How to Mix a Compost Bin With an Auger and a Drill
Turning compost in a plastic bin means a fork that won't reach the bottom. Composters have a shortcut, and half of it is already in the shed.
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Someone with a 300-litre plastic bin asked r/composting in 2024 whether an auger would turn it in place. They had no room for a second pile and no wish to move all the compost around. The next September, somebody else posted a video of a long garden auger spinning in a cordless drill, and said they were very happy with it.
The replies to both add up to the same answer, with conditions attached. If your bin is too tall or too tight for a fork and there's a cordless drill in the house, a bulb-planting auger bit does the turning. The bit is the cheap part.
Which auger bit for compost?
The replies' search term for it is bulb drill. The bits sold for planting bulbs are a steel spiral on a shank that goes in the drill chuck. One person in the 300-litre thread uses a bulb planter auger from a home-improvement store, and warns that the kind made for mixing liquids won't work too well.
One composter got on fine with exactly that, under the title It's not dumb if it works. They compost in a metal trash can with holes drilled in the bottom, and the stuff at the bottom was tough to turn with a fork. On a hunch they bought a paint-mixing bit, and a couple of minutes later it was mixed all the way through.
They'd have preferred an auger but couldn't find one locally. Someone who did buy the garden auger for compost says it works about as well as the mixer sounds like it does.
The auger has one thing the mixer hasn't, which is that the spiral lifts material. The advice from the 300-litre thread is to go slow going in and let the flights pull the crud up the hole.
Size is the other choice. The same reply says you can find them as long as a metre. The person with the video searched for a garden auger and picked the biggest they could find, and another owner's is 20 to 24 inches. A small urban farmer's is 3 inches across.
One reply looked at the video and worried the bit was short enough to fill the drill motor with debris. The answer was that garden augers are pretty long. A long bulb-planting auger on the drill you already own is the shape they're all describing. The Yard Butler Roto Digger is one.
How to turn compost in a plastic bin with it
The top advice in the video thread comes from someone who's used one for a long time.
Pull it 2/3 out, just enough that you can move it side-to-side, move it horizontally, then push back in. Stab over and over like that. You'll get a much better mixing rather than distinct holes.
u/Optimoprimo, in r/composting
The urban farmer with the 3-inch bit stirs their compost with it all the time, and says it takes two hands and five minutes.
One person in the video thread adds browns to the holes afterwards, which is a neat use for them.
What bites back
Four things, each with a fix.
- A snag. A bit that bites a rock or a tangle stops turning, and then the drill body turns instead. One owner in the video thread had that happen in rocky soil rather than compost, and it hurt their arm and wrist. The reply under it has the fix: set the clutch to a lower number before the first hole, so the drill disengages when the bit stops instead of twisting your wrist. Then don't go full speed, and brace the bottom of the drill against a leg.
- The bin wall. Keep the auger off the side of an enclosed bin. One owner who loves it for turning says to watch for it catching the wall, especially when you're holding tight and working fast at random angles, because it could mess your hand up for weeks.
- Fresh compost. One composter in the 300-litre thread found an auger didn't work well when the compost was new, because weeds and hay wrapped around it. Once the pile was more mature and had been turned once, it worked well, so give a new pile one turn with a fork before the auger goes in. The thread starter figured theirs would be fine, since it's mostly kitchen scraps and whatever comes out of the garden shredder.
- The drill. The person who gave the stab technique above says in a later thread that a small battery drill is the wrong tool for it. Attaching an auger to one is a good way to ruin it, and they'd use a corded hammer drill. Nobody in these threads reports one dying, though. Someone who runs theirs in a tumbler uses short bursts rather than prolonged power, and says the drill's been fine so far.
Is a drill auger better than a compost aerator?
The tools sold for the job are hand-crank corkscrews, and the hand-crank people are happy too. The person who started a 2026 thread titled This tool! calls theirs the best compost purchase they've made. It comes in handy for their narrow, taller bins, while a fork does the bigger piles.
Another fan says it's excellent for a tall, narrow bin like a garbage can with holes in the bottom. A pitchfork can't get the right leverage down there.
The person behind the stab technique disagrees. They never found the hand crank more useful than a pitchfork and a good pair of boots, and say the joint strain of cranking it is no better than turning with a fork. Their answer for efficiency is the drill auger.
They also say the hand tool doesn't slide through something solid like a chunk of cardboard. Someone with the same tool and a bin of kitchen scraps and machine-shredded cardboard never had that problem.
Pick by what's in the shed. With a drill already there, the auger bit is practically no cost. Without one, the hand crank is the simpler buy.
Do you have to turn compost in a bin at all?
The video thread got onto worms. One question under it was whether the auger would destroy the hundreds of worms and grubs in a pile. The poster's own answer was "Spin, don't flip!", plus a bet that the worms would bounce back.
The top comment comes from someone who used a drywall mud spinner until they started seeing worms, then stopped and just kept adding. The bottom of their pile is now more worms than soil.
A 2022 thread about an auger in a frozen leaf pile has the composting answer: a pile full of worms shouldn't be turned or aerated at all. Turning is for hot piles decomposing bacterially, which aren't hospitable to worms anyway.
From the other direction, one experienced composter looked at the video and said a few auger holes isn't enough turning for a hot pile. A hot pile wants the whole thing turned on itself two or three times a week for a month.
If your bin is full of worms, leave it alone. The auger is for the composter in between: a bin that wants turning, that won't tip, and a back that would rather not.
Buy the bit, not a new tool, if there's a drill in the house already, whether that's the Roto Digger or any long bulb auger like it. Set the clutch low before the first hole, pull the auger two-thirds out and stab rather than drill, and keep it off the bin wall. A new pile full of weeds and hay gets one turn with the fork first. After that, the threads say, the auger has something it can work with.
