18-Day Compost – the Appliance of Science

Composting puts carbon back
where it belongs
– in our soils!

You may have got beyond the ‘heave it in and hope’ stage of composting, but the average heap or bin still involves a lot of trial and error. This 18-day compost system takes the guesswork out of your heap and turbo-charges the whole process. But, it does require consistent effort for two weeks and careful monitoring to work properly.

Here’s how it was described to LeafTurner by Geoff Lawton, head of the Permaculture Research Institute of Australia. As part of Geoff’s academic research into the usefulness of this approach he has successfully composted the discarded bodies of a kangaroo, and even a penguin (both of which had died of natural causes). But it is not recommended you try that at home!

You will need:

  • a long handled fork
  • a rake
  • a minimum of 1m³ of semi-shaded floor space and room to work around it
  • a water supply
  • old clothes
  • enough compostable material to create a pile 1.5m high. One third of this should be manure (animal dung – horse or cow is good) and two-thirds carbon rich materials (also known as ‘browns’), which can include: ashes, wood, cardboard, corn stalks, fruit waste, leaves, newspaper, peanut shells, pine needles, sawdust and straw

Building and turning

The magic of muck – a compost pile gives
evidence of the heat-producing action of
bacteria breaking down organic matter

Day 1: Shred the carbon material to pieces no bigger than 5cm, about the size of your thumb, and crush them so they are as fibrous as possible. This offers more surface area for the composting process.

Saturate the pile with water as you mix the manure and the carbon materials together.Once this is done, cover it if it is rainy, to avoid too much water getting into your pile.

Day 4: Turn the pile upside down and inside out (this should take about 20 minutes). Then repeat this process every two days, adding water as necessary.

Getting the correct moisture content

This is crucial. Test this each time you turn the heap by picking up two handfuls of compost and squeezing them together. If you see water pushing to the surface, or a single drop comes out, it is fine. If no water is seen, the pile is too dry – add water as you mix. If two drops or more come out, the pile is too wet. This is a problem and will slow compost production by at least two days. To remedy this, ‘fluff’ the pile with a fork and dig a chimney-type hole through the centre to let more air in (force in an implement handle or pole and move it about to widen a little).

Getting the right temperature

By Day 8 your heap should be between 55-65º, which is too hot to keep your hand in.

If you see white powder forming in the heap, it is too hot: do not compact the heap, ‘fluff’ it to allow more air to circulate add sawdust.

If you are successful you should end up with a nice smelling, warm, dark brown compost which can be sieved and used for potting.



  1. Hmmmmm. I feel from experience that composting is one of those things that we master with time, and I can`t say I`ve mastered it yet. The information I would most appreciate from the people in the know is: MISTAKES THAT THEY HAVE MADE. Because there are lots of little errors we can make. The basic, how to`s are simple to understand, and this information is easy to come bye, but its the details that I struggle with. I can make decent compost, but I feel its not the stuff of teas. Let me know how you`ve ucked up.

  2. I’m halfway through the 18-day process–using green matter instead of manure for nitrogen. All is going well except that I see a fair amount of the white powder. Does anyone know exactly what that is? I’ve heard crystalized nitrogen, ash, and mycellium. Would also like to know what conditions are causing it–too wet? too much nitrogen?
    too compacted?

  3. Ive noticed the white powder appears if my compost is too dry and compacted. In Australia at least I’ve tried to keep my compost heap moist by giving it a good soak and turning it over every few days. If it looks like its drying out – I give it a good soak with the hose. Lack of moisture is probably one of the chief reasons (I’d guess) why most compost heaps fail. The bugs and organisms need moisture to survive and do their work. When my chickens run to my compost bins and scratch around the base – I know the system is working.

