You can still make compost during a cold frozen January. But whatever we put in our bins the whole composting process will take a bit longer just now.
As I write, the temperature in my open New Zealand box struggles up to 5C℃ once I’ve thrust the thermometer through a blanket of snow. My well-covered and insulated compost bin is only 2C better. But this is much higher than air temperature.
You simply can’t achieve the summer’s 30-35C even if you place the composter in a sunny spot and fill it with a 50:50 mix of green sappy waste and brown fibrous material. Also composting only works well when surplus moisture from kitchen scraps, grass clippings or weeds is absorbed by drier fibrous material and this fibre breaks up the dense, airless mass of soggy waste.
You probably won’t have brown garden waste just now, but to prevent a soggy smelly mess of rotting kitchen scraps, mix in crumpled envelopes and paper or torn up card instead.
And an occasional handful of garden soil adds in energising microbiome.
Try to keep the composter well insulated. With a New Zealand box, cover the heap with bubble film or an old piece of carpet and don’t use snow as a duvet, like I lazily do! Use a thick layer of card or old carpet to cover the heap inside a composter.
As a final touch, to prevent its lid from freezing onto the bin, first hang an old plastic bag over the rim.
There are other ways of composting raw kitchen waste over the winter.
One is a Hotbin, unfortunately costing around £179, but it is sealed, so can take cooked food waste.
Or you might prefer a cheaper wormery. Compost worms keep slowly working away when it’s warmer than 5C. Mine are avidly demanding their dinner in my shed.
I certainly wouldn’t be without wormcast for top dressing containers on the patio. This finished wormcast is much richer than traditional compost, especially as worms add 50% more nutrients to the waste during digestion.
There are several different types of wormery available, and you get set up and maintenance advice.
Alternatively, you could try composting in a bag. You’re reusing spent compost and kitchen scraps while reducing your gardening bill. Composting in a bag is a great way to refresh last year’s commercial compost.
Use a stout plastic bag. Start by piercing the base with a fork for drainage and then put in a layer of compost, 5-8cm deep.
Cover thickly with kitchen waste and sprinkle a teaspoon of compost activator on top.
Then cover with a second layer of compost to prevent any smells from escaping.
Continue with these alternate layers until full, then firmly tie the top.
Put the bag in the garden to let surplus liquid drain into the soil. After a few months, mix with fresh commercial compost and your plants will love it.
You could try your hand at a fine old gardening technique: trench composting. This works especially well in parts of the veg garden earmarked for tender crops. It was traditionally used for runner beans where you need a long trench. But it would also work for courgettes, cucumbers or squash.
Dig a hole, one spit’s deep slightly wider than the planting area. Tip the contents of your kitchen caddy along the trench to a depth of 5-8cm and cover with a thin layer of soil.
Continue till the trench is full, ensuring the top layer of soil is at least 8cm deep.
Worms will get on with the job, just like in a wormery, and everything will gradually sink as the kitchen scraps rot down.