Manure Or Not To Manure?


Alpaca poop in here

Fine Gardening's guide to vegetable growing Grow just arrived, and I was glad to see a piece by Roy McGinnis in defense of manure.

Manure is beautiful. The first time I ever saw explosive growth in my vegetable garden was the year my neighbor allowed me to take a pitchfork to her sheep stalls and wheel the combination of straw and manure across the road and dump it on my planting beds. I promise you, I never noticed any such happiness on the part of my vegetables back in the early days when I used to fling handfuls of bagged organic fertilizer at them.

The manure cycle is beautiful. Waste made productive.  Mix a bit of livestock and some food crops, and you have complete self-sufficiency.

So I was profoundly shocked a few months ago when I finished the superb introduction to soil science in Jeff Lowenfels' and Wayne Lewis's Teaming With Microbes: A Gardener's Guide to the Soil Food Web and got to this thought:

Human feces and pet feces should not be composted because of the possibility that disease organisms might survive even the high heat of the composting process; for the same reason, we personally discourage the timeworn pratice of using other manures in compost. Why take the risk when you don't know what kind of antibiotics and other drugs were used to feed the animals. Who wants to be worried about E. coli?

Yeah, but!

Roy McGinnis ignores this issue, saying only, "While it's all right to add manure directly to garden soil in fall (farmers do it all the time), I've found that cow, horse, and bird manure are best if composted first."

The ever fair and sensible Jeff Gillman has this to say in The Truth About Organic Gardening: "The practice of adding compost, including composted manure, to soil is a good one as long as you compost appropriately." Gillman, however, does cite a study that found that E. coli O157:H7 can live in uncomposted manure for 21 months.

I wasn't happy to learn from the abstract that E. coli O157:H7 can survive in manure frozen at -4 degrees Fahrenheit for 100 days, because there we have my manure handling plan. I try to spread it on my vegetable beds at Thanksgiving, but this year I didn't get to it and just left the pile frozen and will spread it in April.

A quick look-through of the other papers that cite this one suggest that the science is a bit all over the place, from the truly horrible–slugs may be vectors for E. coli O157:H7, depositing it onto lettuces; lettuces take up E. coli into their internal tissues, where it cannot be washed off; E.coli can set up shop and live in the soil–to others that say what I want to hear: that even with sloppy, room-temperature composting, E. coli disappears after 28 days.

Am I giving up manure?  No. I trust that the waste treatment process in my garden soil is far more complete than that in any highly controlled study, and my manure does sit for a long time before it goes near a vegetable.

And has anyone ever gotten sick from the food in a home garden?


  1. In the research I’ve done on manures, I’ve found that manures from herbivores (cows, horses, sheep, chickens, and such) are less likely to harbor E. coli and other pathogens than manure from carnivores like dogs, cats, or humans. I use composed horse manure from a neighbor, where I shovel from the oldest piles she has sitting around.

    But don’t use manure for legumes or they’ll put out too much vegetation and not enough flowers. Plus they don’t need the extra nitrogen in the soil–they fix nitrogen in their root nodules in a symbiotic relationship with bacteria.

    Also don’t use fresh manure for acid-loving plants since it tends to be alkaline–composting tends to neutralize any alkaline or acid materials. I found this out when I planted some blueberries. (BTW, I bought cultivars that are adapted for Florida’s short winters and long, hot summers. They were blooming when they were delivered the first week in Feb.)

    The other item to remember about Lowenfels and Lewis’s take in Teaming with Microbes is they recommend brewed compost tea. This process, where you add sugar and extra aeration, creates a medium where unnaturally high populations of whatever microbes are in the compost. In this case it’s probably best not to use manures. See Linda Chalker-Scott’s take on this in her book and on her website: She’s cited the science on brewed compost tea at least three times.

  2. No, in my 35 years of consuming foods grown in home gardens fertilized with mostly horse, chicken and rabbit manure I have never become sick, nor have I known anyone who has become sick from eating the produce. I have become sick from eating food at Applebee’s.

    Never in a million years would I even consider using human, cat or dog waste in my compost. The risks far outweigh the benefits. Even properly composted to kill bacteria, the heavy metals contained in that waste are still an issue.

  3. I know the farmers here spread cow manure in the fields because I see it. I don’t know how or if they process it first, but it is usually dry and flaky enough to spread as a uniform layer.

    Other fields are used as feed lots during the winter which has a more random and concentrated application of fresh manure. These fields are then put into feed corn mostly come summer planting time.

    I just use my wood chips in the vegetable garden as an ongoing worm compost factory and might add a dash of bagged manure when planting.

    You can see my prepped veggie garden here:

  4. I used manure from cattle or horse, not sure which as I bought in a truck load from a supplier not a farmer. No sickness from it in our household and we had bumper crops of everything. I suspect that the note of caution in the writings mentioned above is a necessary disclaimer. I’ll still use it in the garden despite any studies. Of course getting an extra supply and dumping it in the compost bin might be a good strategy for next year.

  5. I’ll still use it. As Dave said, I see those warnings as more of a disclaimer than anything else. We add manure every year, and no one has ever gotten sick.

