How To Make Compost

Get composting! You can learn how to make compost in just a few minutes. If you enjoy gardening you will inevitably end up with garden waste you need to get rid of, while also needing fertilizer for your plants. Making compost is a practical, natural and environmentally friendly way of addressing both of these problems. It does so by converting garden waste into a soil-building plant food.

Composting is especially important for vegetable growers, as the nutrient requirements of fruit and vegetables are high. This means that you must constantly replenish your soil with new nutrient-rich material. By allowing the parts of the plants you don’t eat to rot down naturally, you end up with a dark, crumbly material which can then be added back to your garden.

It is a simple cycle: The plant takes nutrients from the soil to grow > the plant dies and breaks down > allowing the nutrients to be released back to the soil > which then nourish a new plant.

How to Compost

What to compost in a plastic compost bin

You can set up a simple compost pile in the garden, but a compost bin is more effective in a number of ways. A bin or other container keeps the heap tidy and also helps keep heat in, which speeds up the process. Quickcrop stock a range of compost bins which you can view at the end of this article.

What can you compost? You can compost any garden waste including vegetable or ornamental plant waste, weeds, grass clippings and leaves. You can also add raw kitchen waste including potato and carrot peelings, apple cores, tea bags and coffee grounds.

What can’t you compost? It is not a good idea to compost cooked food, animal waste, meat or fish or potatoes effected by blight. You should also avoid citrus peelings as the citric acid they contain will slow the composting process.

New zealand box compost bin system

Types of compost bin There are a number of different types available. Enclosed plastic tower systems will suit small amounts of composting materials. Large wooden compost bins with 2 or 3 bays will be more suitable if you have a large garden and need to dispose of a large amount of waste. Each type of composter will have its own advantages and disadvantages. As a rule of thumb the easiest and most forgiving system is a slatted wooden version, because it allows more air circulation.

The most effective solution is the New Zealand Box Composting system, which consists of 2 or 3 separate composting bays. The idea behind this system is that material is partially composted before being shoveled into the adjacent bin. This mixes the material and adds air, which starts a secondary stage.

How to make your own compost Good compost needs a mix of green and brown material at an approximate 50/50 ratio. Green material contains nitrogen and brown material contains carbon. These are the building blocks of fertile garden compost. Below are some examples of brown and green material to help you mix your compost heap correctly.

Green material Grass mowings, green plant debris (leaves, stems, weeds), kitchen fruit and vegetable peelings.

Brown material Dry leaves, cardboard and newspaper (not glossy magazines), woody plant prunings (chopped small), coffee grounds and egg shells.

How to start composting Ideally you want an even mix of the two materials. If you had a large shredder and a ready supply of green and brown ingredients, you could create a mix which would compost very quickly. This would most likely result in a perfect crumbly and dark brown compost. The smaller and better mixed the carbon and nitrogen particles, the faster they will break down.

Most gardeners, however, add compost to a heap when they have material available. This usually results in a more layered pile. If this is the case try to add alternative layers of green and brown material, mixing them where you can.

Compost added in layers to compost pile

Depending on the type of bin you are using and the time of year (outside temperature makes a difference), the composting process can take anything from 2 to 6 months to complete. It will be very beneficial to mix your materials at least once during the cycle. This adds air to the mix, which re-starts the composting process. Air allows the beneficial bacterial (who are doing most of the work) to breath and multiply, while mixing results in a more even finished product. Time spent mixing or 'turning' a compost heap will be regained when spreading the finished mix, as the material will generally be more even and easy to work. A good-quality garden fork can come in handy for this task.

Covering a compost heap If you are building an open compost heap, it is a good idea to cover it once it has reached the desired height. This is especially important in winter and in areas of high rainfall. A compost heap needs to conserve some of the heat it creates. A wet and cold heap will be slow to break down and will not reach temperatures high enough to kill off any weed seeds.

A compost bin can be covered with a lid or a layer of old carpet. A square of foam insulation board under the carpet helps to retain more heat.

Compost bin problems There are a few common issues many people have when producing their own garden compost. Most are down to an imbalance of green and brown material. I include some issue and solutions below.

Partially rotted food scraps compost bin

Soggy, smelly compost "My compost bin smells!" is a very common complaint. It's even more likely when using enclosed plastic compost bins. The reason is usually too much green material and not enough fiberous brown. To remedy, add crumpled paper, cardboard, dry brown leaves or other high-carbon ingredients.

Soggy compost can also occur in an open bin where too much rain is washed through, or if the compost bin is built on a site with poor drainage. Cover the pile as detailed above to protect against rain, and move or build an elevated base if the site is wet.

Dry compost Dry compost that doesn't appear to be breaking down is due to too much brown material. Carbon takes a very long time to decompose unless mixed with nitrogen-rich material. To remedy, add more green material like grass clippings - and mix well.

If you have large amounts of dry twiggy material, it will need to be chopped and mixed with your greens. Otherwise it creates a fiberous mat that moisture simply drains away through. This material will also be the culprit if you have uneven finished compost, as you end up creating pockets where moisture and heat is lost.

Compost Accelerator

Compost activators and accelerators You can add quantities of manure (poultry is particularly good) as the fungi, bacteria and nutrients they contain will be especially beneficial.

There are a number of 'off the shelf' compost activators like 'Vitax Compost Maker' (which adds nitrogen) or the excellent organic 'Compost Renew', which contains a special mix of beneficial bacteria.

'Rockdust' or ground volcanic basalt can also be added periodically to compost - a handful at a time - to add minerals. This will benefit your garden when the finished compost is finally spread.