Composting Medium

By Carolyn Shearlock © 2015 • all rights reserved

Composting Medium for Composting Head: What are the pros and cons of the various composting mediums for composting heads? What's best?

Okay, we’re installing a composting head – a Nature’s Head to be exact – and know that we can use either sphagnum peat moss or coconut coir as the composting medium.

Assuming that we can easily get both, what are the pros and cons to each? Is there something else you think is even better?

I know that coconut coir is the sustainable choice, but I’m wondering about other factors as well:

  • Cost?
  • Size in relation to how long it lasts?
  • Weight?
  • Ease of using (for example, does one tend to fly around more when you open a new package)?
  • Bug/fly/other critter attraction?
  • Smell?
  • Anything else?

Tips and info greatly appreciated (and I’m sure by TBG readers who are thinking about converting to a composting head, too) – leave your thoughts in the comments below. Comments left on Facebook will also be imported.

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  1. Grefory Pace says:

    Isn’t Coconut Coir just the dried husks of coconuts?
    So it would seem Eco Friendly and available in any tropic or semi tropic area for cheap or free. Plus would be the nuts 🙂
    Wonder how long it would take a coconut to dry???

  2. Our Nature’s Head is brand new, just installed literally, moments before we had guests onboard. It is interesting to note that they preferred the composting head forward, vs the regular pump head aft. We haven’t had much time with it, so we are still in the getting to know it stage. This is what we purchased:

    This brick is extremely compact, and you have to break it up when you add some to the head. So, we figure, this one brick may last, 2 people onboard, about six months. We shall see, so far, no bugs, no smell, easy to use, it’s a winner.

  3. Follow

  4. We also use a Nature’s Head and we have only used the coconut coir. We get the bricks and reconstitute one in a bucket for a day or so and then change out the old stuff and put in the new stuff. Be sure to use warm water. Use what is recommended on the package or a little less so it is a little dry. The brick we have makes 8-9 liters which is just about right. We don’t fill it too full as it makes the waste bag very heavy.

    We are getting a little over a month between change outs because we don’t like trying to haul in the heavy bag in the dingy. We have added more and lasted longer but the bag was very heavy and difficult to haul in the dingy.

    Use have been using Glad 13 gallon tall kitchen bags, extra strong. I would not recommend cheeping out on this. The bag just fits over the square opening allowing you to turn over the container. Tap it a couple of times and then carefully turn it right-side up. Leave the remaining compost in the container. Double bag tying the inner bag then the outer bag and there may still be some smell.

    Last time we purchased the coconut coir we found the best price at a hydroponic garden shop. A lot cheaper than even Amazon. About $2 per brick.

    The bricks stay compressed until warm water is added and store well on the boat. We have had bricks on FatDash for over a year. We use the water from our solar shower.

    Flies will get in unless you put some sort of screen over the intake on the head and one on the exhaust.

    There will be a dirt smell and for a time after the business is done there will be a smell.

    We have heard that peat can have bugs in it and you must go through a extra step to get rid of them.

    I hope this helps.

    • Denali Rose says:

      All good points and suggestions, thanks for posting.

    • Thanks for all the info — I know there’s going to be a learning curve so this helps a lot!

      • A word of caution! The urine container lasts about a day for us, more if we are onshore a lot. We keep a flashlight nearby and shine it on to the container. If you can see the urine in the container above the bottom of the crescent in the front of the holder change it, especially if it is night time.

        We learned the hard way and it is an ugly mess to clean up.

        • Denali Rose says:

          Yes, to the word of caution! We had a family of 6 onboard, with us, a total of 8! I went in the foreward head, and saw “water” on the floor. It was a live and learn experience, hopefully never to be repeated.

  5. we use coconut coir and love it, we like the compressed blocks as it’s so easy to store. i think we have a 2 gallon bucket we fill when we moisten and uncompress, and that will last us a while. much better than peat moss!

  6. When we had our composting head in the colder Pacific Northwest we had trouble getting the waste to compost. Adding an enzyme called Drain Care helped tremendously. By composting faster we no longer had trouble with bugs.

  7. You might want to ask Robin…they had a composting head on The Cat’s Meow and it never ever emitted an order of any kind that I could detect…

  8. coconut coir… hands down.. not because of smell. but it is bug free and also very compact to store… Peat can carry eggs and then you have all those black flies up in your business.

  9. Coconut coir worked best for us. We have used both moss and coir. Coir is easily stored when traveling. We also traveled with Diatomaceous earth, not sure of the size. Only had to use it once. Our composting head is a must have on Last Mango. We also carry an extra urine jug…. You never know when you may need it. We too have a natures head.

  10. We use pine pellets mixed with water to make saw dust.

  11. Have used both. coir in my opinion is easier to use and less messy. Also coir bricks can be purchased at any pet shop that sells reptiles.

