Tumbler Composting

compost tumbler

Make composting waterwise, quick, and easy, with a compost tumbler!

Composting using tumblers is far easier than traditional pile-building techniques, and can be done entirely separately, or in conjunction with pile-building to make large amounts of compost.

Benefits:

  • Quick
  • Easy
  • Tidy
  • Waterwise

Materials:

  • 1 x Compost Tumbler
  • 1 x Sheet of cardboard
  • All food scraps
  • Weeds and yard prunings
  • Leaves
  • Newspapers and plain cardboard
  • A bit of soil

Jump to:

What is a Compost Tumbler?
Homemade Designs
Design #1 – ‘on the ground’
Design #2 – ‘end over end’
Design #3 – ‘barrel-roll’
Filling a Compost Tumbler
When to Tumble a Compost Tumbler
Emptying a Compost Tumbler
Using Compost Tumblers With Compost Bins
FAQ
Why compost in a compost tumbler?
What can I compost in my compost tumbler?
How often should I tumble my compost tumbler?
Do I need to water my compost tumbler?
When will the compost be ready?
How much compost will I get from my compost tumbler?
Should I keep adding to my compost tumbler?
Why isn’t my compost heating up?
Related Articles
Cardboard Compost Bins
Human Waste Composting
Bokashi

 
Composting - Tumbler Composting - Compost Tumbler 01.jpg

Two compost tumblers used alternately to manage more waste.

What is a Compost Tumbler?

A compost tumbler is a compost bin designed to be rotated, so that materials inside are remixed for aeration and faster composting. Most are supported off the ground by a frame, so they can be situated on sealed pavement. The same materials that could be added to a regular compost pile can be added to a compost tumbler, and often the tumbler is able to heat and break down the material faster and with far less water than a pile. The result is a rich, uniform fertiliser for the plants in your garden. Compost tumblers are usually more expensive than regular compost bins but the utility they offer makes them well worth considering.

Homemade Designs

I have seen a few different designs innovative people have implemented to get their compost tumbling. All will do the job just as well as a purchased one.

  • Design #1 – ‘on the ground’

Any large cylindrical container can rather instantly become a compost tumbler. Simply fill it up with materials, close the lid, and roll it around on the ground! The best container for this is a plastic 200L barrel which has a removable top – they are easiest to fill and easiest to empty.

  • Design #2 – ‘end over end’

Take a plastic 200L barrel with a removable top, and run an axel through its side. Build a frame to support it off the ground and voila! Materials go in the top, the lid seals and the barrel is flipped end over end. The only trouble with these types is they can become difficult to flip if the contents sink to one end.

  • Design #3 – ‘barrel-roll’

Take a 200L barrel, run an axel through the top and bottom, and stand it on a frame, like a pig on a spit. Cut a hatch in the side as wide as you can without compromising the strength of the barrel, and fix the flap back on with hinges and a lock. You can either roll it on the axel, or fix the barrel to the axel and add a crank.

Filling a Compost Tumbler

All kitchen scraps, egg shells, weeds and prunings, grass clippings, leaves, newspapers and plain cardboard can be added to a compost tumbler, and a mix of all these ingredients plus a bit of soil makes for a good recipe.

With one end closed, I fill my tumbler with all the compostable materials I’ve collected over one week. Kitchen scraps have been preserved in buckets with bokashi (no bad smells), egg shells have been left to dry out, newspapers and plain cardboard collected in a separate bin, and weeds and prunings collected in a bucket.

My neighbour is a lawn-mower man by trade, and he’s allowed me to take as much grass clippings as I wish for my garden. It’s not a necessary ingredient in a compost tumbler, but I use a lot of it because I can. It allows the bin to heat up very quickly and very hot.

I half-fill the compost tumbler with grass clippings, shred newspapers and cardboard before adding them, crush egg shells and add the carton as well, any weeds and prunings go in, and kitchen scraps are emptied in along with water from rinsing the buckets. I finish filling the bin with grass clippings then close the lid and tumble the bin until the materials are thoroughly mixed.

When to Tumble a Compost Tumbler

A good mix of materials will heat up as they begin to break down. This should happen within the first week after filling a compost tumbler. It is not necessary to tumble during this phase, and it may in fact cause the pile to cool down, which is undesirable. Allow the hot phase to persist, and when you notice a drop in temperature this is the time to tumble.

