Compost Heap. Horse Manure. Pathogens.

[Ed]

I have a couple of large compost bins on my allotment which I regularly fill with compostable materials from home, but this only accounts for a few percent.

For the most part, I go to the local riding stables where they bag up the horse manure and leave it outside for people to take for free.

In the winter time, when the horses are inside the stables, the mix is heavy with straw and bedding. But now in the warmer months with the horses outside , it is mainly stuff gathered straight off the paddock areas where the horses pass their days.

The thing is this. The bins are 4'x3'x3' and I just do not have the energy or strength to turn them. So , in effect they are cold compost heaps. I let the contents rot down over a 2 year period.

But is there a danger that the pathogens in the horse dung will not die off (as they would if I were operating a hot heap) and that my family could become seriously ill if I use this composted material on my vegetable plot even if it is 2 years old?

Ed (South-East UK)

[brooklyn1]

There is no concern with pathogens with manure from vegetarian beasts except perhaps if you know the beast to be ill with a disease transmittable to humans. In your case I'd be more concerned with viable weed seeds.

[Bob Hobden]

Pathogens in Horse dung? Please advise what and any scientific papers that back it up. I know it is a big carrier of Tetanus but not heard about anything else of concern. "No major human disease has ever been accurately attributed to the intimate contact human beings have had with horses for thousands of years. Veterinarians and vet students probably have the greatest exposure to true risk from horse manure. The horse has a very inefficient gut: it's a one-way throughput system. Horses are physiologically incapable of vomiting or regurgitating. If something gets stuck on the way through, the only way to get it out is by surgery or physical intervention. As a result, you will often find vets armpit deep under a horse's tail. Nevertheless, there has never been a documented case of veterinarians contracting illness as a result of this rather extreme true exposure to horse manure."

We use well rotted 1 year old stuff and have never had any trouble.

[Ed]

Weeds aren't a great problem for me.. I got the time and I love weeding most days. Most of my weeds anyway are in-blown from other plots so I always expect them.

But thanks for the re-assurance on the pathogens though. I'd hate to grow my own crops and then find I make my family ill.

Ed

[nmm1]

That is essentially true. There are very few diseases with sufficiently resistant spores that they will survive any form of composting, and most of those are extremely implausible. None will contaminate vegetables, anyway, and the only risk is getting the compost into a cut, eating it if you don't wash it off, etc.

The only ones that are at all likely are carried by cats and other carnivores, as you say. Worrying about tetanus and anthrax is not a productive activity ....

Regards, Nick Maclaren.

[nmm1]

Try anthrax.

However, with both tetanus and anthrax, you are likely to have trouble only if the dung comes from a stable where they shovel dead horses out with the bedding. Not generally the case ....

Regards, Nick Maclaren.

[Ed]

No, I not no expert scientist or nothing nor read scientific papers. I am just a gardener. But I see a few articles on the web that says if you maintain a hot heap then it will kill pathogens.. If you run a cold heap then these things are not killed off with the heat. Hence my concern.

[RJBL]

Cl. tetani; Cl. Welchii; various E.coli and salmonella strains and Cryptosporidium all are risks from the use of farmyard and stable manures. Historically, the biggest risk to agricultural labourers and gardeners has been tetanus and gas-gangrene infections of, often, very trivial wounds. The extent to which the organic veg growing fad has been responsible for the increase, over the last few decades is unestimated. Best to keep your AT injections up to date and wash and boil everything that you eat from your veg / salad patch

yrs rjbl

[nmm1]

A lot of such rubbish is written by Merkins, who manage to make Little Englanders look intelligent. You need to be able to judge which authors have Clue and which don't.

Regards, Nick Maclaren.

[nmm1]

Oh, nuts! WHAT increase in tetanus and gas-gangrene in the UK?

The historical dangers were because a LOT of farm animals died from tetanus, anthrax etc. and the spores were everywhere. Well, they still are, but are not transmitted by that route any more because of the efficiency with which infected animals are detected and disposed of. Yes, keep your tetanus innoculation up to date, but don't use two century old information as a guide to safe practices.

A lot of the others you mention are something that most people have some immunity to, or even aren't pathogens at all (for example, you NEED E. coli to stay healthy). There is also increasing evidence that preventing children from being exposed to them increases the risk of much more serious problems. Exercise your immune system and stop fussing.

Yes, of course, some people are at special risk. Don't START training your immune system in old age or when ill, and so on.

Regards, Nick Maclaren.

[Steve Peek]

Ed, your biggest concern should be whether or not the horse's paddock was sprayed with a broadleaf herbicide. The herbicide will pass harmlessly through the horse and wipe out you garden. Check with the source of your manure, it would be heartbreaking to have that happen. Cheers, Steve

[Bob Hobden]

I agree there are possibly some other pathogens in Horse dung but in practice they don't pose much of a risk to human health these days. Not worth worrying about provided you use normal sensible measures like washing hands etc.

[Martin Brown]

If the bins were more like 6'x6'x6' they would probably hold enough heat in the bulk material to become hot. I only turn mine once to put the edges into the middle.

A hot heap works a bit faster and it is only really hot for a few days. Mainly it helps to kill off weed seeds. My heaps go hot when I put a few cubic metres of grass cuttings on them in one go. I have had one up to smouldering. If you can add enough of anything to the heap at once with the right amount of water you will get it hot for a while. The horse dung will act OK as an accelerant, but if you want something that will encourage a hot heap then the proprietory mix Garotta (sp?) seems to work as well as anything.

