Page 34 - ALG Issue 4 2023

5composting
STEPS TO QUICKER SEASONAL COMPOSTING
The time of year is approaching
when the temperature falls to below the active range of the mesophilic composting organisms (10-45°C) and the composting process will slow or cease, until the temperature rises in the spring. In this article we look at ways to speed up the composting process to make best use of time available before the winter and at ways to keep the allotment bins warmer and active during the cold season.
1 INSULATE THE BIN & CONTENTS TO RETAIN THE HEAT GENERATED
BY MICROBIAL ACTIVITY
Some commercially available bins
are supplied already insulated e.g., Hotbin, Jorraform and Aerobin, while
an insulated jacket can be purchased for the Green Johnanna to provide winter warmth and to assist hot composting during the summer. If you use pallet bins or other wooden bins, remember that size is important - the bigger the better! Bins can be insulated with thick polystyrene sheets or the more environmentally friendly wool packaging; both can be covered in plastic. Similar material can be used foralidtothebin,butacoveronthe compost should also be used such as a commercially available compost duvet. Carpet can also be used to insulate both the sides of the bin and layered on top of the material. And cardboard could be used to line the inside. Plastic bins can be provided with temporary insulation using two or three layers of bubble wrap or carpet. We also use this to overwinter our wormeries and, if carefully stored, it can be reused for several winters.
Five litre plastic containers filled
with hot water and buried in, or put on, the compost in an insulated bin, can be used as hot water bottles
to add warmth, helping to raise the temperature. These will also provide a boost to a newly made bin.
2 CUT, TEAR OR SHRED THE MATERIALS
If you want to compost quickly, expose the maximum surface area of the organic material to the microbial action by shredding, premixing if possible, mowing with a lawn mower or manually cutting using long handled shears. Cutting into 1-2inch lengths and turning it every second day for three weeks will produce immature compost quickly,
but it is a lot of work. I compromise by cutting the material to about six inches in length and aim to turn the bins weekly for the first month. If started now, in Leicester, this will produce compost ready to use as a mulch in the spring. Just mixing the contents a couple of times will help aerate the bin. I use a manure fork to turn my compost as it is lighter that a digging fork. Saving green and brown material separately until you can fill the bin in one go is advisable.
If you do not want the effort of turning the contents, it is possible to compost in about a month without turning if the bin is of sufficient size and layered to allow passive aeration and encouraging or introducing more composting worms by adding manure layers, from a wormery or by buying them.
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Turning the compost will help break up lumps which might become anaerobic, while introducing oxygen into the mix
and creating free air spaces, allowing
the microbes to multiply. The addition of wood chip or similar materials as a bulking agent will help maintain air spaces.
KICK START THE
DECOMPOSITION WITH AN ACTIVATOR
Adding a layer (or two) of soil or finished home compost will provide additional microbes by adding mature compost or local soil. Natural activators can also be added to provide additional greens. Chicken and farmyard manure will also introduce microbes and worms but, if using equine manure, ensure that herbicides have not been used on the grazing paddock. I use coffee grounds, and comfrey, nettles and freshly cut grass when in season - seaweed is also effective.
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In the summer, the contents of plastic bins are likely to dry out and require watering, but this can also be a problem with any bin including during the winter if it is covered to retain heat and prevent waterlogging. The moisture content can be checked and water added
when turning or adding waste to the bin. However, during the winter and particularly wet winters, the bins can become too wet.
High moisture levels can result in filled air spaces, giving rise to undesirable anaerobic conditions as well as causing a reduction in the heap temperature and a slowing of the composting process. The moisture content can be checked by squeezing a handful of compost. If
it fails to make a ball, it is too dry; if it makes a ball and a small drop of water appears, it is just right and if it makes a ball and lots of water runs between your fingers, it is too wet. Add more browns e.g., cardboard, shredded paper and dry autumn leaves.
Rod Weston
MAINTAIN THE MOISTURE
LEVEL
AERATION
A good supply of oxygen is essential for aerobic composting. The airflow through the base can be increased by adding a layer of sticks, twigs, straw or scrunched cardboard at the bottom of the bin and/or lifting the material off the ground by providing a pallet base
to the bin to allow a layer of air to enter under the bin and slowly move upward through the contents. Inserting one or more plastic downpipes under or down through the contents will also increase the airflow but during winter this would be cold air.
Natural activators can also be added to provide additional greens. Chicken and farmyard manure will also introduce microbes and worms
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Rod Weston is an organic master compost expert, who operates a composting demonstration
site with over 30 composting bins, wormeries and cooked food composters at Stokes Wood Allotments in Leicester. He is also author of ‘A Gardeners Guide to Composting Techniques’ shortly to be published by Crowood Press.
34 Allotment and Leisure Gardener