  4. This compost batch is wet (if anything, it could be too wet but hopefully not). I’ve turned it frequently but it does compact a little between turnings. I’m more inclined to think it’s a function of overheating…

    1. You’re right. The white powder is the remnants or “ash” if you like of nitrogen burning off because your compost pile is too high. Add some carbon and turn the pile to reduce the heat. You can also mulch the pile if there’s too much sun on it but if you’re turning it every other day you’ll have to scrape it off first and tolerate a bit of undigested mulch in the compost.

  5. If you want PROPER compost you have to have the correct c & n ratio. the correct c/n ratio is 1 part very very fine woodchips/sawdust, 1 part green matter such as lawn clipings (excellent heat source) and 3 parts manure such as horse, cow, although you can use other manure such as sheep you will get the best compost if you use horse or cow poo.
    You definately need to measure these items accurately either with a bucket or a wheelbarrow. start off your heap on soil and put each layer as described above, add a light sprinkle with the hose as you finish each layer DONT put too much water on it.after you’ve done the 1st layer put an agi pipe (1 that has slits in the side for air) in the middle of the heap, continue to build all your layers around that pipe, this serves to aerate the heap.

    The higher you build the heap the better the compost will heat up and break down.

    The white matter you will see after a couple of weeks in the heap IS GOOD MICROBIAL MATTER, so dont be alarmed if you dont have this happening your compost heap is not breaking down, a good compost heap which has been built (measured) to the above requirements will break down in around 8 to 9 weeks if it is turned each week, and not allowed to get to wet. You should also see lots of worms within the 2nd week, this means also that the compost is breaking down. When there is no sign of any solid content such as poo or fine wood chips/sawdust your compost is ready. You must not be able to see or distinguish any part of the original materials you put in your heap. Good Composting and BE PATIENT

  6. hello sir
    i would like to know about microorganisms of compost. can you help me??? sir i isolated few but to know about more…

    waiting for your reply

    Neelam Nazir

  7. Neelam – you should go to Dr. Elaine Ingham’s site and read the Soil Foodweb approach. It begins to describe the microbial ecology of compost and soil. By working with microbes and adjusting the compost pile C:N ratio you can produce “designer” composts (bacterial dominance VS fungl dominance) for various soil and plant combinations. A key to making any compost is to keep it aerobic (Oxygen rich). Anaerobic (low Oxygen) microbes produce alcohols, phenols and turpenes (all bad for plants), burn off nutrients (like Nitrogen as Ammonia NH3) as smelly gases, and, if you put this anaerobic “compost” on your soil, introduce “bad” microbes to compete with your soil’s good microbes. Knowing the microbial makeup of your compost is key to understanding whether your compost is good or bad for the soil and plants you want to grow. For example, the discussion above about white matter in a compile may be not be good. It depends on the soil and plant combination you want to achieve. Often, white matter in a pile is Actinobacteria. Actinobacteria used to be classified as Fungi but have recently (through DNA testing) been classified as Bacteria. Actinobacteria dominated compost is great if you have a Fungi dominated soil (near an established temperate forest say) and you want to grow Brassicaceae (broccoli, cabbage, radish or cauliflower) in that soil. The Actinobacteria (white matter and fuzz) in the compost will inoculate your Fungi dominated soil moving it towards a Actiobacteria dominated soil that the Brassicaceae loves. However, if you want to grow fruit trees, Actiobacteria in your compost should be strictly avoided. Fruit trees love Fungo dominated soil particularly with endo & ecto mychorrizal fungi (depending on the trees as to whether endo or ecto). Anyhow, take a look at Dr. Ingham’s approach above and it will get you on your way.

  8. Compost is not a mystery, it once was a talent gained by experience, now it is a science, think of compost as a living organism as “good compost” is more than 50% living organisms. Compost for “compost tea” is not anaerobic and is not dominated by actinobacteria.

