At my time of life – on the nursery slopes of middle age, thank you for not asking – I’m meant to have bought a sports car (I don’t drive) or an expensive leather jacket (I’m a vegan). Instead, I’ve invested in my first compost bin. And, my God, I have never felt so alive.
Admittedly, it’s no ordinary compost bin. It’s a “hot composter”, a space-agey cuboid of moulded black expanded polypropylene that weighs next to nothing but cost me £150. Which is eye-watering for something that looks like the missing link between the monolith in 2001: A Space Odyssey and an oversized dog poo bin.
Yet I couldn’t be more besotted by my HotBin, the sleekest, sexiest bit of kit ever declared Gardening Product of the Year by the Royal Horticultural Society.
But, then, composting is hot right now. Last month, Gardeners’ Question Time panellist Matthew Wilson admitted in all seriousness, to barely stifled giggles from the audience, that getting a hot composter had changed his life.
As gardens slide into dormancy, there’s no time like the present to get a mulch going: tomato plants have given up their final fruit, raspberry canes want cutting back and the threat of frost is blackening off the dahlias, so there’s plenty of wilting greenery – not to mention the wet drifts of fallen leaves – that could all be rotting down nicely in a heap. A hot composter just accelerates the natural breaking-down process: garden waste that would normally take a year to decompose into crumbly, sweet-smelling humus can be ready for harvesting in 30 to 90 days.
As an amateur “yardener” – mine’s a small, southwest-facing patio with raised beds arranged in a petite horseshoe – I hoped the latest HotBin, a 100-litre “mini” – would give me somewhere to stash all those end-of-season clippings and keep me in nutrient-rich mulch.
What I never expected was that hot composting could become an all-consuming hobby, and that it would bring out the demon in me.
Within the HotBin’s airtight recess, I prepared the perfect cocktail: one part garden and kitchen waste, one part shredded paper (soaks up excess moisture), and one part what the supplier referred to mysteriously as “bulking agent”. This turned out to be wood chippings, the kind that usually clog up garden centre growbags.
Slowest of all the ingredients to decompose, the chippings create tiny but vital air pockets that trap the heat emitted by the busy bacteria, raising the overall temperature to sauna levels, ideally somewhere between 40C and 60C, the optimum window at which everything cooks down. Even when it’s freezing outside, inside the HotBin it’s totally tropical.
That’s the theory – but the practice? Like a tragic middle-aged divorcee astride his Harley, I was raring to go.
First, I started a collection of veg ends and peelings before raiding the fridge for leftovers and the weepy contents of the chiller drawer. I scoured kitchen cupboards for out-of-date goods (the harvest festival’s loss is the garden’s gain). I brewed more cafetières than I could drink just for the coffee grounds.
In the garden, I uprooted my tomato vines, deadheaded the roses (that was a first), and even studiously weeded between paving slabs, all in the name of amassing enough matter to get the bin revved up.
In a bucket, I mixed in handfuls of dead leaves, torn-up bank statements, even wine corks (minced by hand!) – known as “browns”, which, along with the all-important bulking agent, aid aeration. Tipped into the bin, it looked like a salad fight in a branch of Paperchase.
Then I waited. After a day, the HotBin’s built-in thermometer was in the low double figures, barely above ambient temperature. I lifted the lid. A cloud of fruit flies flew up in my face. Condensation dripped from the grille. Peering in, it all looked sopping wet, rather than hot and steamy.
It whiffed a bit, too. After another two days, a layer of greyish mould was developing.
For advice, I approached Rob Smith, winner of the BBC’s Big Allotment Challenge, who has been a keen hot composter for three years.
“The trick is to keep the bin topped up. It’s a hungry beast. It needs a fair amount of scraps inside just to get warm,” he said. “But once you’ve got it going, it ticks over nicely, even in winter. When it hits 50C or so, the little fruit flies don’t last long. The trick is to open the lid as little as you can. I’ll fill up a kitchen caddy before I think of adding it in.”
So I redoubled my efforts, going slightly mad in the process. Having swept my street for the leaves, I offered to take those from a neighbour’s garden. I pulled weeds from community flower beds. I blunted secateurs by clipping dozens of leathery, spear-like leaves blown off my cordyline.
The HotBin can handle human hair, so I did a tour of the plugholes. I tipped in the dusty contents of the vacuum cleaner. The instructions advise against this (plastic microfibres in carpets won’t break down) but, I reasoned, where’s the harm? I’ve got parquet flooring.
Rather than bin my fruit peel at work, I brought it home; banana and satsuma skins and apple cores, snipped with desk scissors and wrapped in those compostable wraps that magazines now come in (it’s a lie that they decompose; they don’t, and they snag things up when giving the compost a stir). I scavenged extra peels off colleagues, and scavenged for used tea bags in the office kitchen. A colleague wondered if I hadn’t developed “obsessive composting disorder”.
But in a few weeks’ time, my efforts should pay off – in spades.
There’ve been a few snags. I wish I’d put the HotBin on bricks, to better reach the drainage tap from which trickles (drips, more like) a brown, nutrient-rich leachate that can be used as liquid fertiliser. Early on, the local foxes took a shine to the bin’s adjustable air vent, sinking their fangs into the sides and spitting it out.
Also, it’s only been a few weeks since I started and, before I’ve even opened the compost drawer to check on its progress, I’ve gone through an entire bag of bulking agent.
I’m going to have to invest in a wood chipper now, aren’t I?
- The HotBin mini (£150) is available from hotbincomposting.com