There are a few very basic dos and don’ts around composting that will ensure success.
The main question you will be asked is how the bins will be kept free of vermin, ie rats, and the simple answer to that is that it’s pretty hard to guarantee they will be rat free but by not putting any cooked food into the bins you are doing all that is possible to stop rats and other rodents as well as the urban fox.
A ratio of 2/3 nitrogen rich material (greens) to 1/3 carbon rich material (browns) is best to guarantee the heap warming up and so breaking down as fast as possible.
In order to guarantee a good heat in the bin it’s vital to keep the levels of nitrogen rich material (greens) at a good ratio with carbon rich material (browns) and the ratio that is most successful is around two thirds green and one third brown.
The best way to pile up the heap is to have layers of greens and browns. This means that, for example, there might be a layer of lawn cuttings and then a layer of shredded cardboard. The browns basically soak up excess moisture from the greens, ensuring the heap doesn’t become too wet which will lead to it being anaerobic and smelling.
There is much conversation around whether or not compost heaps ought to be turned often. The most vital thing in making compost is that heat is made in the heap to break down the materials in the heap. This will happen spontaneously as the compost worms get to work, but the heap will cool down after it has heated up. Turning at this point helps to reheat the heap. It’s worth buying a compost thermometer so that children can see just how warm a heap can get. There is also discussion to be had with children over the red compost worms that appear in good compost heaps and the difference between them and earthworms. If you are struggling to get worms into your heap, composting worms can be bought online.
Once your heap is full and you are regularly turning it to ensure it stays warm, it’s quite important to ensure it stays moist but not wet. Unless it is particularly warm it should keep itself moist enough with the condensation from the heating process, but it’s worth keeping an eye on in the summer. Equally in the winter you will need to put a cover over your heap, such as a tarpaulin. Please do not use old carpet as is traditionally used on allotments as this can contain chemicals that are present in fire retardants which you don’t want to leach into the soil.
Green to add to your bin
- Garden waste-green prunings and lawn clippings
- Peelings, although go easy with potatoes as they can shoot from peelings
- Uncooked veg such as the outer leaves of cabbages etc.
- Veg that has started to go off
- Fruit that has started to go off, but not too much citrus fruit
- Annual weed leaves but not if they have flowered as seed will be present
- Manure from chickens or farmyard manure
Brown to add to your bin
- Plain paper and cardboard that have been shredded lightly
- Egg boxes cut up
- Woody prunings chopped up
- Natural fabric such as old cotton or woollens
These lists are far from exhaustive and there are other things which people might add-it’s just a case of working with what works best with you. However there are a few definites that must never be added. These include meat as this will guarantee foxes and rats, faeces, manmade fibres and materials from an undisclosed source that could contain unpleasantries.
Leaves – in the compost or not?
Leaves can be added to your compost bin and they will break down, depending on what type of leaf they are. We’ll talk about what else you can do with autumn leaves shortly.
Image: Adding leaves to leaf mould box by far closer, on Flickr