On a roll with Compost Tumblers

The Great Green Team

16 February 2022

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Compost Tumblers

On a cold day in February we interviewed Michael Kennard from Compost Club in Lewes, East Sussex, about the role that Compost Tumblers play in creating gold-standard compost.

What exactly is Compost Club?

The club’s mission is to help build ‘healthy soil to produce healthy plants for healthy humans and all life on earth.’

Working on a subscription basis, the club offers a double service, taking in people’s food waste and turning it into quality compost.

Members – households and businesses – are given a 30-litre bucket to fill with food waste, which gets collected every three weeks and turned over time into compost. Members receive compost in the Spring and any surplus is sold.

‘This turns the ethical choice into a convenient one,’ says Michael. ‘Often the convenient choice is a negative one when it comes to ecology.’

The service is so popular that membership is full and there is a waiting list. The club is crowdfunding to double the number of households they serve to meet the growing demand and there are plans to develop more sites.

Living compost that regenerates soil

The Lewes site currently recycles 160 tubs of food waste every three weeks, around 80,000 litres per year, but the hope is to expand to a point where they can recycle 60 tonnes of food waste per site per year, serving 240 – 300 households in the Lewes, Brighton and Hove area.

Michael is enthusiastic about the quality of the compost that is produced.

‘It’s full of the organisms which give life to the soil. We call it Living Compost Inoculum but we’re thinking of rebranding it as Zero Waste Compost because it literally is made from waste and turned into something really valuable – living compost that regenerates soil. I’ve looked at it under the microscope – there’s bacteria, protozoa, fungi, nematodes….right up to bigger things like worms.’

Michael also runs workshops and courses for community groups to spread the message so the whole community can grow – literally – along with the club.

How did Compost Club come about?

Michael has always had an interest in gardening and been engaged environmentally.  He and his wife got an allotment and composted all their own food waste. When the first lockdown hit, Michael was growing on a market garden scale and needed a lot of compost.

‘If I was looking to regenerate soil, it had to be of a certain quality, but it just wasn’t available. The only option was to make it, so I needed it on a bigger scale with more food waste and other input.’

He quickly had more people asking him to take their food waste than he could cope with, so the idea for the club came into being. Compost clubs are more common in America but there are not many in the UK. ‘There’s a massive gap for something here,’ says Michael.

The 24 Compost Tumblers on the club’s Lewes site have proved very helpful.

‘We’ve been able to get through a lot more volume because the Tumbler’s turning handle saves time and makes turning effortless, so I’m able to go along the row turning the handles. They also hold moisture and the vents mean the contents can breathe.’

Winter is a particularly busy time as the composting micro-organisms are given a helping hand to keep working efficiently in cold temperatures.

Getting ready to tumble

Food waste is put through the Tumblers mixed 50/50 with wood chips. Wood chips are used because a high volume of carbon is needed to balance the high nitrogen content of all the food waste. When the waste has been tumbled and broken down enough it joins the end of a windrow. From there it continues breaking down, getting turned occasionally and gradually progressing down the windrow until it reaches the maturing stage. Fungi proliferate the pile and worms are added for a finishing flourish. The site is a hive of activity, with different tumblers and maturation bays all playing a part.

Michael adds that many people are now adding biochar to their compost bins. This is a product formed by pyrolysis, whereby scrap wood is burned without oxygen. Biochar provides pure stable carbon, which locks carbon in the soil.

Waste is a human thing

‘It’s beautiful stuff,’ says Michael. ‘It boosts carbon in the soil and if you use the no-dig method it stays there.’

The club hopes to form links with agriculture providing food for the area. Compost Club would intercept the waste that is produced, before exporting the finished compost back to the fields to be used instead of inorganic fertilisers.

‘So you create a closed loop with no waste, which is how natural systems work.  Waste is a human thing. I’m trying to become a giant earthworm, I guess!’

Members come from all walks of life. One is a local footballer who signed for Lewes and had heard about the club on social media. He got in touch with Michael and there is now a community garden at the stadium, along with a couple of Tumblers composting the food waste created there.

‘In Brighton we’re quite lucky, it’s a green city with a lot of green-minded people and businesses,’ says Michael.

Any composting tips for other would-be earthworms?

Michael says he sometimes sees people with a Green Johanna who have added food waste but not provided enough carbon so the mixture is too wet. They have too much nitrogen and not enough carbon.  In such cases, he suggests adding carbon in the form of shredded card and paper.

Again, he recommends wood chips as they ‘last longer, hold structure and create pathways for the air. If you add a bucket of food waste, add a bucket of wood chippings.’

He adds that the compost mix should contain 50% moisture. A test is to take a big handful and squeeze tight – only a couple of drops of liquid should come out.

And don’t forget to turn your compost to get plenty of oxygen into the mix.

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