There are many satisfying parts of my grower’s job, but none ticks quite so many boxes as turning the compost. On the scale that we are growing on our urban site in Hackney, turning the compost is done manually: our composting facility is much bigger than a domestic bin but it’s not big enough to warrant a mechanical aid.
The job’s one that I don’t have much chance to get in on these days, as it’s also the perfect task to hand over to a volunteer, or two. A wonderful learning opportunity, compost tells the story of nature’s progress, from fresh organic matter, through decomposition, and into a near to perfect food for the soil. I almost feel cheesy when I get going on how miraculous it is.
On an organic market garden making compost is crucial. Using it to feed the soil means that we can grow much healthier crops and we don’t have to rely on artificial fertilisers. Sadly, it’s impossible to make as much as we need – taking, as we do, so much of the soil’s nutrients away every time we harvest, very little ends up back on the heap. And we use those beds pretty intensively.
But we do manage to make about half of our requirements, so today, I turned the compost. Rolled up my sleeves and got totally stuck in. A warming job for a cold winter’s day.
Our system runs on three bays using the cold composting method, (cold compost = we add material as it becomes available, rather than the much faster hot composting method where you layer up the different ingredients in one go). The first bay is the active one into which everything goes. As well as organic material coming off the sites, we also use some of the organic waste and card from the box scheme, so we have a good mix of nitrogenous (greens) and carbon (browns) ingredients. You want to get the proportions right, otherwise rather than a sweet-smelling soil improver you can get a foul-smelling sludge, the result of anaerobic (= air-free) conditions. Or, if you have too many browns, your compost heap won’t seem like it is doing anything at all.
The second bay is for turning your compost into once the first bay is full. We aim to turn ours every two to three months or when it has filled up – the speed of break down is very much dependent on the weather: nice warm days get it going much faster. By turning it, you add air to the heap and give those micro-organisms in there a better chance of doing their job of decomposition. You’re also able to move the outside areas into the middle where it gets good and warm (and you might just find some of those missing trowels you were looking for…).
By the time this bay is ready for turning again (2-3 months later, again depending on the time of year but also on the need to turn the first bay again), it’ll begin to resemble what you might consider compost, looking quite soil like. You should see loads of life in there – mostly worms but slugs, wood lice and other creatures you can and can’t see play prominent roles. Don’t be surprised if you find a mouse in there too – it’s a lovely warm spot to hang out in. Turning the compost, being mindful of hurting possible mammalian inhabitants, has the added advantage of sending the larger squatters on their way.
And then there’s the final bay, into which the second bay is turned. Now it is totally recognisable as compost, and after just a month or two it’ll just need to be sieved to remove any un-composted sticks, before being used around the site.
It’s a physical job doing the turning and a great opportunity to check up on how it is doing and making necessary adjustments – adding more card if too wet, some water if too dry. Totally and utterly satisfying, especially knowing how much the soil is going to love it when it’s spread out across our sites.