an anaerobic degradation. The answer is to get more composting material. It is after all next year's fertility and food. The most useful job in the garden is searching out and bringing in such fertility. Find a few barrow loads of other people's wastes and hey presto your heap and your garden flourish. More compost cures the vast majority of plant and soil problems. Bigger heaps make more, and better compost, more quickly. So go ye forth and ransack the streets, the shops and your neighbours for all their kitchen and garden wastes. It is even worth while tidying and weeding an old lady's garden for her just to get your hands on all that lovely vegetable matter. And you may get tea and biscuits thrown in.