After tumbling the first time, the material should heat up again, though its unlikely it will reach as high a temperature as during the first phase. Once again, wait until the temperature drops before tumbling again.

After the second tumble, the material may not heat up again, and will most likely remain warm. This means it is still active, but active with a different group of bacteria and fungi to the first phase. The material breaks down slower in this phase, and oxygen should penetrate as the bacteria and fungi require, which means you shouldn’t have to tumble again. From now until the compost is finished, only tumble if you detect a bad smell.

A compost thermometer is a great tool for monitoring the activity of materials in a compost tumbler. I’ve used one many times to determine the right time to tumble, and a good time to empty the bin.

Emptying a Compost Tumbler

To empty a compost tumbler, the best way is to lay a sheet of strong cardboard down underneath the bin, open one lid and tip the compost out. Pick up the cardboard and tip the compost into a wheelbarrow. It takes me a few tips to empty my compost tumblers. Be sure only to tip out what you can easily pick up and carry.

Using Compost Tumblers With Compost Bins

I’ve developed a system of composting which maximises the benefits of both compost tumblers and stationary bins. I’m able to empty and refill my tumbler as often as once per week, which allows me to take in a lot of materials and make a lot of compost.

Over the course of a week, I collect about 20L of vegetable scraps, at least one newspaper, some plain cardboard, and if I go for a walk at the beach I pick up a bucket load of seaweed and cuttlebone. My neighbour is a lawn-mower man by trade, and I grab a bag of grass clippings each time I’m ready to do composting.

I add all the materials to my tumbler, tumble it to mix it up, and let it cook throughout the week, tumbling only when the material begins to cool. By the end of the week, the material is brown and has shrunk to less than half the original volume. It has finished passing through the thermophilic phase of composting, and can now be effectively composted in a larger bin.

I remove the covering from my cardboard compost bin, then dig a hole in the centre of the pile – pulling the previously added material to the sides. I empty the contents of my tumbler, using a sheet of strong cardboard, and dump it in the centre of the pile. Finally I cover the pile and go on to refill my tumbler with fresh material.

The pile in the cardboard compost bin is warm, and the material slowly breaks down in a mesophilic phase of composting. The bacteria and fungi that are active during this phase are not so desperate for oxygen, and so the pile does not need to be rotated. Also, the environment is perfect for earthworms, and I find more and more earthworms living in my pile.

It takes me about 3 months to fill a cardboard compost bin with partially-cured compost, and about another 3 months before it’s ready for use. I usually have two cardboard compost bins in use – one ageing, the other active.

Using this method, I’m able to produce about 1 cubic metre of cured compost every 3 months, which is enough to cover all of my vegetable beds generously.

Frequently Asked Questions

Why compost in a compost tumbler?

Traditional methods of composting usually involve rotating/turning a pile of built material, which is a back-breaking task. Compost tumblers make this job a hundred times easier.
Consider using a compost tumbler if:

  • You don’t have a space in your garden for a compost pile. Tumblers can be situated on paving or sealed concrete without making a mess.
  • Rats are being attracted to your compost pile. Tumblers are rat-proof.
  • You want to produce a lot of compost fast (like me!). Use your tumbler as I do, in conjunction with cardboard compost bins or other stationary bin, for a fast turn-over of compost.

What can I compost in my compost tumbler?

All organic materials can be composted, one way or another, but some materials require more time or more heat to break down properly.

  • In general, your compost tumbler can take all kitchen scraps, egg shells, weeds and prunings, grass clippings, leaves, newspapers and plain cardboard.
  • If you’re certain your materials will heat above 50degC (thermophilic temperatures), you can also add meat and dairy waste, but add it after you’ve mixed the normal ingredients, then bury the meat and dairy materials in the centre to ensure they are heated and broken down.
  • You can add branches or wood chips, but these take a long time to break down and will not be finished when everything else is ready. However, these materials will continue to break down after you’ve applied your compost to your garden.
  • You can also add soil amendments to your compost, even though they will not break down. For example, I’ve added clay, biochar and cuttlebone to my tumblers, so that they are mixed in with my compost when I spread it around my garden. They are also covered and filled with humus and moisture, ready to help my plants and soil grow. I’ve also added leftover chicken manure pellets and super phosphate to my compost tumbler, so that it is not so concentrated when it ends up in my soil.
  • You can also add soil modifiers such as lime and sulphur to your compost tumbler, but these may hinder the composting activity, so it’s best if possible to add the modifiers gradually and directly to your soil.

