At the heart of growing your own fruit and vegetables is homemade compost – the result of recycling waste from the garden and kitchen.

But what is compost? It is the result of the natural breakdown of plant material.

This breakdown involves a whole host of bacteria and animals, many microscopic and others, such as worms, large enough to see.

Essentially what happens is that the large chemicals that made up the dead plants are being broken up into smaller chemicals that can be reused by growing plants.

In the wild, composting is essential to ensuring that the soil is fertile enough for plants to continue to grow year after year.

What can you compost? You can compost anything that came from a plant, although there are one or two things to avoid, and some tricks that help make good compost.

First, here are the things to avoid. Do not try to compost raw meat or cooked food as these can attract rats. Do not add very woody material, such as twigs or rose prunings, to your compost without shredding them first.

It is also a good idea to avoid plants that have died because of disease, and persistent weeds such as couch grass and bindweed.

Now here are the tricks – composting works best when you add a mix of things.

Larger things, such as plant stems and big leaves, help provide air spaces for the composting animals to breathe, while smaller things, such as grass clippings, provide lots of food for them and the moisture they need.

If you have only grass clippings, you can use crumpled newspaper and egg boxes to provide the air spaces, so stopping the compost turning smelly and slimy.

This happens when there is not enough air and other types of animals take over the composting process. These animals produce the gases that cause the smell.

It is useful to have two bins or heaps, one for new material and one that is breaking down into compost. This takes around six months if you give everything one good mix (turning) before leaving it alone.

What can I use compost for? Compost in the garden can be used to do exactly the same job it would do in nature, to make sure that the soil can grow plants year after year.

The only difference between what we do in our gardens and what happens naturally is that because we keep our gardens tidy we collect all the material together, rather than leaving it to compost where it falls on the soil.

To use your compost, just spread it around the garden, mixing it into the soil if you want. You can use a mix of soil and compost for sowing seeds and raising pot plants, which is what gardeners used to do before 'composts' came in bags from the garden centre.

Around 6.7billion tonnes of what we throw into our bins each year is waste food, some of which is food we have bought too much of. The waste fruit and veg can be made into compost.