Throwing Away Billions of Dollars In Pet Manure


Not until I was well into writing my new book, Holy Shit: Managing Manure To Save Mankind, which is about  how to manage manure for soil enrichment, did I realize that cats, dogs and horses are a very significant source of valuable fertilizer that we are mostly throwing away. Or, as our friends’ cat, Django, indicates in the photo above, flushing it down the toilet. Until I got to know Django, my attention was focused on farm animal manure and human manure.  I was really surprised to find out how much feces, urine, and litter that pets were adding to our overflowing waste stream, let alone realize that cats were learning how to use the flush toilet.

Instead of wringing hands over the problems of livestock manure, the non-farm sector of society might first want to take a closer look at its own problem: manure from pet cats, dogs, and recreational horses— animals that have little or nothing to do with putting food on anyone’s table. According to recent statistics, there are 73 million pet cats in the United States in addition to an equal number of feral cats roaming the alleys and fields (and killing millions of songbirds). There are some 68 million pet dogs and of course millions of strays out there doing beneficial work like killing my sheep. In addition there are some 9.5 million horses and the number is rising.

The numbers I use in Holy Shit to calculate the amount of manure flowing from these pets can only be approximations but they are based on the best statistics I could find. A horse weighing a thousand pounds produces about 20 tons of manure a year including bedding. So unless I can’t multiply any more, 20 X 9.5 million equals 190,000,000 tons of road apples. Pet dogs and cats together produce per year another five million tons of manure.  All this waste is good, holy fertilizer. Dog and cat waste is particularly valuable because, compared to most manures, it is higher in phosphorus, the plant nutrient most difficult for organic farmers and gardeners to come by naturally.

Only a small fraction of this manure is being used for fertilizer however. Most of it is going to landfills or to sewage disposal plants as pet owners get rid of the manure by way of dumpster or toilet. Pet owners are supposed to pick up manure when they walk their dogs (which they then flush down the toilet or put in the garbage) but when I walk  public park areas, I see droppings all over the place. And of course the urine, which is richer in nitrogen, phosphorus and potash than feces, just disappears into the public grass— or more often, the neighbor’s lawn.

This waste is particularly worrisome now because the cheaper sources of commercial fertilizer for farming are declining. Competing uses for natural gas, our biggest source of nitrogen fertilizer, is driving up prices. Potash deposits in Canada, our handiest source, are declining, and talk of opening up new mines in the rainforest does not sit well with the environmental community. Some specialized phosphorus fertilizers are very expensive. The day is coming when we must start thinking about scrupulously saving our wastes for fertilizer as humans have done, especially in Asia, for centuries.

Django is not going to appreciate this but, as I write in the book, the possible specter of 73 million cats perched on toilet bowls across the nation causes me to shudder. Doubtlessly training cats to go on the pot is rather clever and saves messing with litter boxes. But with the tiniest bit of effort, litter boxes can be dumped into compost piles instead of flushing them down the toilet. I wonder if cats will learn how to flush the pot too. Will they do like children do sometimes, and flush the toilet just out of boredom when master is not around?  Or maybe flush master’s slippers down the pot?  But whoever does the flushing, let us contemplate seventy three million toilets flushing ten times per day just from cat use. That would take something like 36.5 billion gallons of water. Every day! Now add on the incalculable number of flushes from human use and you have a demand that the experts say would be impossible to meet if the whole world lived like Americans.

What are we throwing away in money? In Holy Shit I use my own way to come up with a figure. You may agree or disagree. Experts say that ten tons of animal manure and bedding per year can adequately fertilize an acre of farmland. Therefore we have enough pet manure in this country to fertilize something like 20 million acres every year. If a farmer is paying out $100 an acre for commercial fertilizer (right now it’s lower than that, last year higher) we’re talking about a value for pet manure of something like two billion bucks. And the cost of throwing it away in the landfill or sewage treatment system is a whole lot more.