How often should I tumble my compost tumbler?

  • When it’s first filled, to mix the materials thoroughly.
  • Again, once the initial heat phase begins to cool.
  • A third time, once the second heat phase begins to cool.
  • A fourth time, only if you detect a bad smell.
     

Do I need to water my compost tumbler?

Fruit and vegetable scraps have more than enough moisture in them to break down, as do fresh grass clippings and any other fresh plant material. Newspapers and cardboard might need to be moistened before adding, but consider there might be enough moisture from other materials to dampen them. It is better that your materials are too dry, so you can add a bit of water until it’s damp, than too wet, in which case you will have to tumble every day to avoid bad smells!

When will my compost be ready?

Your compost will be ready when it is dark brown or black and crumbly, cool, and smells earthy. You shouldn’t be able to distinguish any of the original materials, and there shouldn’t be signs of fungus or warmth which suggests it is still active. Even if it’s warm, you can still add it to your soil, but it won’t be ‘plant-ready’ until it has finished breaking down. Allow three months for your tumbler to fully break down a batch.

Should I keep adding to my compost tumbler?

You certainly can add to your compost tumbler, though it is better to batch-fill, to take full advantage of the heat that can be generated. If you add materials gradually, you may not achieve high temperatures, and you will find it more and more difficult to tumble, as the weight of the material becomes concentrated into smaller particles.

How much compost will I get from my compost tumbler?

A nice mix of materials filled into your compost tumbler should reduce to between 1/4 and 1/3 the original volume in finished compost. In my experience, one batch can cover a 5 square meter garden bed a few centimetres thick.

Why isn’t my compost heating up?

The materials in your compost tumbler heat up as bacteria become active. Their activity depends on moisture, air, and a good mix of carbon-rich material and nitrogen-rich material.

  • Newspaper, cardboard, straw and other plant stalks are carbon-rich materials. Bacteria consume this for energy.
  • Leaves, grass-clippings, vegetable scraps and manure are nitrogen-rich materials. Bacteria consume this for protein.
  • Including a variety of carbon-rich and nitrogen-rich material in your compost tumbler ensures bacteria have all they need to create compost.
  • Experiment with different amounts of materials until you find a recipe that suits you.

The ideal moisture conditions in a compost pile is damp, but not sopping wet. If your pile is too wet, add dry shredded cardboard or newspaper and stir it through. Your amended pile will not likely reach thermophilic temperatures, but it should be saved from putrefaction!

Related Articles

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Human Waste Composting

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Bokashi

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12 comments on “Tumbler Composting

  1. Any advice about coffee grounds? We generate a lot of grounds but I think they give my compost pile indigestion. The community garden by the coffee shop seems to have a similar problem.

    • Hey again Drake!

      Coffee grinds are not to be wasted!

      Worms love them; my Dad has three worm farms fed on coffee grinds and part-composted grass clippings and vegies. He uses the urine in his wicking beds, and the castings all around the property, with improvements all round.

      Personally, my coffee grinds go into my biogas digester and produce more flammable gas than anything else I put in there!

      Also, I’ve seen an article on a car that runs entirely on coffee grinds, and can go 60km/h!

      I’ve even heard of grinds being pelletised and sold as fire pellets!

      Good Things

  2. Hi,
    I got rid of my compost tumbler because I never fond that it mixed the contents well enough when it is rotated. Because when it’s full, all the compost does is rotate , it doesn’t tumble, which is what you do when you turn a compost pile. Even when I tried it at 3/4 full, the compost would only rotate in a slab. Perhaps mine was too wet? Maybe it should only be half full? Turning it over doesn’t do any good, it has to mix as it tumbles.
    Wayne

    • Hi Wayne, thanks for your comment. I have to agree that the tumblers dont mix as well as a good pitch fork can, and ive had the same experience when its so full that it just shunts back and forth and doesn’t mix at all. Ive also noticed that whole fruits and potatoes tend to tumble around the outside and collect together at the bottom. Ive even had one tumbler so densely packed at one end that i couldn’t turn it!