    In my experience (working commercially with compost and compost tea), it is difficult to make fungal dominated compost in 18 days, even with proper monitoring and turning, the reason for this is that bacteria dominate during the initial process and once the simple foods are broken down and ingested by the bacteria, it then takes time for the fungi to colonize and establish. I find that too much turning disturbs the establishment of fungi, if you are going to make “18 day” compost, it would be good to add some carbohydrate(oat flour) to the pile at day 18 and leave the pile for an additional 2 weeks without turning to allow time for the fungi to establish. I find that it takes me about 8 weeks to make a good fungal compost by hand (I turn when it is about 65C using a 36″ compost temp probe).

    I know several people that make “quick compost” and that seems fine for vegi gardens and is great for breaking down waste in a hurry when needed, I have never seen a ‘Quick compost” have the adequate diversity for making good compost tea.

    Be very careful with anything anaerobic (looks wet, smells bad), it is anaerobic if it is dominated by actino, one of the major issues is that anaerobic bacteria love to eat beneficial fungi, when a compost tea goes anaerobic and you examine it under a microscope, it is literally covered with anaerobic bacteria (if you would like a photo of this email [email protected]), within 24 hours after the tea is made, there are no fungi left in the sample (this is also a concern with manure teas that are often anaerobic because of a lot of misunderstanding). Beneficial fungi are responsible for soil structure, soil pH, ambient moisture, and for the mineralization of the soil, the most difficult thing to re-establish in degraded soils is beneficial fungi, so be careful.

    Compost for making “inoculum” for compost tea, is an aerobic process, we use about 45% carbon (not too fine half of the C as wood chips works well), about 35% “green waste and the balance manure, legumes, lucerne, etc. One of the principles that I have discovered is that “diversity of materials supports diversity of microbes”. The key to “inoculum” compost for compost tea is to get a massive diversity of beneficial microbes. And as Dr. Elaine Ingham (Queen of the science of compost tea) might say, we are not making “decomposed organic matter” we are making aerobic, thermal compost, it must be monitored by temperature and by moisture. Once the compost gets to about 65C we begin to get lower O2 conditions and we begin to lose diversity of beneficial microbes, we also begin to gas off valuable nutrients.

    When first building a compost pile, we usually place about 150 mm of wood-chips on the ground first and the build up the compost pile on top of this, this will help to ensure that the diffusion of O2 is adequate during the process as O2 can diffuse not just through the sides of the pile but from the bottom as well.

    Compost tea is also a highly misunderstood process, it must be aerobic, “compost tea brewers” are powered by air pumps, not by water pumps and it is not made successfully in water that is not aerated.
    The importance of Actively Aerated Compost Tea” ( is that is is aerated with an air pump, the air is sent to the bottom of the container and the water is moving enough to look like the water is boiling. Compost tea requires an “extraction” process, we must ensure that we are washing the microbes off the organic matter of the compost and have them “free floating” in the solution so that they are available to be activated and multiply in during the brewing process.