Just out this week from Chelsea Green Publishing, White River Junction, Vermont


This is a serious question. How many inches of cat poop do I need per square foot of garden? I just got a couple of kittens using a litter box which is filled with dirt from the garden.

How long should it be buried in the garden before planting there? It seems to disappear in just a few days when I put it in the garden.

Their food is all organic, so I’m not worried about chemical additives.

My day job is being a stockbroker, which probably explains how I’ve become so familiar with poop over the last 10 years.

Dave, how do we make a full length post? Is there an email to send it to?


    Gershon, et al: If you would like me to publish a post, send it as a comment, which I moderate. Head it with “Please Post”. If you have a photo, ask me to contact you for the photo. -Thanks. Dave

Gershon, I don’t know what your day job is but you should seriously think about writing humor instead! You and Gene between you (not to mention the other talented folks posting on this blog) really tickle my funny bone. Gene, what about giving us your planned topic every so often ahead of time, and we’ll each write a post? Who knows, we might get something started and bring a lot more readers to the blog. I figure the more folks we can interest in such topics as poop, pee, haystacks and gardening, the better this old world will be.

    The Contrary Farmer eagerly invites full-length posts from its readers, subject, of course, to acceptance. Tomorrow’s post from Gene is about transplanting tree seedlings. -Dave

Actually most of the cats think it is great fun and race about chasing the rocks………so I guess we both derive some entertainment from it. Then I give up and put a cage over the carrots 😉

Sealander: phosphorous aside, you should probably stop throwing rocks at the cats if you want a carrot garden instead of a rock garden. I have mental image of a couple of scraggly carrots peeking up through mounds of stones strew across the horizon. And what is that in the distance??? It looks like a group of cats sitting on the fence with contented smirks on their faces.

So all those dratted cats that keep digging up my carrots were really just making phosphorous donations to me? Guess I’ll have to stop throwing rocks at them then 😉

You know, I just can’t resist carrying on with this. Gershon, my mother was of the REAL PROPER variety. She could not bring herself to say sex, for example. But she said shit every time she got mad at something. We children would reprimand her for saying a bad word and her answer was invariably: “My mother was a saintly woman and she said shit, so I will too.” But we kids better not say it where she could hear it Gene

Hmm, maybe the sense a poop should have an electric crank thingie to grind up the poop. It has to be done when fresh as my mother used to say “Don’t stir up old poop, it stinks.” Thinking I should write a book “Mom’s Shitty Wisdom.”

Love your humor, Gershon. Yours too, Ohiofarmgirl, in your comments and on your blog. I never before heard of a broadcast seeder referred to has a “handcrank thingie” Wouldn’t it be fun to do a catalog on the basis? “A ‘handheld diggie thingie’ — ‘works well for burying Mon-poop or home poop.” Gene

I just had a horrible vision of the future if using pet poop becomes popular. It might be that now, if I plant some flowers in a pot, it would be a good thing to visit the litter box and scoup a poop to put a few lumps in the pot. The next step, which already exists is to make a Sense a Poop which would scoup a poop from the box everytime the cat visited and get the poop all in one container. This is good for the cats and for the collector. It saves liter, too.

But then, it would become corporatized. Someone would create a special feed for cats they could call Maxi-poop. The purpose would be to be mostly undigestable and create as much “product” as possible.

Instead of living in homes, cats would live in cages so they don’t turn any food into movement instead of poop. They poop would be sold under the brand name “Mon-poop.” (A play on words in French for “My Poop”.)

Then laws would be encouraged which would require a new branch of the government to inspect a poop. The licensing requirements would be so expensive that only the big poopers would be able to afford it. People would be taught to believe that home poop is unsafe and they need to buy Mon-Poop.

Soon, third world countries would get into it with the help from the UN which would propagate the Western way of doing things. There would be no more collecting poop from homes. In fact, having home poop would become against the law and all the cats would be nationalized.