      Yes, they do have their drawbacks, but if you get your mix right (i use about 50% grass clippings) and only fill it 3/4, you’ll get everything mixing well enough for thermophilic breakdown, which is the holy grail of composting – it’s hot and quick, and as it cools you can often tumble it and get a second ‘cook’. After this phase, which can be a few weeks after filling, you can transfer the compost to a larger compost bin (for aging), feed it into a worm farm (that’s what i do), or use it to top-dress your garden beds as mulch.

  3. Thanks for this – really useful for those of us new to compost tumbling. I am thinking of putting my partly cooked compost under the banana plants in my garden – apparently they like it rich… Nicole

    • Thank you Nicole. If you’re going to put ‘unfinished’ compost in your garden, don’t dig it into the soil, as the microbial activity might take carbon/nitrogen out of your soil to use for decomposing the compost. Put it around your trees and mulch over the top. In time the earthworms and other organisms will absorb the nutrients into the soil below. Good Luck!

  4. You say it may take up to 3 months before the compost is ready for use? By that time the growing season will be winding down. Is there a way to speed up the process?

    • Hi Allan, good question. Its true there’s a delay with composting, which is why people opt for bins which can be continuously taken from at the bottom while fresh material is still being added to the top, or why some people get themselves a second tumbler. Ive tried both, but have settled for a different system…

      Tumblers are great for their easy mixing and the possibility of reaching thermophilic/hot composting throughout all the material, but after the hot phase it pretty much sits there for weeks or months curing. So after the hot phase, I empty the tumbler into a large worm farm. The worms can chew through partially cured compost, and if you’ve got a decent population they can get through a batch in a few weeks, making it possible for scraps to be garden-ready in a single month. I haven’t been dilligent though, and dont have the population up yet, so im still at around 2 months. There’s all different ways of doing a worm farm. Hope that helps

  5. I put worms from my garden into my black tumbler bin to work on the compost . It’s a roll type with the A-frame legs. The bin sits in the sun. Is it too hot in there for my worms to live?

    • Hi Michelle, glad you asked. It will definitely get too hot if its in the sun, and if you’re doing batch composting, where temperatures increase a lot, you may cook the worms that way too. In the shade, adding occasionally, they should be okay. Its not exactly they’re natural environment, but if you only rotate it a little each week, they should be fine.

    • Hi Glenn, the concern with processing human waste is the potential for pathogens to survive and be passed to other humans. Whatever systems we design must account for the possibility that pathogens may end up in our system, and ensure they cannot survive.
      The best system ive come across, for its simplicity, is Joe Jenkins method, as he outlines in his book ‘the humanure handbook’. Human waste is introduced into the centre of a compost pile, kept covered, and left for a year to ensure pathogens cannot survive. The aim is also to combine kitchen waste and other prunings, not only to simplify waste management, but to achieve high temperatures in the compost, which can eliminate pathogens much faster. This two-prong approach has been trialed in countries where pathogens are common.
      As for tumblers, they have the ability to mix contents thoroughly, and in my experience they make thermophilic composting easier. But human waste dumped in a tumbler and tumbled around is going to leach out of the tumbler, and unless the bin is left for a year, it will be possible for pathogens to survive around the inside surfaces of the bin where temperatures havent killed them. This is not to say its not possible, just that it will take some planning.
      For example, if you dig out a dish shape in the soil below the tumbler, and fill it with straw or another absorbent organic material, this may serve to soak up leachate. Also the tumbler could be fenced off as a ‘phase one’ for your waste, and after temperatures have cooled you could carefully transfer the contents either to a holding bin for a year, or bury it around plants and trees, careful to cover it with mulch and avoid disturbing the area for a year.
      Having said all that, if its just the two of you entirely off grid, then if youre not bringing pathogens into the system, there’ll be no pathogens to safeguard against. If youre having visitors contribute to your system though, take some time to consider safe practice.
      Good luck!

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