  12. Ditto on the coconut coir. We are live aboard and have us d both. The coir seems to dry better. It is compact in storing and lasts longer as a medium.

    The only drawback is the processing time on breaking it up.

  13. Christina says:

    There is a great series in composting toilets, specifically Nature’s Head at Gone with the Wynns. They also discuss coco coir vs peat moss in detail. They’re on an RV, not a boat, but I would imagine a lot of the same issues apply.

  14. I use 2 Coco Tek bricks per mix. Very loamy! like it a lot. I buy it here

    • Following! We’re in our first season with the Airhead that came aboard Sionna. Using peat which is working fine, but its all we know so far. What’s the Diotomacious earth used for?

      • Tom Geren says:

        The DE kills bugs, I’ve heard. It’s cheap at the pool supply store and a little goes a long ways.

        I haven’t tried the Nature’s or Airhead, and there may be some advantage for fulltimers if you really get long times for composting (which I kinda sorta doubt) but for weekenders, the C-Head is all you need.

    • Keith Davie It kills bugs. “Poopy flies” and the maggots . . . as I understand it, you can either use a little all the time or wait and see if you have a problem and then use a larger dose.

  15. Diane Dashevsky says:

    Peat moss is all you need! Usually readily available where ever you might me (can always carry an extra bag “just in case”), Absorbent, no odor, and when you finally have to empty your head, you can simply dump it on a garden! Seriously…you will just have “dirt” with no “potty” odor. My understanding is that the coconut stuff doesn’t last nearly as long. Last winter we got got just shy of 6 mos with daily (and nightly) use before we had to change out the peat moss. Just make sure you put enough in and turn it daily – even if you don’t use it for some reason….

    • Diane Dashevsky says:

      NOTE!! Althought Nature’s Head says you can, we don’t put paper in our head (I have a small covered step-on can next to the head) nd that’s probably why we get so much more usage from a single bag of peat moss.

  16. Peat moss is a diminishing resource, so environmentally, coco coir is the preferred option.

  17. Joie de Vivre says:

    We’ve used coctek coir for the past five years. Be sure to get the fine-ground coir as the mixed coir is too stringy and will be hard to turn.

    We recently bought a case (24) of it which is way more than we want to carry but the price was right.

    Would be interested in sharing our case if you are near Port Charlotte, FL.

  18. Tom Geren says:

    Some thoughts: I bought the C-Head, and it has worked well-enough for me for the last two years as a solo liveaboarder. The “but” is that its smaller bucket must be emptied sooner. I can get two weeks per change with either coir or peat with paper in the bucket but I have settled in on about every 10 days because it gets harder to mix as it fills.

    Putting the paper in a separate container results in 3+ weeks for just me, and while I realize many around the world separate the paper routinely, I find it distasteful. That said, putting the paper in a separate container leaves the mixture in the head much nicer visually, and I think is the real key to virtually no odor.

    I have tried sawdust, kitty litter, peat and coir. My sensitive nose says the peat is best, having an earth essence which I can live with, and I found the coir difficult to obtain and expensive. None of the garden stores had it so I ordered from Amazon. The small bocks at the pet store are crazy prices. I found the coir prep a pain, and I think there is always a slight element of stink. Both peat and coir are messy with the coir having less dust.

    I have had one fly infestation when I became slack about the stirring of the container. The worst aspect of it was cleaning the bucket of maggot eggs. Fukishima radiation might do it in one shot but bleach and so forth took me 3 separate cleanings over a month’s time. I now toss a half cup or so of diatomaceous earth in the initial charge just because.

    At the 10 day point, obviously there hasn’t been much composting. The C-Head actually calls itself a porta potty. I c-a-r-e-f-u-l-l-y dump the bucket into a 13 gal bag as indicated above, and if feeling ecological that day, I disperse the mix at the base of a tree out of sight. This is fine without paper involved. The paper dissolves easily but is unsightly. But honestly, most of the time, I just toss it in a dumpster. The newer plastics these days seem to be biodegradable as well.

    All up, I now have just one engine intake thruhull to worry about, and once you get away from mixing the solids with the liquids, you won’t go back to black water soup.

    • We also have a C-Head, for about 6 weeks of full time cruising for 2 people, we use coir, and find it works great. We also just dump it in the dumpster most of the time. More challenging when guests are aboard. So happy to be rid of all the smelly hoses and holding tank. C-Head is also only $600, and is ridiculously simple to install and use.

    • Jim Shell says:

      Please do not randomly dump human waste on your garden or around trees unless it is thoroughly composted. Read for information about composting human waste.

  19. Jim Shell says:

    For smaller boats with a small crew, a “sawdust toilet” may fit better into the small head compartments ( and ). This is a non-separating composting medium toilet concept that goes about three days between emptying. No odor if managed properly (as with all composting toilets).

