Winter Cat Litter Composting Bed

Heaped up with straw, fall leaves and compostable cat litter waste, this worm bed should be relatively easy to keep warm this winter!

Back at the beginning of November I wrote about my fall clean-up efforts, and promised to provide you with an update on my outdoor cat litter composting experiment. As some of you will recall, I filled up one of my backyard composters with compostable cat litter, along with peat moss and other compostable materials, and then basically left it to sit (once the level was nearing the top of the bin). In my last update (WAY back in August) I reported on my pleasant, and unexpected, discovery of a thriving Red Worm population in the bottom of the bin. I had been holding off from actually stocking the system with worms simply because I assumed the habitat in the bin would still be inhospitable for them. Yet another example of how Red Worms NEVER cease to amaze me! (have another prime example of this coming up in another post, by the way!).

Given the fact that this ‘regular’ backyard composter is totally unprotected, I knew that something would need to be done in order to make sure that the resident worm population survived the winter (although, have I mentioned that Red Worms tend to surprise me from time to time? haha! One winter I had a population survive unprotected in this exact same bin). I settled on the idea of spreading out the contents of the bin on one of my (non-food-crop) garden beds, then simply covering it with a layer of straw. Recently, I have decided to take things one step further.

What follows is a series of photos and captions documenting the process. I will also add some final thoughts afterwards, along with links to previous cat litter composting blog posts.

**WARNING** – Some photos show cat turds – viewer discretion is advised (don’t scroll down if this sort of thing bothers you). Also, be aware that cat litter composting warrants some caution, and should generally only be attempted by those with previous composting experience. Any dog or cat waste composting systems should dedicated to those waste materials alone (i.e. don’t toss them in your ‘regular’ compost bins), and should not be set up near any water sources. Cat litter shouldn’t be handled at all by pregnant women or young children.

Ok, you’ve been warned – you may now proceed!

I was surprised by the success of the cat litter composting in one of my backyard bins this past summer (especially given the fact that a substantial population of worms became established without any assistance from me), but definitely didn’t want to let the contents freeze solid over the winter

Contents of the cat litter composting bin, spread out on one of my garden beds (one not used for food crops, in case you are curious) then moistened.

Covered with a first layer of straw – originally planned as my only layer of winter protection.

Material from my backyard bin – I figured this bed was as good a spot to add some as any. This is actually what got me to start thinking about upgrading the bed to a full-fledged winter composting system.

Before adding more compostable cat litter I wanted to make sure there was a bit of a buffer zone, so I added some fall leaves.

Multiple bags of cat litter waste were then added.

First layer of cat litter was covered with straw, then new litter deposits were added. First I lay down leaves, then brown paper, then the litter waste.

Each of these additional litter deposits was then covered with more leaves

Finally, everything was covered with a thick layer of straw. I will eventually add a couple of tarps, but I want to allow the system to ‘air out’ for a while first.

As alluded to in the last caption, I’ve been somewhat worried about adding tarps over the system too soon – the last thing I want to do is kill off my worms with excess ammonia gas. Most of the litter waste that was added to this bed (apart from the material from the composter, laid down as the first layer) has been sitting in bags, so it certainly hasn’t been given a good opportunity to age and off-gas any ammonia.

What’s really cool is that we ended up getting a huge downpour the evening/night after I set up this bed. This should REALLY help since it will not only moisten everything nicely, but it will also likely help to make the cat litter wastes a little more worm friendly. I am still going to leave the tarps off for now – and for the next few weeks will likely only use them if I know we are going to receive a heavy snowfall.

As far as adding new waste materials goes, I plan to only add a relatively small amount at a time from here on out, and I will make sure to create a bit of a buffer zone (using fall leaves I still have left over) around each deposit. I will also likely add some cat litter waste to the original backyard composter (some excess has already been added there) – since it has been totally cleaned out I won’t need to worry about a new worm population becoming established. It will basically just serve as a holding bin until warmer weather arrives in 3-4 months.

Anyway – it should be really interesting to see how this progresses! One thing is for sure – by the time spring rolls around this bed should be absolutely LOADED with fat Red Worms!

