Composting – is it just a load of old rot?

Just to my left, as I’m writing this, is a bookshelf filled with books about composting. If you’ve followed this blog for any length of time you’ll know that we’ve tried almost every way there is of making good compost; and each of them has advantages and disadvantages. The one thing I can say with absolute certainty is that the heap in the picture above is a rubbish heap and not a compost heap. The computer software saying – “garbage in, garbage out” applies every bit was strongly to compost. I’ve even seen an abandoned bike rusting away on a compost heap.

The favourite starting point for most of us is the one you make from wooden pallets. The advantage is that it’s pretty much free to make and it will produce compost. The downside is that the open slats allow cold air and rats to get in, and if there’s any trace of food waste they’ll come hunting for it. Rats are an ever present nuisance and we just have to accept that. You can line them with chicken wire but rats often dig in by tunnelling underneath and you’ll soon discover when turning the heap that the tines of your fork will constantly hit the netting. Our neighbour bought himself a fabulously expensive hot-bin made from expanded polystyrene and the rats simply ate through it. As for the conical polythene ones that you buy at garden centres or from the council – I can’t say because we’ve never had one – but I hear the rats still get in from underneath.

On the far left above is my version of the California Cylinder which, – when there’s plenty of green waste around – will go like a train. It’s made by forming two concentric cylinders of sheep wire and then inserting thick cardboard into the gap between them. You can also build in a chimney to pull heat through. In one of our gardens, when we cleared it of weeds, we had four in a line steaming away merrily and turning out fabulous compost. The next year we had far less green waste and they were not so successful. The other disadvantage is that it’s all but impossible to turn the heap – it’s better to pull the wire and cardboard off, set it up again somewhere close and refill it with the turned compost.

The simplest composting method of all is the leaf mould heap, like the one in the right hand photo, which is a single cylinder of sheep wire filled with as many leaves as you can press down into it. It takes a year or two but it always works. We find that we can grow a great crop of cucumbers on the heap during the summer while it rots. Even open heaps will work eventually, but then you really have to turn them very frequently and they’ll grind to a halt as soon as the weather gets cold. In the end I built a large four bay composting arrangement with removable fronts which works well for us and makes turning easy -still hard work, though!

Composting is a seasonal cycle

The big challenge is that composting works best when you control the ingredients – mixing green and brown waste and turning regularly. So during the winter months there’s nothing much going in except for veg peelings and the like. Winter heaps don’t often heat up very much, and unless they’re well laced with torn up cardboard and paper, they tend to get anaerobic, wet and smelly. Even in a well managed winter heap, you’ll find that it’s worms doing most of the work. Worms are wonderful. They appear out of nowhere, chew up your waste and turn it into gold – very slowly. In the spring if the heap or the ambient temperature gets warmer they’ll move off somewhere more comfortable without any intervention on our part.

There are two peak green waste seasons – early summer when the remains of winter crops like broad beans go in; and autumn when bean vines and all the rest are cleared away. We move the winter heap with its worms to the next bin and then layer the abundant green waste with any sort of carbon we can get our hands on – cardboard so long as it’s not plastic coated, any sort of dried or dead grass, leaves and – interestingly – wood chip. Just this week our bin reached almost 60C with several 2″ layers of wood chip incorporated. We were confident in adding wood chip because we noticed that we get through around 25 barrow loads every year just topping up the paths. It rots down much quicker than you’d think. We’re lucky because the local council bring wood chip and leaves on to the site during the autumn.

But there are other additives that are invaluable in a compost heap. We use horse manure and even seaweed when we can get it. The last load of seaweed we brought down from the Lleyn Peninsula in North Wales where we’d been on holiday. It stank to high heaven and was full of flies and sandhoppers so it was an uncomfortable 200 mile journey with the windows open; just as it always is with the still warm horse manure that we use in the hot bed. If there’s any spare we add that to the compost as well because it’s so rich in nitrogen and carbon – already mixed.

We also occasionally use chicken manure pellets to steam things up a bit, and drench the heap with liquid seaweed feed now and again if it feels too dry. Control of the moisture level is crucial to success and one of this year’s jobs on the to-do list is to roof over the whole line of bins so we can harvest the rain falling on them and control the temperature and moisture level more accurately.

Of course the finest additive of all is human urine which combines bioavailable nitrogen and moisture at the same time – but don’t overdo it and make sure you’ve agreed with your partner that it’s OK to clutter up the bathroom with a jug and a five litre ex vinegar container marked clearly “Bio-hazard” . We tell everyone we talk to that we’re doing it because it’s an amazingly effective preventative against crop larceny – because they never know which ones we’ve just anointed!

What not to add

Obviously any cooked food and or meat – although I’ve occasionally left a dead rat to compost down because it seemed only fair. Winter heaps should not contain noxious weeds like bindweed because they don’t get hot enough to kill seeds and roots . a very hot summer heap – if it reaches, say, 60C would kill pretty much anything – but you never know. We err on the side of caution always, having introduced creeping buttercup into one of our past gardens via horse manure.

More particularly after wasting many hours picking bits of so-called compostable material out of an old heap; we no longer add those green caddy liners nor any teabags. We open teabags to extract the tea leaves and the compostable bags which seem never to rot, go to landfill. Even worse are the big ticket tea temples that are part of the USP of Teapigs brand. Sorry guys – without a commercial (very hot) process they appear to be invincible; clogging up the beds and any rake you might use. I actually ran an experiment on the little coir disks wrapped in mesh which purport to be green – and they don’t rot either. When it comes to greening up horticulture it pays to be careful – not everything it says on the packet comes to pass! And don’t ever put in a thick layer of grass mowings unless you’ve allowed it to wilt first in the sun.

That’s it really – the sad sum of my composting experience in a thousand or so words out of the fruits of which we can make maybe three cubic metres of compost and one and a half of leaf mould every year. Marvellous stuff ‘though – and so much better than anything you could buy in a shop.

Author: Dave Pole

I've spent my life doing a lot of things, all of them interesting and many of them great fun. When most people see my CV they probably think I'm making things up because it includes being a rather bad welder and engineering dogsbody, a potter, a groundsman and bus driver. I taught in a prison and in one of those ghastly old mental institutions as an art therapist and I spent ten years as a community artist. I was one of the founding members of Spike Island, which began life as Artspace Bristol. ! wrote a column for Bristol Evening Post (I got sacked three times, in which I take some pride) and I worked in local and network radio and then finally became an Anglican parish priest for 25 years, retiring at 68 when I realised that the institutional church and me were on different paths. What interests me? It would be easier to list what doesn't, but I love cooking and baking with our home grown ingredients. I'm fascinated by botany and wildlife in general, and botanical illustration. We have a camper van that takes us to the wild places, we love walking, especially in the hills, and we take too many photographs. But what really animates me is the question "what does it mean to be human?". I've spent my life exploring it in every possible way and the answer is ..... well, today it's sitting in the van in the rain and looking across Ramsey Sound towards Ramsey Island. But it might as easily be digging potatoes or making pickle, singing or finding an orchid or just sitting. But it sure as hell doesn't mean getting a promotion, beasting your co-workers or being obsequious to power, which ensured that my rise to greatness in the Church of England flatlined 30 years ago after about 2 days. But I'm still here and still searching for that elusive sweet spot, and I don't have to please anyone any more. Over the last 50 or so years we've had a succession of gardens, some more like wildernesses when we were both working full-time, but now we're back in the game with our two allotments in Bath.

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