  20. laura dwan says:

    The only problem that we have had with ours is a build up if deposits in the piss pot (it has been 3 years) does anyone have a recommendation for something that will disolve them? Tt is really hard to get a brush in there to scrub it

  21. T. Cockrell s/v Sandpiper says:

    I have a question regarding the disposal process if you are dumping the mix on a tree or flowers. What happens with the most recent deposits? They would not be composted or do I misunderstand what is done?

    • That’s why most people put it in a dumpster. If you want to use it on plants, you have to let it fully compost which isn’t practical unless you have a composting bin ashore to put it in.

      • Tom Geren says:

        When I mentioned disposal at the base of a tree it wasn’t to mean where it was visible or on a fruit tree providing edible fruit. And, obviously, you could dig a hole, and bury, but the poop mixed with the medium will be gone after a good rain.

        After much ado with how to legally dump my RV black water/grey water tanks, and locating dump stations in the sticks, I tried an experiment. I was deep in the woods for a couple of years. I dug a small hole downslope twenty feet away from the RV, left the tank valves open so that the grey water regularly flushed the hose. I checked now and then for issues. There were none. When I finally left, you couldn’t tell I was ever there.

  22. I suppose using salt water to moisten the coir is out?
    We have a nature’s head, too, but haven’t lived aboard yet with it.

  23. I’ve been interested in “composting” heads since 2007 when I first heard of tiny houses and living simple with less environmental impact. I ended up putting an Airhead on my boat, but haven’t used it yet. I have one coir brick expanded, filling up the tank and ready to use.

    One thing I’ve wondered is, when out traveling away from the US, what is the availability like for materials to be used in the AH, NH, C-Head, etc.?

    Good tips on this page, btw. I just found this site today. Thanks!

    • I don’t know of anyone who ever couldn’t find SOMEthing. Friends often used sawdust, which can be found almost anywhere.

    • Jim Shell says:

      Unless you are in Canada, maybe few other 1st world countries, you can pump overboard. Check local regulations. For our use, we use a regular marine toilet with a holding tank. When we are away from pumpout sites, we use a sawdust toilet.

  24. Edward Tordahl says:

    I had the Natures Head aboard my MacGregor 26X “LAIKA”. It was perfect for that boat. I loved it so much, when I sold LAIKA and purchased my Pearson 323, “SEA HAVEN”, I reinstalled the original Sanipotti, took the Natures Head and installed it on “SEA HAVEN”. Unfortunately now that “SEA HAVEN” on the market, I cannot cost effectively reinstall the old holding system on “SEA HAVEN”, so I WILL be purchasing a new Natures head on the next boat.
    Suffice to say I’m a lifetime fan.
    As for the material, personal choice since I’ve used both peat and coconut an found it 6 of 1, half a dozen of the other. Never thought of Saw Dust only because of using what’s recommended in the owners manual.

  25. I like the compactness of the coir bricks, and they are readily available at garden shops, pet stores, and, of course, Amazon. I like the cypress sawdust we generated in our boat-paneling and cabinetry projects even better, as ‘free’ is good. Even better, if it has a nice aroma. I don’t use peat because, first, they aren’t making any more peat bogs, and second, some people have had trouble with Insect hatches from the peat.

  26. Have used peat, coco coir, and pine cobble cat litter. These days I’m liking a mix of coco coir and pine cobble. The experimentation continues

  27. We are currently using cypress sawdust and shavings as the desiccant In the solid waste bucket of our C-Head, Left over from paneling our interior with local cypress t&g, it’s free, pleasant-smelling, and readily available. We have also found coir to be satisfactory, easy to store, easy to reconstitute in a big ziplock plastic bag, and bug free. Amazon ships the stuff anywhere. I have avoided peat for three reasons: 1: peat tends to be dusty, harder to clean up after. 2: some have had substantial trouble with peat containing insect eggs, and hatches at sea can be obnoxious. 3: As previously noted, peat is not renewable, but the world has plenty of coconut fiber and sawdust.
    As we are not yet long-distance cruisers or full-time live-aboarders,my husband treats our C-Head like a no-stink litter box, scooping the dried solid lumps and TP out a day or two after a weekend afloat, and that way a refill lasts us for months, with no smell.. Thence double grocery-bagged and dumpstered. Works for him, and thus for me. We empty and thoroughly rinse the pee jugs, (disposable gallon plastic water or milk jugs) daily, if possible. Urine is what soon stinks, and I don’t love the idea of saving it in quantity. I assume when we get far enough along on this decades-long building project, we will use the head much more intensively, and revert to the whole-bucket-dump every two weeks into the provided secondary 5-gallon bucket, and quarterly dumpster trip with a plastic garbage bag. Either way, it really is no more trouble than taking out the galley trash.

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