Making Your Own Organic Compost Heap

compost heap filled with material

An environmentally friendly way to improve soil condition is by recycling garden and kitchen waste into organic garden compost.

This is one of the most economical ways of getting the best from your garden. Once added to the soil this natural humus provides a host of benefits, such as improved soil structure, increased moisture retention and replenishes the important bacteria and microbes needed for good plant growth. It also prevents existing nutrients from being washed out of the soil and adds additional nutrients, in a slow controlled manner. These organic materials work like glue in the soil, joining small particles together and also prevents them from being packed too tightly.

Before the introduction of commercial peat (and now peat free) composts, home-made garden compost and leaf mould were the raw materials used by most head gardeners and nursery growers.

What Can You Put in a Compost Heap?

Any organic matter that has lived can be added to the heap. It is best to use a variety of ingredients and mix them together well. An even mix of fine woody/twiggy waste with green leafy waste is best (moist and dry
materials). Too much of one type of ingredient, such as massed grass clippings, can easily result in a pile of green smelly slime. So stockpile ingredients until you have enough different materials to mix them evenly in the heap.

You can add any organic waste from the garden such as dying foliage, spent crops, leaves, clippings, cuttings, non-perennial weeds, straw, finely shredded prunings, hedge clippings and grass cuttings. Also kitchen waste, vegetable peelings, shredded paper and shredded cardboard can be added. It is best not to add cooked foods, fat, bones or meats as these degrade very slowly and will attract flies and rodents.

Woody prunings need to be cut as fine as possible, ideally using a shredder. Take care which weeds you put in the compost, roots and seeds from perennial and invasive weeds are best avoided, for example do not add bindweed. Also, thick shiny leaves, such as holly, can take a very long time to rot down.

What Type of Container is Best for a Compost Heap?

In theory the bigger the heap the better, as the compost generates its own heat during decomposition, so the larger the pile the more heat and bacteria is created. A simple pile on the ground will do the trick but obviously this can take-up much needed space in the garden, does not retain heat well, and can look untidy.

Therefore some kind of enclosure/container is best. A box made from recycled wood such a old pallets and lined with chicken wire is ideal. There are plenty of proprietary compost bins for sale at garden centres but you can use any kind of container that is large enough and has vents that allow enough air to flow through it, and also allow excess water to drain off. To make effective compost you will need a container that can hold at least 150 litres or more - 300/400 litres is ideal. Solid sided containers will also work if the contents are turned more regularly. Small containers can simply be emptied out and refilled.

If you unable to turn your compost and have enough space, a heap can simply be accumulated in a spare corner of the garden. However this will be much slower to decompose. It will need to be left for at least a year or more, after which it will still produce perfectly good compost.

Covering the compost heap helps to conserve moisture and prevents it drying out, as bacteria and microbes will stop working if the contents get too dry. Covering also prevents heavy rain causing water logging.

The key points to remember are:

  • Keep Moist: Make sure there is enough moisture to allow good bacteria to thrive but not so much that the pile becomes waterlogged and slimy.
  • Keep Warm: Cover with an old waste carpet or with cardboard (weighted down) to keep the heat in and the heavy rain out.
  • Mix Well: Turn the heap regularly with a fork to ensure a good mix of ingredients and help oxygenate the pile. This helps speed-up the decomposition process.
  • compost heap completed

As the compost rots the contents will shrink down into a dark soil like structure. The compost will be ready to use when it is friable and crumbly and has a mild sweet smell. In mid-summer this can be a little as 12 weeks if the heap is mixed well and turned regularly. In colder seasons it can take as long as 6 to 12 months to break down.

The best way to use the compost is to spread it thinly on the surface of the soil where it is needed. A covering or two inches (5cm) will be enough to rejuvenate your soil and help improve the health and vitality of all your plants.

If you're not going to use it straight away, keep it in a shaded spot and cover it up to prevent the nutrients being lost.

Compost Heap Problems

Too Dry: Add more green material like hedge or lawn clippings and water well.
Too Wet: Incorporate scrunched up newspaper or shredded cardboard.
Too Slow: Turn regularly. Incorporate more nitrogen-rich materials such as leafy green matter.
Smelly or Slimy: Not enough air or too much green material has been added. Empty out and fork back in, mixing in more shredded woody stems or cardboard.