The magic ingredient for food waste composting - dry woodchip
The ‘tricky’ part of composting food waste is the first stage - high nitrogen materials, like food waste, are ‘putrescible’ i.e. they are wet and tend to start breaking down, sometimes even when still in the caddy in the kitchen, and start to smell and ooze liquids, especially in the summer; worse, they attract flies. One solution is to empty the caddy daily and mix with dry woodchips, and, or sawdust and to get the material as quickly as possible through the hot, volatile, first stage of composting. The other possibility is to use the Bokashi system, and this is used by some community projects as a way, principally, of controlling odours where caddies are left out for a weekly collection round. (separating out food waste for collection has stopped rat infestations on estates in London where this system has been pioneered by the community projects involved )
Getting the mix right from the start is really important with food waste composting. You really cannot leave stuff lying around in buckets and going all smelly and anaerobic – it makes it much more difficult to start composting it aerobically.
- Get all materials composting as soon as possible
- Get the mix right – a simple rule of thumb is, one third
cooked food, one third fresh peelings etc and one third dry woodchip.
Because materials are so variable with regard to moisture and air content
you may have to play around with these proportions until it works optimally
your situation.
- The dry carbon fraction is also variable – ideally
you want a mixture of particle size from sawdust to large woodchips.
- Adding
cardboard to these systems is not a good idea as it tends to ball up in a
tumbler and clog up other systems.
Small amounts are fine, just don’t use this stage as a main route
for carboard or paper. You can add more paper and cardboard to the
maturation stage though.
- Add a bucket or two of compost when you first load
the composter, preferably from a food waste composting system, to kick-start
the process by adding loads of microorganisms.
- Loads of heat is produced, when you get it right
and so the volume of the contents drops dramatically,as much of the volume
of the material is water and is released as vapour, so you shouldn’t need
absorbent materials once you get the hang of it.
- You can recycle the woodchips by sieving the
contents into a maturation bin, that way you get to cycle the
microorganisms and build up the right ones for your system.
