This page is written by the Stevens Street team and is included as an example of Community comosting on an allotment site
The trial was managed by two allotmenteers
Ruth Halberda (Master Gardener) and Judy Burrage (Master Composter) plus David Robbins (MC) volunteering via the Garden Organic Master Composter initiative, with excellent support from about 20 allotment volunteers
Composting Trial (August 2017)
Hot composting is a well proven method designed to produce good quality compost - often in bulk but in a much shorter time period than the more common (cool) composting bin,
bay or heap. It is used by many organisations to process city green waste and by a growing number of community composting projects.
The incentive for the Stevens St trial was the need to process the large amounts of
materials cleared from well over 100 individual plots - particularly things like perennial weeds, and woody waste which aren't suitable for normal cool composting on their own heaps plus material from the common areas - and stored in dump bags / piles.
Ideally, this mixed ‘waste’ would be graded, composted and used on site - avoiding the cost, labour and environmental impact of hiring skips or getting it trailered to the local Recycling Centre.
It was important
that allotmenteers were involved and that any concerns about reintroducing ‘nasties’ like bindweed, mare’s tail and couch grass were addressed.
Basic research and discussions with other Master Composters suggested that Hot Composting would be worth trialling - the trick would be:
- getting the size and design right
(at least 1m3, in bays rather than an open heaps, wellmade with easy access and movable dividers to allow turning from one bay to another) - having the right mix (well chopped green/brown, evenly mixed with some accelerator eg soaked nettle tops
or rotted manure, correct moisture, well aerated, balanced pH levels) - reducing heat loss (well insulated top and sides to keep at 40-60oC for at least 3-10 days, measured daily with a long probe thermometer)
turning regularly (when it starts to cool, at least weekly)
- having enough extra feedstock to hand (eg 50kg/m3 to keep it active for two weeks) - maturing off (eg allow up to 12 weeks depending on
outside temperature, test for any residual nasties before using)
Note: Hot composting needs to exclude any cooked food, meat, fish, dairy or bread to avoid encouraging vermin
/ scavengers – unless using a sealed vessel. Perennial weeds should not survive if the high temperatures are maintained throughout the heap for at least three days.
(RW See Composting Food for more information on cooked food composting and for more information on weeds - Perennial