    Have to agree with Reading Dirt, too—that’s what soap and water is for!

  6. I’ve been eating home-grown veggies from family farms and gardens my entire life, and all of them included composted manure.

    I’ve never hesitated to enjoy a sun-warmed unwashed veggie, including root veggie – brush off the soil and pop it in my mouth. Everyone in the family does it, and no one’s ever gotten sick that way. I don’t remember ever seeing anyone in the family wearing gloves to get their hands in the soil either, (although I do now because in my ‘old age’ my hands dry out too much if I don’t.)

  7. “Science” is a key word in regards to manure and composting, because you might wonder how much scientific analysis has actually been applied. Do McGinnis, Lowenfel or Gellman ever site any actual scientific, peer-reviewed studies to back up their claims. I’m trying to think of a composting book I’ve read–ever–that referred to actual “science” being applied to manure or compost. It sounds like one of those earmark projects–although extremely useful to anyone who grows food–that John McCain would love to rant about. Or are we composters simply relying on accumulated anecdotes and common wisdom?
    I see from my copy of Teaming with Microbes that Lowenfells cited a number of written references in his bibliography, but no studies per se and no footnotes. “The Rodale Book of Composting” contains neither bibliography nore footnotes. We just take what it says on faith, I suppose. So where’s the science? Perhaps a soil scientist will step forward.

  8. Science ain’t the only thing that is a bit “all over the place”, poop and poop with E. coli 0157:H7 is likewise spread far and wide. Think about all the creatures walking through your garden, everything from microscopic animals to rodents, foxes and birds – none of them are wiping their feet.

    It’s easy to blame big agriculture for tainted food when problems show up in the supermarket. That’s not the dreamy way people are supposed to grow food. It’s easy to overlook the truth that no one at the farmer’s market it having every lettuce leaf they offer tested for E. coli or anything else, neither are home gardeners. One sample of soil or one sample of produce only tell us about THAT sample, we interpret the results to apply to the entire site when in truth it doesn’t. We just don’t know enough. Lack of knowledge never stopped anyone from forming an opinion but I think I will bite my tongue. Somewhere, someone has gotten sick from home grown produce but they may not have sought medical attention for it or for a million reasons the problem was not recorded and presented to us. This doesn’t mean it never happened, just that we will never know.

    I have similar problems with cleaning up after my dog at the park. The last thing we need to be doing with something like poop is sealing it in plastic and burying it in the land fill. But that is just my opinion.

    For my garden I use all the herbivore poop I can get my hands on and don’t think twice about it – but then I’m an ex-zookeeper and shit don’t scare me, and I’ve probably been exposed to things far worse than whatever lurks in my dirt.

  9. We buy dairy manure for our vegetables, but on the ornamentals we compost all the dog manure. In the summer the compost temperature simmers along between 120 and 150 degrees F. I am not concerned at all. We know our dogs are healthy and the plants are thriving. Also, Have you read “The Humanure Handbook”? The author has done some of his own research, sited studies, and visited large composting operations. Interesting, and humorous reading. The book is now available by free download.

  10. Pet and human manure are far different than that of cows and horses. Pets and humans consume meat.

    There is an article in this month’s Mother Earth News regarding a Dow chemical used for weed eradication that can pass through the manure and wipe out gardens. Check it out!

  11. Ed Bruske, if you follow my link for the study cited by Jeff Gillman, you will arrive at the website of a publication called Applied and Environmental Microbiology.

    There are several dozen abstracts on the page, all concerned with the survival of pathogens in manure.

  12. Personally, neither I nor anyone of my family have ever gotten sick on any of my home-grown, home-canned, home-frozen produce, eggs, or butchered chickens, geese, ducks or turkeys. The only poop I compost is that of the critters I raise here, as I kind of like to keep that loop closed. (I also compost–and I have huge piles so I can get away with this–the feathers and inedible viscera, and I bury the feet and heads, mainly because I don’t want to scare myself when I turn the piles!)

    The whole manure-avoidance thing smacks of “what you don’t know WILL hurt you,” but honestly I don’t believe that the nags down the road who aren’t even wormed with any regularity are going to be disease vectors of E.coli.

    But eating at Applebee’s? Maybe it’s my own fear of the unknown, but you won’t find me doing that either.

  13. This is one reason to get your manure from a good source. I have a local organic farm that I get mine from. If you’re hard core you should raise your own animals for manure, having a closed system is the best way to keep bag organisms out of your garden.

    You’re probably in greater danger of getting a weird bug if you eat produce from the grocery store rather than from your own garden that you put manure one. Or eating at a restaurant like others talk about above.

    I think we’ve become just a little too germaphobic in our society. I grew up in Colombia, S.A. and we were testing for amebas & bacteria when we came back to the states. We always had it but it never made us sick because we were constantly exposed to it.