  9. I really appreciate the information provided above, especially the knowledge of chemistry and biology in which I am woefully inadequate.
    I live in Adelaide and have been composting for 20 years plus. Sometimes I make excellent compost and sometimes I end up with a stagnating pile (after the initial tremendous heat in the first three or four days). I find that I have to distribute the stagnated pile amongst new batches. I suspect that this might be a very naughty thing to do but I have to do something to finish it off.
    I also suspect that the wonderful rich, crumbly, moist, dark compost we see in books and television shows which looks like commercial seed raising mix, might, in fact, be commercial seed raising mix.
    After scores of batches, I have yet to find that all elements are unrecognizable at the end, even after leaving batches to go anearobic for a month or two after the initial aerobic cycle with frequent turning. Similarly, whilst I use a petrol powered chipper to smash things as small as possible, it is always very twiggy. I have to sieve off finings for the same effect as the commercial pictures of compost and this is not practical for the entirety.
    My biggest issue is water. To eliminate vermin, I have to use bins with galvanised wire mesh bottoms (10 mm by 10 mm) and I think this stops me having the recommended bulk of 1 cubic metre. I never add moisture as the kitchen scraps are just so wet, as are the lawn clippings. I mulch phone books, straw and woody parts of shrubs to kind of add more “dry brown” but it is never enough.
    I know it is again naughty but the reality for city / metropolitan people is that you do have to keep adding to a pile daily. There is just no way to store kitchen waste long enough to start a single pile periodically. No matter what the books say, it does start to smell even though you have a lid on a bin.
    I have tried to squeeze the moisture from kitchen waste prior to adding it to the bins but they just get too wet.
    I have even tried to drain off the evaporating water collecting on the lids of the bins with zero success.
    I think that I need a ton of (dry)animal poo periodically but this defeats the purpose of trying to have a circulating nutrient system with little external input apart from the kitchen scraps which often contain shop bought material.
    Don’t get me wrong. Even if a composting effort is only half successful, we have still added nutrient to and improved soil and we have reduced the “crime” of throwing nutrient into land fill.
    I will just try to keep having a go, adding as many different ingredients as I can lay my hands on and keep trying until, by trial and error, I get it right.
    One tip I can give is to even out your input by storing dry browns if you can. For example in Autumn, I have a wonderful supply of fallen leaves and whenever I cut the lawn, I have three barrow loads of grass. In order to use them and stop them from clogging the pile, I have to add dry chipped plant material, shredded cardboard and dried grass I have laid out in Summer. This does take a lot of space in my garden shed however and is a real fire risk in 40+ degree Summers.
    Oh, another thing, hedge clippings are great for heat and aeration and the clippings from lavender are brilliant for making it burn like a fire and smell fantastic!

  10. Hello ‘Rob the Rat’,

    Great to hear that other people have been making compost for 20 years or more! When you talk about having ‘stagnating piles’ this to me means that they are smelly and hence anaerobic. The thing that you need to look out for when you mix aerobic with anaerobic compost is that anaerobic bacteria eat highly beneficial aerobic fungi which is the hardest thing to actually grow properly I compost and the hardest thing to re-establish in soils. When you have a ‘stagnating pile’ what I would do is mix it in with some larger particle material such as wood chips which would get the air back into it and then use it after a couple of weeks to make a new compost pile. A compost pile should not go anaerobic simply because it is hot outside, it goes anaerobic because it cannot diffuse oxygen because it is either too wet or the particles that you used initially were too small. It can easily go anaerobic if it is covered with plastic during the heat so if you are going to cover it with something to keep the moisture in make sure that there is a 200mm air space between the plastic and the compost pile and that the plastic is not held down so tightly so that air cannot get under it. Remember, we are making inoculum compost which is aerobic and more than 50% living organisms. This is not just ‘decomposed organic matter’ (which is OK as a garden food but does not revitalise degraded soils).

    I have never been able to successfully make quality aerobic compost in a plastic bin. I suggest that you make a circle out of fine wire mesh and use that as your compost container. That way the oxygen will be able to diffuse into the pile and it will not overheat. As temperature goes up the ability for air or water to hold oxygen drops. If your compost stinks it is not beneficial to your plants as it is anaerobic. Even if it gives you plant growth it is at a cost of soil health.

    Feel free to send me a photo of your compost and I’ll send you a photo of what we make [email protected]. Also see

