If you can’t make some crumbly, dark brown garden compost my way, then all hope is lost. It’s guaranteed to tempt even the most devout compostophobes, compost-making virgins, and despairing “it turned into stinky black sludge” wannabes. With my cool, slow way of making compost, failure isn’t an option. What you’ll get is compost to energise your soil, perk up your container plants, and add magic to a homemade potting mix. If you’re imagining lists of dos and don’ts, hours spent mixing great steaming mountains of rotting vegetation, and nightmarish rodent invasions, don’t panic. This isn’t the way weightlifters make compost – this one is for squeamish wimps.
You’ll need at least two Dalek-shaped plastic compost bins – see if your local authority is offering them – with a 70-80cm diameter base. These don’t need panels to get the compost out. You also need a patch of soil – in sun or shade – where you can stand them, sheets of fine wire mesh to put your bins on – they should be wider than the bin base, and some bright red “compost worms”. Cadge these from a friend’s bin (or manure heap), or visit a tackle shop; a margarine tub’s worth is ample. Pale, sluggish earthworms aren’t for this job, so don’t dig them up. And you’ll need to feed your bin with kitchen, garden and household waste.
As rules go, there’s one: each time you feed your bin, aim for a 50:50 mix of greens and browns. Greens are sappier materials containing lots of water; think young annual weeds, vegetable peelings, apple cores, banana skins, lawn mowings (from weedkiller-free lawns). Browns are tougher, drier materials; think toilet roll tubes, scrunched cereal boxes, used paper kitchen towel. A tear test checks whether card packaging is coated in plastic film, which won’t rot. Remove sticky labels on cooking apples, or they’ll bug you later. Suffice to say that glass, plastic and metal should be recycled, not composted.
To keep adding a steady, balanced mixture of greens and browns, I find that a container indoors fills up with the right balance of each, without even thinking about it. Don’t fret: if you can only add greens one day, pop browns in the next. This is composting for busy wimps, not nitpicking nerds.
To get going, lay a mesh sheet on a clear patch of ground and sit your bin on it. The mesh stops rodents burrowing up inside the bin, and allows worms to come and go (they’ll retreat underground in a big freeze). For the first three weeks, add as much 50:50 mix as possible, building a good layer in the base. You don’t need to turn or lift anything, just keep adding more. A few handfuls of soil, or compost from a neighbour’s bin, unleashes the microscopic army of fungi and bacteria that help create compost. Keep everything just moist, but don’t drown it.
It’s then time to bring on the workers: orangey-red, pale-striped and thrashing compost worms – often called brandlings or tiger worms – that live among decaying organic matter. Add them to the mix in your bin, and relax. They’ll quickly get to work, eating their way through anything that rots. In a month or so, peel back the top layer and you’ll see them munching around; if you take the lid off at night and put your ear to the bin, you’ll hear their labours. Keep adding more 50:50 mix, until it eventually fills the bin. (Hint: scrunching card/paper into balls does more than ease tension: it adds air-filled pockets to the mix, soaks up excess moisture, and provides a worm hangout.) Worms work faster during warmer weather, only slowing up in cold spells – last winter was so mild that mine kept going non-stop. If worms gather around the top of the bin, crack the lid open at night so any discontents can slide away.
When a bin’s full, cover its contents with old leaves or lawn mowings, put the lid on, and let it be for 12-18 months. The worms will keep working, but as their food supply dwindles, they’ll depart into the ground. When you next remove the lid, the level will have sunk, and dark brown gardener’s gold awaits. Don’t forget: as you leave one full bin to mature, start filling the one next door, adding a few handfuls of the wriggling workforce.
To reach your compost, wiggle the bin loose and lift it off. The earthy crumble is a mix of decayed material and worm casts, which means it’s rich in plant foods and natural ‘growth boosters’, so use it sparingly. You can work it into your soil (two handfuls per square metre) or work a 0.5cm layer into the top of permanent potted plants. Much of mine is sieved and mixed 50:50 with leaf mould, to make a potting mix. If you can’t use it straight away, don’t leave it out in the rain, just bag it up.
John Walker is a gardening and environment writer. You can read more here.
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