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 environment friendly way of addressing both of these problems by converting garden waste into a soil building plant food.
If you are a vegetable grower composting is especially important as the nutrient requirements of fruit and vegetables are high meaning you must constantly replenish your soil with new nutrient rich material. Making compost works by allowing the parts of the plants you don’t eat to rot down naturally to produce a dark, crumbly material which can 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
Compost can be made in a simple pile in the garden but a compost bin is more useful as it keeps the heap tidy but also helps keep heat in which speeds up the process. There are a choice of different types of compost bin from enclosed plastic units for small gardens to larger timber structures if you have more garden waste you wish to 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 fruit and vegetable 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.
Types of compost bin
There are a number of different type compost bins available ranging from enclosed plastic tower systems for small amounts of material up to large 2 or 3 bay wooden compost bins 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 but 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 is 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
Compost need 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.
Grass mowings Green plant debris (leaves, stems, weeds) Kitchen fruit and vegetable peelings.
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 and produce a perfect crumbly compost; the smaller and better mixed the particles of carbon and nitrogen the faster they will break down.
Most gardeners, however, add compost to a heap when they have material available which usually results in a more layered pile. In this case try to add alternative layers of green and brown material mixing them where you can.
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 to add 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.
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 compost 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 is helpful under the carpet to help 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.
Soggy, smelly compost
“My compost bin smells!” is a very common complaint even more likely when using enclosed plastic compost bins. The reason is 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 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 as it creates a fiberous mat that moisture simply drains through. This material will also be the culprit if you have uneven finished compost as you create pockets where moisture and heat is lost.
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 which will be mixed in and benefit your garden when the finished compost in finally spread.