Every so often, a story would be published about the dire end of someone who used home poop in their garden to create fear among people so they don’t buy from small producers.

Cats would be bred to make the biggest poops and would become little more than intestines. The ability to move wouldn’t be important except for bowel movements.

One day, there will be a story about a disease that was spread by “Mon-Poop” and people will then want local poop from free roaming cats. And the war will be on between Corpo-poopers and home poopers.

Most of this has already happened with chickens and cows with eggs, breasts, and meat being the equivalent of poop.

Gene – all my cats can rest easy now that I understand the value of their poop. For years they’ve tried to convince me NOT to scoop the box… I think they were telling me to use it wisely.
Anywhoo… we’re having a Gene-love-fest over here:

Pardon the silly goat picture….. and congrats on the book! I’m doing my best to promote yours in the comments on this post.

And to cap it all, I just saw a web article about a car that runs on human shit! Now, that’s recycling!

DennisP thanks so much. That article reads like it came right out of Chapter 12 of Holy Shit. Gene

On shit in general and running out of phosphorus, here is an interesting article I just read this morning by the Asia-Pacific editor of the Sydney Morning Herald:


Yeah…what Beth and Julie said…do it, man. Actually, I think its a very special talent to be able to write to the perceptions of a child. Maybe you’d want to team up with or empower someone which such skills and mindset if its not up your alley, but in any case there seems to be the beginnings of a groundswell here.

Gershon, I understand what you’re expressing about the purity of shit. There’s a lot of crap in the crap sometimes. I am a huge fan of shit. But if one of local hog confinements offered me all I wanted I’d pass. That’s not about shit, though, that’s about hog confinements and the insane practices they engender. Someone would have to prove to me though that it was what was in the horse manure that killed the garden rather than improper aging or application. I just can’t imagine what someone would give a horse that would kill the garden without killing the horse. But even if it was so, it’s not an argument against what’s being discussed here and in Gene’s book. You can overdose on fat soluble vitamins. That’s not a reason to avoid vitamins. I think your example presents a case for awareness and intelligent use rather than avoidance. All the more reason to start them learning young with Gene’s upcoming children’s book. And since potential titles are being bandied about, my contribution is Pooh Pooh Pee Do.

YES! A children’s book on how to use your poop! I’m a mom, and I would totally buy it. For all my nieces and nephews, too.

David, you are so right. Little kids don’t have fecophobia (love the term!), adults teach it to them. Any parent who’s ever walked into the bathroom to see a toddler fingerpainting with his excretions recognizes that to a small child, shit is just another way to express herself. Why do so many humans think they sit outside the circle of life and death? I suppose it’s easy enough to do when you live in a highrise where everything is magically taken care of: food can be ordered in with no labor on your part and what your body doesn’t need is disposed of by a single flush. But when you’re walking in poop every day–milking the cow, feeding the pigs and chickens or spreading it in the garden, you begin to have a reverence for the stuff. I’d love to see a children’s version of Holy Shit, Gene. You could call it Poop, Poop, Wonderful Poop!

I grew up in Belleville, NJ which is right next to Nutley. Nutley was the first city in the country to have pooper scooper laws. People bought a can with holes in it to sink into their lawn and just disposed of the poop there.

I’ve told a neighbor that if his dog poops on my lawn to leave it there as I appreciate the fertilizer. But he still takes it home in a plastic bag. It’s not just poop, it’s plastic that is disposed of.

I’m not a big fan of shit as I am concerned about the things that go into it in today’s world. People have lost their entire gardens using horse poop because they fed on stuff that had been treated with some chemical. Who knows what they are putting in pet food? I’d use it on flower beds, but not on vegetables.

There is a family of poop I’m guessing you haven’t addressed in your book. Insect and microbial poop. My intuition tells me they provide more poop to the world than cows. Every bit of organic matter that falls on my garden turns to poop eventually. If I put 100 pounds of organic matter in my garden a week, it will eventually turn to about 20 pounds of poop. (The difference is the water content.) I once weighed myself before and after taking a poop and didn’t even notice the difference. (Don’t ask, it was part of a competition on who could lay the biggest poop. The things college kids will do for fun.)