I wouldn't worry about pathogens from horse dung either. And if you have access to plenty of straw and horse manure it is worth fermenting some to make your own mushroom compost. I might worry about that persistent residual pesticide that has been causing trouble in winter hay though.

Regards, Martin Brown

[Billy]

FarmI wrote last Oct. "I also spread horse poop as it comes (often almost still steaming) straight onto garden beds and it results in a huge worm population explosion."

I might mention that she is still with us, which argues favorably for the use of fresh manure. Most will caution against getting fresh manure on the edible parts of the plant (touching or splashed) for at least 3 months.

More often the advice is to work fresh manure into the ground 3 months before planting.

Standard procedure is to compost (hot or cold) for 6 months before use, or to incorporate it into the soil in the fall.

[Jeff Layman]

Depends which E. coli you are talking about. Many strains are highly pathogenic; I wouldn't like 0157 in me, for example, immunosuppressed or not. More info here if you don't mind being too bored:

[Stephen Henning]

If there is nothing to kill off, then why worry. Many compost heaps have diseased plant material that can harm plants. There is a concern then. But non-caninvore and non-omnivore waste is not a major concern.

The hydrogen sulfide, methane, ammonia, and carbon dioxide given off by fresh manure are concerns in hot or cold compost heaps. Horse manure is a solid waste excluded from federal regulation because it neither contains significant amounts of listed hazardous components, nor exhibits hazardous properties. C. tetani is reportedly found in equine manure, but does not represent a source of significant public health risk. Many common equine helminths (worms, bots, etc.) are pathogenic to domestic animals but are not pathogenic to man. Generally speaking, horse guts do not contain the 120 viruses and constituents of concern in human, dog and cat feces (carnivores and omnivores). Most viruses with zoonotic potential (animals infecting humans) are not found in horse wastes.

Pathogens of primary concern are waterborne microorganisms that usually follow ingestion pathways into the body. Transmission can also occur through direct oral-fecal exposure. These include Cryptosporidium parvum , Giardia duodenalis, Campylocbacter spp, Salmonella spp., pathogenic strains of E. coli, andYersinia spp. By far, C. parvum and Giardia are the two of most concern because they have very low thresholds of infectious dose. People infected by these organisms may exhibit a range of symptoms from mild abdominal discomfort to death, especially among the very young, elderly, and people with immunologically suppressed systems. Neither of these organisms can be destroyed easily with traditional water treatment processes.

So if you use horse manure, make sure the people that gathered it washed their hands after using a toilet. They and their pets are much more of a concern than the horse manure itself.

[nmm1]

I wouldn't worry about 0157 - indeed, I may have it, for all I know to the contrary - as it is dangerous only to the very young, very old and immunosuppressed. If you look at the reference you gave, most of the pathogenic forms are described as dangerous to infants.

All forms (even the symbiotic ones) are dangerous if they grow in the wrong place, which is one of the reasons you need immunity to a wide range of them.

Regards, Nick Maclaren.

[someone]

Don't know anything about this hot or cold compost business. We don't even have a bin, just a compost heap at the back of our garden (it's sort of contained by two sides of a rotting fence and a neighbour's stone outhouse) and have been 'mining' this from the bottom for the last 25 years. We dig it out from the bottom, then riddle it through a garden sieve, and use it on our garden and allotments. Everything organic, such as meat and veg bits from the kitchen goes into it, as well as dead bodies of rats and mice our cats catch, and feathers of pheasants we find on the road and prepare for the table, and poo and stuff we find in the garden. Also any other unpleasant thing, like food that has gone off. We cover the top of the heap with grass cuttings when we mow the lawn, and just keep piling the stuff on. It seems to take about 3 years for the stuff at the top to de-percolate down to the bottom. We collect horse manure and pile it in heaps nearby and when it rots down enough we shovel it onto the garden and allotments.

I haven't heard of anyone getting sick from using home-made compost.

WARNING: over the last year or so, horse manure is to be avoided, because apparently horse owners and farmers are using a new toxic weedkiller which the horses ingest in the field when grazing, and it passes through their gut and if you use the manure, it will kill your plants off. I understand that this will be discussed on Friday in Gardener's Question Time, BBC4,

[David Hare-Scott]

Horse dung hot, horse dung cold, horse dung in the heap 9 weeks old.

I run horses and use their manure in the garden all the time. There are precious few if any pathogens in horse manure that will harm a human. I know people who spend their lives shovelling dung daily without a mask and it does them no harm.

Hot composting is to kill weed seeds, microorganisms are your friends.

David

[EastneyEnder]

At the risk of sounding like a nouveau Victor Meldrew, what's gone wrong with us?

I had my hands in fresh horse manure a few months ago when I helped a friend muck out his stables.

My dog was there and thoroughly enjoyed eating horse poo - don't ask

- it's a dog thing. I did try to stop him but that was only a bit more effective as stopping a gourmand access to free cakes and chocolate ;)

I'm up to date with tetanus and have been since about 5 years old. What's the problem? Anyone gardening should be... more likely to get it from soil than horses. Or rusty nails. Stood on them when I was a kid, and Kate Humble's older brother (yes, she of Springwatch) threw an electric fencing stake javelin-style at me by accident once and I still have the scar on my knee.

Immune systems need to be built up, or grown: you won't get one unless you do the work.