OUR compost bins work faster when we keep them hot. This partly depends on air temperature. So whatever we do in Shetland, composting is slower than in Eastbourne and that’s a snail’s pace compared with Malaga.
And the time of year is also critical. As I write, my New Zealand box registers 15C, twice today’s air temperature, but only a third of what I’d expect in the summer.
The sun is pivotal. With our weaker sun in Scotland, we need as sunny a spot as possible for our composters; partial shade is not ideal. You can, of course, make compost behind a shed, but don’t expect a result any time soon.
A bin’s shape also matters. The rounder the better, as the sun shines on most of it during the course of the day. It can never reach one side of a square one.
When filling the composter, try to ensure there’s a good mix of green sappy material, such as weeds and kitchen scraps, with brown, woodier material, such as paper and plant stalks.
Too much green gives you a soggy, smelly mess and virtually no composting occurs with only dry browns. A green-brown balance gives you a damp, healthy brew.
Also, compost activator won’t wave a magic wand and transform large lumpy bits of sprout stalk into mouth-watering compost. It gradually speeds up a reasonably working pile, but there are plenty of free methods to use.
The smaller the individual pieces you add, the better. This is because there are many more exposed edges for micro-organisms, such as bacteria, to work on. They then reproduce rapidly, leading to a larger workforce. At a later, cooler composting stage, creatures, like worms, also graze round the edges of materials and this extra food leads to an increase in their numbers.
So these larger populations produce quicker results.
Everyone knows that you get faster composting by turning the heap to inject fresh oxygen. This works with New Zealand boxes and can be done as often as your back can stand it. But small plastic units should not be treated this way.
Here there is fresh material at the top and finished compost at the bottom: the last thing you want to do is mix it all together.