If yields have been slipping for several seasons on the same piece of ground, the problem is usually soil rather than seed. Compost is the cheapest way to start reversing that, because the raw material is already on the farm and being thrown away.
What goes in
A compost heap wants a mixture of green, wet material and brown, dry material.
- Green: weeds pulled before they seed, kitchen peelings, vegetable trimmings, fresh grass, animal manure.
- Brown: dry grass, maize stover, banana leaves, husks, ash in small amounts.
Keep out diseased plant material, weeds already carrying seed, plastic, glass, batteries and anything treated with chemicals. A heap rarely gets hot enough on a small farm to kill everything, so what goes in tends to come out again.
Building the heap
Choose a shaded spot near the garden, since you will carry the finished compost by hand. Loosen the ground first so the heap drains and soil organisms can move up into it.
Build in layers, roughly two parts brown to one part green, each layer about a hand deep. Sprinkle water on each layer as you go and add a thin scatter of soil or old compost every few layers to introduce the organisms that do the work. Aim for a heap around a metre wide and a metre high: much smaller and it dries out, much larger and it will not get air to the middle.
Cover it with banana leaves, grass or an old sack. The cover keeps moisture in and heavy rain out.
Water and air
The heap should feel like a wrung-out cloth: damp, not dripping. Too dry and it stalls, too wet and it turns sour and starts to smell.
Turn it every two to three weeks, moving the outside material into the middle. Turning is what keeps it aerobic and is the difference between compost in three months and a slumped, sour pile still recognisable a year later.
Knowing when it is ready
Finished compost is dark, crumbly, and smells of soil rather than of rot. The original materials should no longer be identifiable. On a small farm with regular turning, expect roughly two to four months depending on how fine the material was chopped and how warm and wet the weather is.
Using it
Work compost into the soil before planting rather than scattering it on the surface, where it dries out and does little. Applied in the planting hole or along the planting line it goes further than broadcasting, which matters when you never have as much as the garden could use.
Compost is a soil builder, not an instant fertiliser. It improves structure, water holding and the soil is ability to release nutrients, and it works cumulatively over seasons. Do not expect one application to transform an exhausted field.
A note on fresh manure
Fresh animal manure applied straight to a growing crop can scorch roots and will bring weed seed with it. Composting it first solves both problems and makes it easier to handle.
Related reading: Farming Guides and Crops.