Previous Cat Litter Composting Posts
Cat Litter Vermicomposting
Cat Litter Composting – Update
Cat Litter Composting – 12-02-08
Cat Litter Composting – 01-05-09
Cat Litter Composting – 08-07-09

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Previous Post

Mark’s OSCR – 12-04-09

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Winter Worm Windrow – 12-03-09


    • Bob Packard
    • December 4, 2009

    Hi Bentley, sorry we haven’t posted for awhile. After reading this post I felt compelled to bring a website I recently stumbled on to your attention. (But you may already know about?) The site is Two very interesting subjects are covered in great detail and are very easy reading. When you get there look at the books and publications section. The two are titled “Humanure” and “Balance Point”. They are both free for reading online. The writer is obviously a strong believer in sustainable living. Let me know what you think.

    Hope you and your family have a very wonderful and blessed holiday season.


    • Kim from Milwaukee
    • December 4, 2009

    Great post, Bentley. It’s not surprising that worms ‘came out of nowhere’ to chow down on the kittyturds….it seems that worms are self-sustaining, from what I’ve learned from your experiences and my own. I have a compost bin located on a cement slab next to my trash cans, and last summer I found huge worms in the finished compost. Now where the heck did they come from? It’s not located on soil, so somehow they migrated? Worms are the most amazing creatures.

    I’m a huge fan of Joe Jenkins as well, as your poster above mentioned. Closing the cycle of nature is exciting to think about, and so easy to implement, and it creates wonderful soil in the process. Kittyturds want to be composted by worms, and our wastes do, too.

    • Bentley
    • December 4, 2009

    Hi Guys – nice to hear from you BOTH!

    BOB – I have definitely heard of Joseph Jenkins, and in fact I own a copy of his “Humanure Handbook”. I still haven’t made it all the way through, but I must say he did an excellent job with it! I have not read seen “Balance Point” though – will have to check that one out! Thanks!

    KIM – I totally hear you re: worms seemingly appearing out of thin air. I recently found BIG worms in plastic bins containing coffee sludge (grounds that had been rained on). These bins don’t have holes in the bottom, so I have no clue how the worms got in there, much less SURVIVED the pretty hostile, anaerobic conditions!

    Worms are cool – that’s for sure!

  1. I have a question about the kitty poo…is it ok or appropriate (or non lethal!) if we scoop it out of non composting litter (typical clumping clay stuff) and put that into worm habitat? I only have clumping liter right now because it’s the best for in house with 6 cats and a daughter I’m trying to convince to help out with chores in a timely manner…if you get my meaning. Ugh.

    Otherwise I guess I’ll go a different route. A friend of mine uses cedar sawdust from a local mill and just throws the whole thing out into a composting area. But what about the cedar? It takes forever to break down is my understanding and may have too many oils. Hmmm….unknown at this point what I can do without the clumping stuff. I can’t afford the pine liter all the time that is for sure.

    Any ideas would be helpful on what I can really do with all this poop. (goats, rabbits, cats, dogs and chickens) Dogs and cats are the biggest problems so far. 🙂 4 big dogs, and 6 cats…we are nuts!

    • Bentley
    • December 16, 2009

    Hi Christine – I have done that before myself. I guess the only thing to watch out for is a build up of the clayey stuff. Please don’t laugh too hard, but back when I was young and foolish I actually tried to compost ALL of it! lol! What a mess – it was like a clay-sludge cake with cat turd inside! Positively delightful, I tell ya! 😉

    Cedar is really risky to be totally honest – I definitely would steer well clear of it.

    I am jealous of all your poop (I never imagined I would utter that sentence in my life) – the goat and rabbit poop is REALLY prime time stuff since it won’t need nearly so much special care before the worms can chow down. All the other poop is great too, but generally should be mixed well with some sort of bedding then left to sit for awhile (outside!!! haha)

    Hope this helps! (and sorry for the delay)

  2. Oh Man!!! I’m so excited I can work this stuff through then! Woot!! Now I can terrorize my husband with my new poop ideas while we sit and enjoy breakfast together O.o

    Seriously, the poor man…Maybe it’s just because I’m a mom of two and have changed a ton of baby diapers, but the concept bugs me not. I can blab about it any time of day or night, but seem to have a real penchant for discussing whats on my mind while we are eating — and what is always on my mind is what to do with all this manure. :-/

    4 BIG German shepherds (and one Chihuahua, but he barely counts – that falls into the cat turd category – but I can’t seem to find his stuff…except when he gets too freaked out my heavy rains and poops on the deck. Dang nab dog)

    6 cats

    50 rabbits

    3 goats

    23 chickens

    A ton of poop and a ton of poopy hay from rabbits and chickens.