    Regards, Paul Taylor

  11. Thank you Paul for taking time in replying and your considered response to my problem.
    I am heartily cheered to read that you have not made quality aerobic compost in a plastic bin. Clearly my problem is that I am just not getting the volume large enough to generate the heat and as you say, oxygen is not available. I suspect that this is because the available oxygen in a recently established or turned bin is quickly consumed by the bacteria and then they slow or shut down due to asphyxiation.
    I am really pleased to hear an experienced and successful composter state this because I read a great many books and websites on this subject and they are quite flippant about how easy composting is in plastic bins.
    I only have one commercial plastic bin as the rest are large plastic pickle barrels with the bases cut off with an angle grinder. I selected these because they were cheap and robust, but also because they were larger than shop-bought bins. They are obviously still too small however and keep out the oxygen.
    I will try the wire mesh cage idea, if I can work out a practical base and removable top (because I imagine I will still have to turn it).
    I have no reason to believe that I am attracting rats or mice by composting, however I am very conscious of being able to prove to neighbours that rats cannot get into the bin if they should ever complain. (The neighbours, not the rats)
    I know that material is very quickly de-natured in a hot pile anyway but I suppose I could continue putting potentially attractive kitchen waste into my rat proof wired plastic bin until it is completely unrecognisable before adding it to the wire cage containing the lawn clippings which give me such grief in the plastic bins.
    I feel confident that I can supply enough dry browns to compost the kitchen waste in the bins whilst allowing the wet grass clippings and sundry prunings to get highly oxygenated and “dry out” in the wire cage.
    It’s a shame because I believe that the pile would benefit from the inclusion of a range of materials, especially high nitrogen kitchen waste and as you explained, it’s not good to add anearobic material to an aerobic pile. I would love to be on a small holding and not have to worry about neighbours, however I have to deal with this as the great majority of people live in cities and composting is just as necessary in built environs.
    I wish I could keep worms because this would solve my kitchen wast problem, but I was a dismal failure when the Summer temperatures became outrageous and it was not fair to the little brutes. They all nicked off.

    Thanks again for your interest and response. I will send you a photo when the current batch is finished.

  12. What is inexpensive to build or buy, runs on human power, shreds small branches, cardboard, paper, food waste, and leaves? I don’t know, but if you see one, grab it for me!

  13. Ten days ago I made ​​a compost pile of weeds, compost and a little fresh broccoli, which finished flowering.
    Stink like rotten sauerkraut…..
    So if you want to put Cabbages, kill the darn thing first.

  14. I found that using a childs 4 ft diameter plastic pool is economical and works well for both the top and bottom of a wiremesh cylinder (also about 4 ft high) for composting.that seems to be a good bulk for heating up (about 50% of the sides are also lined by black trashbag plastic which allows better air and moisture control.)

