Quite a while ago (like, 8 years ago!), I was buying some lucerne for the garden at the feed store at Albion Park Rail and I noticed they had a few large PVC drums stacked in the corner. I asked about them and they were waiting to be recycled, so I bought one for $25.
It was a struggle to fit the barrel and the lucerne bales in my little hatchback car, but I managed to get the lot home. I drilled some holes around the barrel to let air in and water out. About 5 mm holes are pretty good – much bigger and you’ll get pests in there and compost will fall out.
Using the DIY tumbling compost bin is dead easy. You just fill it with lawn clippings, manure, stable sweepings, leaves, comfrey, and garden prunings put through a shredder. I don’t put strappy leaves or twigs or long grass in there, as they tend to tangle up into a ball and don’t break down very quickly. Chopped up or shredded, though, they do fine. I also get the waste coffee grounds from our coffee machine at work – these are high in nitrogen and excellent for the compost (plus it’s diverting them from the waste stream). Paper from the office shredder is a great carbon source, too.
It’s usually a good idea to add a bit of lime, blood and bone, and a shovel or two of fresh compost to seed the bacteria and micro-organisms. Then give the lot a good watering and seal the lid.
Every morning and evening, I roll the compost barrel around the yard a bit to mix up the contents, and add a little water if it’s getting too dry. It just sits in the sun all day. For the first week or so, the compost gets really hot – so much so that it often steams when you open it. This is great, as it kills off any seeds and pest eggs that happen to be in there.
The compost only takes a month or two to mature, depending upon the materials you started with. If you don’t get the carbon/nitrogen balance right, don’t keep it moist, don’t mix it up regularly, or don’t start with well-chopped ingredients it will take somewhat longer.
The thing I like most about the DIY tumbling compost bin is its portability. You roll it to where your ingredients are when filling it, and once it’s done you roll it to where you want to empty it and just tip it up.
I’m now busily trying to make as much rich compost as I can over the winter, so I can top up all the garden beds and be ready for spring. I’ve been using this compost barrel for about 8 years now (yes, the photo to the right is that old!), and it’s still going strong. I bet if I’d bought one of those $300 commercial tumbling compost bins it’d be broken by now!
One thing to note – if you’re going to use a drum or barrel to make compost like this, find out what it has been used for previously. Mine is an old olive barrel that had also been used to store horse feed. You definitely don’t want to use one that has been used to store chemicals, oil, or some other nasty substance.
**Update:** An Illawarra supplier of these types of barrels is [Drum Master](http://green-change.com/2009/06/02/drum-master-illawarra-drum-supplier/).