Essential Rules of Compost Making
Essential Rules of Compost Making
When making compost, use a mixture of tough and sappy ingredients to ensure active composting and a good end product. Add as much as possible at once. It is important to provide sufficient moisture but do not let the heap become.
Build air into the heap, cover and enclose it to keep rain out and prevent moisture and heat loss. Never use pesticides on a compost heap. Experiment until you find a method that suits you, and do not worry if the end product is not perfect: it may still be usable.
Hot or cold composting?
The quick hot heap
The quickest method of making compost is in a hot heap — that is, one where the ingredients heat up noticeably. This is done by filling a compost container in one batch using the right mixture of materials, preferably chopped or shredded if tough. A hot heap kills many weeds, pests and diseases.
The main disadvantage of a hot heap is that few people have sufficient material to achieve it. Another problem is that it may lose some of its value; nitrogen is given off as ammonia from a very hot heap, hence the smell.
The cool bit-by-bit heap
Most gardeners add ingredients to the heap as they become available. It may or may not heat up and is called a cool heap. It can make excellent compost but can take a year or so. As the ingredients are unlikely to heat through, any diseases and weeds present may not be killed
Pros and cons of hot and cold composting
- Quick-action, making compost in as little as 6-8 weeks
- Most weed seeds and roots, as well as diseases, are killed
- Requires a lot of material at one time
- High temperatures can reduce fertility of end product by driving off ammonia
- Can be built as materials become available
- May be more fertile as nutrients are retained
- May take a year or more to compost
- Weeds and diseases may not be killed
Speeding up the composting process
One of the most common complaints that is made about making compost is that it takes such a long time to achieve a useful end product. However, whether you are making a cool heap or a hot one, there are ways of speeding up the process.
Filling the container
Although it may not be possible to gather sufficient material initially to fill a whole compost box, always make an effort to add as much material as you can at once. For example, mow the lawn, weed the border and collect a sack of manure or vegetable waste from the local market within the same few days. Never add individual items.
Chopping and shredding
Chopping or shredding tough compost material, such as old brassica stems, can increase the speed of decomposition dramatically. This is because chopping a stem into many pieces increases its total surface area, giving the composting micro-organisms a much greater area to work on, so the speed of breakdown is increased.
A compost shredder can be very useful here, but it is not worth buying one unless you have a lot of woody material to dispose of. Chopping with a sharp spade or shears and bashing tough stems with a hammer will do the job.
Turning the heap
A compost heap may sometimes heat up initially then slow down. This is because it has run out of air in the middle, or because it is too wet or dry. The answer here is to turn the heap. Remove the material from the container, then rebuild the heap. Tease out the contents to incorporate more air; add water or sappy ingredients if the mixture looks dry; add dry, tough material if it seems wet. The material that was at the outer edges of the heap should be moved into the centre. A hot heap can be turned every few weeks until it stops heating.
It is also worth turning a piecemeal heap that has not heated up, either after each new addition of material or with the last addition.
A simple way of turning a compost heap on a regular basis is to use a compost tumbler. This can produce compost in as little as three weeks.