  15. I really hope it is not too late to leave a comment/questions on this post. I hope somebody else (but with experience) has the patience to read all the way down to the very last comment.
    So here’s my problem: I started making a Berkeley Compost mid-November. There were tons of dried brittle leaves and plenty of green weeds to pull and fresh grass to cut. There are also chickens and pigs on the farm here (both vegetarian) so no problem with the manure either. I built my first pike outside. Mind you I’m up in the Catskills and temperatures out here are not exactly favorable, but I figured I’d go with the Berkeley pile since it is a microbial reaction that happens inside the pile and should not be affected too much by outside conditions. My first pile got up to 80 degrees in the first few days. I was told to move my pile into the hoop house to get better results, plus it was just more convenient for everyone if I put it there (there is sufficient room to turn the pile). I had also not realized the first time building the pile that I should be watering each few layers, so this gave me a chance to turn the pile and water it. I actually made a list of the components in my first pile:
    * Turned up compost
    * Chopped leaves/sawdust/broken up bark/broken sunflower stalks/partially decomposing wood (all leaves very fine/rest – nothing hard or over 2 inches)
    * Grass clippings – fine
    * Weeds – mass
    * Activator #1 – Chicken manure (stuffed, big Ziploc bag)
    * Chopped leaves/sawdust/broken up bark/broken sunflower stalks/partially decomposing wood (all leaves very fine/rest – nothing hard or over 2 inches)
    * Grass clippings – fine
    * Weeds – mass
    * Activator #2 – Pig manure (started using from 5 gallon bucket – pure liquid shit)
    * Chopped leaves/sawdust/broken up bark/broken sunflower stalks/partially decomposing wood (all leaves very fine/rest – nothing hard or over 2 inches)
    * Grass clippings – fine
    * Weeds – mass / comfrey and nettles (plants)
    * Activator #3 – Ash from old wood fire
    * Old inactive compost
    * Chopped leaves/sawdust/broken up bark/broken sunflower stalks/partially decomposing wood (all leaves very fine/rest – nothing hard or over 2 inches)
    * Grass clippings – fine
    * Weeds – mass
    * Activator #4 – Pig manure
    * Straw/wood mulch
    * Chopped leaves/sawdust/broken up bark/broken sunflower stalks/partially decomposing wood (all leaves very fine/rest – nothing hard or over 2 inches)
    * Grass clippings – not as fine
    * Weeds – mass
    * Two dead rats – one very big one very small – opposite sides of pile – a little
    * Activator #5 – Comfrey and Nettles stalks – two months soaked in water
    * Chopped leaves/sawdust/broken up bark/broken sunflower stalks/partially decomposing wood (all leaves very fine/rest – nothing hard or over 2 inches)
    * Grass clippings and moss
    * Weeds – mass
    * Activator #6 – Pig manure (finished 5 gallon bucket) & a bit more wood ash
    * Weeds / wood mulch / leftover anything from piles / comfrey and nettles (plants)
    * Old inactive compost
    I know it was probably a bit overboard but I really wanted it to work. When I put the pile in the hoop house I added some 0f the same ingredients plus some coffee grinds to the mix. That pile got up to about 110 F in about four days, before it started to drop to 105 the next (5th) day. I probably should have left it alone but I turned it. Since then I’ve tried to fix it with different materials: kelp powder, roadkill, lots of chicken manure, chipped sunflower stalks, cut up cardboard, newspapers, more coffee grinds from starbucks, hay, more leaves (ran over them with the electric lawnmower), but it’s all of no use. I can’t get back to that temperature, and it’s only getting worse. My pile is turning into essentially what looks like a pile of mud and hay. I don’t think the problem is the freezing weather or snow because it did work up to a point; however, the snow is really the problem now because it covered most of the things I would use to build another pile: dried leaves are gone; grass is covered; weeds are covered; muck and manure is covered. I do have some access to more chicken manure but I don’t really know how much of that is too much. I also thought of using some compost starter, but I don’t know if adding that to a muddy pile will be of any use now. I’ll probably just bury it deep in mulch and let it sit until next year. Berkeley Compost fail :( but hey gotta start somewhere I guess.

    1. Berkeley Compost Fail,

      Sorry for such a late reply. If it doesn’t help you, it might help someone else that comes along.

      I’ve been making compost for about a decade. Over this winter I made about 180 yards of well finished compost in 90 days in Utah: elevation 4,500 feet, USDA zone 6a.

      I don’t know precisely why your pile started loosing temperature, but from the description, here are my suggestions in descending order of most likely to less likely:

      1- Check water content. If your pile looks like a muddy mess, it is likely too wet. As suggested in the article above, take a handful and squeeze it. If you have any water run out, it’s too wet.
      2- Adjust your pile height/size. In my experience, your pile must be at least 3 feet wide and tall, or there will not be enough mass to get and keep things going. If you only have a small amount of material to work with and cannot get a good size pile (at least 3 feet in diameter at the middle), you will have use wire mesh or something like that to hold the pile into a column in order to get the mass necessary to start and keep the biological fire burning.
      3- Too much N, too little C. From your description, you have quite a bit of nitrogen in that pile. It might be too much. Though some here have suggested having a higher ratio of N to C, I prefer a mix like the one this article suggests: 1/3 N to 2/3 C. If your pile tends to run wet and/or anaerobic, you might find that shifting toward more C can help. Besides the C can help absorb more water and increase oxygen.
      4- Ash. I don’t like adding ash to my pile. I have found that charcoal works fine, but ash tends to kill my piles, so I avoid it.
      5- Manure. Not all manures are made equally. Chicken manure is hotter (more N) than other manures, so when mixing it into my piles I use 1/4 of the mount that I would use with horse manure. If you have too much N, do not despair, add more C. If I have to error on a side, I try to error a little on the C side of the equation, because that side is more forgiving than the N side.

      Happy composting!

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