    The more we can get these worms going on the better. We have 15 indoor bins but now we are looking at how best to do out door containers beside the one tire. I hate tires but Joel is right, they are free and they keep the worms even warmer through winter *grumble* We rarely have hard winters out here on coast. As it pertains to snow and or freezing temps anyway.

    So back to the subject of doo doo — I appreciate your knowledge on this. It’s beginning to get a little out of hand. Especially the dogs. Carnivore doo is the worst for smelliness but if we can layer it nice (and keep the chickens OUT of it…(they seem to think that is the best place to find worms, hmmm…) then we may start getting somewhere.

    I gotcha on the kitty clay cake clump. Ugh. We have one of those on the edge of the driveway as we speak. We sort of stand around it wondering how best we can facilitate it going back to nature. (like road workers, ever notice how there is one man working and everyone else standing around watching him work and “discussing”? Thats us around the block of “stuff”) We tried blasting it with water. I suspect we shall have to pick it up by hand. Egads!

    Good thing we live out in the country LOL.


  3. Oh yeah, and one more thing…biting flies lay their eggs in poop. Any kind will do. Typical house fly type flies? They lay their eggs in dead things (for the most part)

    So we buy fly predators. They go after fly maggots in poop. They look like little wasps. And they do wonders!!!! So I will be putting these eggs into the mix around here. Gets crazy with flies as you can imagine.


    • Bentley
    • December 27, 2009

    Hi Christine,
    With the potent poops like cat, dog, poultry etc, i would definitely mix them up with a lot of bedding materials then let them aged in an outdoor heap for awhile. Maybe add a thick layer of straw over top to discourage various annoying pest (like the flies you mentioned) and to prevent everything from getting drenched constantly (get the feeling you guys get a lot of rain).

    I know exactly what you mean about the biting flies that look just like houseflies. I often get a bunch of them in my basement whenever I bring in aged manure. That’s really cool re: the wasps – I didn’t realize there was a bio-control organism available for those flies. What is the variety of wasp, and where did you get them? If it’s ok with you guys I’d like to share that info with the group since I know these biting flies are a common pest among us “worm farmers”

  4. How long do you think the piles should age? One of our thoughts was to layer in and out with bedding and poo and other organic materials…let it rain on it a bit here and there but then get it covered. Should we keep it covered for a period of time? And really, I will likely need to keep it covered once the chickens are back out again. They don’t come out when the rains are heavy, but they will if it’s misting. The will go right through the pile no matter whats in it. So we do have to manages these guys, at least through the winter. Once we plant the garden, the chickens won’t be let into that part of the yard any more.

    The fly predators we use are from these guys and they are flat out awesome. It really does work, especially if you keep it up over the months the flies are out. I was skeptical at first. I got a flyer in the mail from a goat supply company that I ordered from. I was getting desperate though because we were all getting chased indoors but the animals had no where to go. I bought a hundred of the fly tapes and it worked a little for a short amount of time, but not enough as you can imagine.

    Anyhoo, I did order these little guys and they do work. Just one word of warning…don’t wait to put the guys out for too long once you get them in the mail. Really watch when they start to come of of there pupae stage, then get them out to where they need to go..otherwise they are all over the place and just die in your house without food. I waited too long on one of them because I got busy doing other things. They were in my house for 2 weeks instead of the 5-7 days. Not good 🙁

    Give em a shot, I can’t say enough about the little buddies. But they do go after the flies in the larval stage, nothing can be done in the adult stage…from these little guys any way.

  5. Oh yeah, and the rain we get…a bunch. We usually get about 140″ of rain a year. Sometimes it can get upwards of 200″. 12 feet deep…about the depth of an Olympic swimming pool. Very very wet. British Columbia coastal…we are right there in the same ball park of rain. In fact, we are just across the strait from Vancouver Island.

    • Bentley
    • December 28, 2009

    I would suggest waiting until the material no longer has a foul (or ammonia-laden) odor. If it is starting to get a bit of an earthy smell (while still a little gamey perhaps) you should be in the right ballpark.
    I would let it get a good soak before completely covering it, but yeah, no use leaving totally exposed to the rain once it is nice a wet. Again, just make sure there is lots of bulky and/or absorbent stuff in there as well to help encourage air flow!

    Thanks for the info on the wasps!

    • Charles
    • October 7, 2015

    As this says, the best insurance against problems with pet waste compost is to keep you pets healthy!

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