As I’ve been doing this, I’ve come to realize how much land must lose fertility in order for my garden to gain fertility. The things I can do on my home garden are impossible to scale up, so I can see why farmers resort to chemical fertilizers.

The common factor is transportation. As I read about the Polyface farm in “The Ominivore’s Dilemma” I came to realize that an important part of sustainability is avoiding transportation costs and effects. I also have come to realize the human’s part in the cycle of growth is transportation of fertility. Every time we scale up above what a single person can do to support themselves, we introduce inefficiency and unsustainability. On the other hand, we also increase short term survivability as we don’t have to worry as much about crop failure.

It would be nice if we could imitate the ways China supposedly kept areas fertile for thousands of years, but I doubt if we would like the lifestyle. We probably don’t even know what those ways are anymore.


Thank you for your very generous acknowledgment of what I wrote. Most of people’s thinking about shit is about making their doodoo go away with the least possible direct involvement. Because they think of it as waste. I think its a mistake to call it waste. Its only waste if you waste it. The name of the game is nutrient recovery, as those with the gumption to obtain your book and read it will discover or learn in greater detail. Its an endless circle of nutrient recovery. The only way it works is if the circle is complete. You can’t tear a chunk out of the circle without creating a flat line (to Hades).

OMG, I just had the brainstorm of the century–Gene, you should follow this book up with a version of the book for children. Every 10 year old boy on the planet would be empowered to talk about shit as much as they wanted. You’d probably have to hire personal security to keep irate parents from tarring and feathering you, but it would be worth it. I’m absolutely serious. I think there needs to be a children’s edition of your book in multiple languages.

Meghan F Yes, my book covers human waste in depth. You are to be honored for using a compost toilet— and a homemade one yet to boot. Hooray for you. Gene

Just curious, does your book cover human waste? If so, I’d love to read your perspective on it.

My husband and I have been using a homemade compost toilet for a year and a half now, and we love it! It’s nice knowing we’re not wasting water and money disposing of waste in the culturally acceptable, but wasteful way.

I’m proud to report that we’ve been composting pet waste for 4 or 5 years now, and you should see the size of my tomato plants! Our favorite cat litter is corn-based. Cat boxes get emptied into a compost bin that will age for a full year. The guinea pigs use a paper-based bedding that makes a nice mulch, but also promotes volunteer tomatoes or whatever we’ve been feeding the guinea pigs.

I tried some “compostable” bags for picking up dog poop on our walks, but so far they don’t seem to be performing as advertised.

David Z, I couldn’t say it any better, bless you. I tried to say it better in the book but you’ve got me beat. Gene

We have two ‘work cats’ outside that keep the rabbits and moles out of the gardens. The occasional bird is looked at as dessert. Our two house cats (non-productive animals as I refer to them) have litter boxes in which we use ‘Yesterday’s News’, a recycled newspaper product. This litter goes directly into an unused section of garden or under one of the plum trees. The very best garden I have is where the litter and poop from the chickens has gone for a few years. No has gotten sick from the peas, onions, cabbage, spinach, and raspberries that have grown there. My dad always spread a couple loads of cow manure on the garden before spring plowing when we grew up on the farm and, surprisingly, all 6 of us survived. I can’t begin to count all the pickup truckloads of horse manure I hauled from a local boarding farm to my gardens and blueberry patch and our 3 kids all survived. Even the grandkids have eaten berries and vegetables from the same manure-infested gardens and still live. Lucky bunch, aren’t we?
I can’t wait to get a copy of your book so I can get new ideas, but also to set out in prominent display to the shocking dismay of my germaphobic son and daughter-in-law (though they let the kids eat anything I grow). What joy to be a Contrary Grandpa!