  14. I loved the response by the one person who mentioned that that’s what soap and water are for! 🙂 I will never stop using manure for my garden. I think far too much is being made in the media about all the germs and such. Back to the simple life 🙂

  15. I was a kid during the war (WWII, the big one), and in a corner of our garden was a little cart and a shovel. When the baker or the milkman or the rubbish man or the ice man passed by, it was a good day if his horse lifted his (or her) tail and left us a present. My job was to grab the cart and shovel and run out to scoop it up before the neighbours could get there. Some we won, some we didn’t, but none of that stuff went to waste and none of us got sick either.

    Later in my life I lived in southeast Asia, where human waste was routinely used on the crops. Didn’t get sick there either, although our salads tasted strongly of chlorine. One thing I noticed there was that the pickiest people — the ones who were neurotic about “cleanliness” in their houses — were usually the ones who were felled by the first passing microbe. I totally agree — soap and water, and a dash of common sense.

  16. Maybe I can sound offensive, which I don’t want to be, but the alarming study sounds to me as an exponent of what we, here in Europe, consider as the exaggerated anxiety many American seem to have about bacteria.
    No, I don’t want to say that there aren’t dangerous bacteria, but to avoid exposition to bacteria can be dangerous too.
    Just use some common sense, and like Ginny Stibolt said, use manure from herbivores, and try to avoid carnivore’s manure.

    For me, I’m more concerned about the antibiotics that are left in the manure, than about E. coli. (That’s the reason I obtain my manure from a trusted source.)

  17. I was distressed to see that people are being discouraged from using cow and horse manure – except that most people who used manure from farm animals have been doing it for a long time, like me, or have seen neighboring gardeners do, like me, and try it for themselves. All with no ill effects. We do live in the country and manure is available. We see farmers use it. I do wonder whether we worry too much about germs, and not enough about washing our hands with soap and water. I’m happy that I have chickens and know what they eat; I consider their manure invaluable. I would never use pet feces in my garden or compost.

  18. See, I’m curious about that. I was thinking about adding a bit of dog manure to my compost. Maybe I missed out on some basic biology classes, but if my dogs eat kibble and not a raw diet, what’s wrong with their poop? Heck, I’ve even been told that dog kibble makes a great compost activator.

    (For that matter, when given the opportunity, my dogs will also happily chow down on cow poop.)

    This is my first year with my own pile, but temperatures in my neighbor’s well-loaded compost pile can reach over 200 degrees in the summer. (It helps that this is south Texas, where it can reach well over a hundred degrees in the air by itself in August, and the pile’s in direct sunlight.) What temperatures would the compost theoretically need to reach before it would kill the bacteria and/or break down any toxins that may remain from bacteria?

  19. I’d bury my shit in the ground before the dogs ate it. Bury human shit but animal shit is OK for tracking! I hope coyotes don’t kill lamb babies.

  20. Rotted manure is the joy of my life – – the garden loves it. From hostas to tomatoes to annuals. WOOT! Joy I tell you!

    In fact, it’s what helped grow my tomato that looks like a man’s butt – and every gardener should have a tomato that looks like a man’s butt.

    Shawna Coronado

  21. The antibiotics and other drugs quoted remind me of something I read recently about hormones from birth control pills being found in sewage water…where they can cause fish mutation. The practice of over-medicating, -engineering, and -fertilizing just because we can is inherently nonsensical. This article over at Grist talks about the latter, as well as how farm subsidies discourage an integrated agricultural system. At least the people around here have good old, manured, home-grown to fall back on…

  22. What makes me crazy about these sorts of scares is the conflation of ‘possible’ with ‘likely’. Yes, it may be possible for E. coli to survive composting, to live in the soil, even to be taken up into plant tissues. But is it LIKELY? You’re probably more likely to win the lottery than get E. coli from your garden produce.

    Scientists certainly need to study things that are possible even if unlikely. The misstep is when laypeople (read journalists) simplify the results and fail to understand the statistical likelihood of whatever it is happening.

  23. To my understanding composted Manure means that Cow or Horse Manure was left in a pile to “compost” for a season before adding to your Garden.Not added to the Compost pile.
    As far as adding Dog or Cat feces to the Compost bin,personally,I find that on the same level as adding human feces.I would not do either.Why can we not just have a Compost pile without any additives,”quick starters” or whatever else we think we have to add to a perfectly NATURAL way of dealing with Gardenwaste? Is’nt that why we want to compost in the first place?

  24. I use composted chicken manure on all of my vegetables, shrubs and perennials. I’ve never gotten sick. I’m a lot more likely to get sick from supermarket produce, unfortunately. This was a really good post.~~Dee

  25. Give please. I cannot believe that the inscrutable universe turns on an axis of suffering; surely the strange beauty of the world must somewhere rest on pure joy!
    I am from Kenya and learning to read in English, please tell me right I wrote the following sentence: “Work at home, maintaining internet work by mowing mediating off sales, requirements, and numbers when first in economy.”

    Thanks for the help ;-), Tekla.

  26. My cats have peed and pooped in my veggie gardens for over 20 years and I’m still here. The worst they’ve done is cause a strong cucumber seedling that I was looking forward to seeing flourish to shrivel up. My sister says her passionfruit vine loves left over cat food and she feeds her cats cheap tinned cat food which is fishy and meaty.
    I figure that if I get sick I’ll take some medicine.

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