Keep up the good writing Gene. I’m afraid that common sense is not making a comeback in this country any time soon, but you, and a few like you, will help keep the candle burning in rural America.
God bless you.


Yes, the paranoia (which I prefer to call fecophobia) is alive and well. Few stop to consider that these “deadly pathogens”…uh, come from inside themselves… They’re little bitty bacteria, different from the millions of essential bacteria that are also inside of us in that we don’t handle their waste products as well as we do waste products of the ones we call ‘beneficial’, which indeed many of them are. Few also, apparently, fail to realize that if these are indeed the deadly pathogens, there’s a terrible irony in dumping all of this stuff into a very limited supply of potable water as you mentioned. I don’t think its quite so dire a threat as some do I guess. I see my dogs and chickens eating it when they get the chance and they’re all still around, and for that matter pretty spry. None of my dogs, though, will touch a diet Pepsi. I don’t know if its the aspartame or if its something else. But if the USDA says its OK folks will put it in their mouths…the nitrates and nitrites and BHT and all the rest of the stuff that’s only initials because no one could pronounce it anyway, the irradiated stuff, the genetically modified frankenfoods, the allowable (even though ‘pathogenic’) bacteria counts, pesticides residues, processing contaminants to mention a few. Seems to me that the situation could be remedied literally overnight if it were possible to win USDA approval for humanure and cat shit. Maybe not for direct consumption as my dogs and chickens prefer, but somewhere in the food chain. Because if the USDA says its food, then by god its food and America will eat it. I mean c’mon, it can’t be THAT much worse than seafood laced with petroleum dispersant that is on its way to America’s dinner tables. The Chinese put, not thermophilicly composted sewage, but raw shit on their crops for 5000 years and there are still more of them than anybody else.

Hooray for Fluffy!
Deb S and Heather G and all other respondents worried about pathogens in cat manure. The book does sort out the yes and no of all this. Bottom line is that properly composted manure or manure aged six months to two years is reckoned by science to be pathogen free. There is very much paranoia about all this and the book discusses all of that too Gene


Finally, someone understands the value of my poop. I always go outside and neatly dig a hole a few inches deep and poop there. Rarely do you see me pee and poop in the same hole.

My poop goes right in the area where microbial activity is the greatest and it decomposes quickly to feed them.

There are about 150 million of us and 300 million of you. Sometimes I do eat a bird. I’m hungry. Do you think chicken nuggets aren’t made of birds? People eat many more birds than cats. They also run into more birds with their cars than we eat.

But I also do other things. I keep the rabbits out of the garden. I eat rabbits, too. Once I even dropped a rattlesnake at my human’s feet. I used up one of my lives on that one.

Maybe one day, I’ll write my cat house book.

(aka: gershon)

You wondered, and here’s an example of a cat flushing:

Looking forward to seeing the new book — and I’m assuming you cover how the different types of manures are handled so that they’re safe to use for crops, including human and cat? It’s my understanding that human and cat manures need to age for a couple of years, so that harmful pathogens die out. Our cat’s manure will get used someday… we use a wheat litter and currently it all goes into the largest of our composting areas, down to the bottom of the pile (there’s a space between a wall and the pile that tends to stay open. The dog goes wherever the dog wants to — generally out in the field somewhere. Afraid the human contribution is going to take a lot more work at this point, but someday…

Gene, my understanding is that dog and cat poo have pathogens that can be dangerous and that it should not be used in the compost pile (and certainly not for growing food). Guess I need to do some research.

Gene, I can’t wait to read Holy Shit! Every time we milk the cow, the grandkids grump about the smell from the cow flops or grumble because they’ve stepped in some, so we have a conversation about what I call semi-liquid gold. We talk about the processes of biological decomposition and how the “icky” stuff makes grass and fruits and vegetables. So far, they aren’t what I would call real converts, but their parents tell me the dinner table conversation now includes the occasional discussion about how cow poop makes zucchini–I would call that progress!

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