Manure: The Very Good
& The Downright Awful
Organic gardeners love manure; yet if you use it wrong, you may destroy all you’ve worked for.
I recently was e-mailed by a regular reader. She wrote:
“Hey David, have you done a post on the different types of manure yet?
The reason I asked is that I’m looking to grow my gardening area (the size) and was thinking about what type of compost/manures to add. I thought about your post about compost manure can be a concern and also from the ag county may have herbicide. I was also considering mushroom compost (mushroom farm nearby —) but read about the concerns of how the treat for bugs, etc.
So what did I come up with? Bunny poop! I found on craigslist two bunny poop suppliers here in — – woot! Very inexpensive, one is $3/50 lb size bag, other $12/50 lb bag (theirs is dried). Since I’m dumping on the ground as soon as I get bags, not worried about it being “wet”.
Also, I asked the Ag extension people and they said to not worry about herbicides in their compost, it’s all gone by the time it’s available.
Sooooo, with spring around the corner and warm crops needing to go in – if you haven’t done a manure article yet, you might want to consider it. I know I spent hours researching this and would have LOVED a simple article explaining all this! LOL Yeah, it’ all about me. :)”
“All about me” or not, it’s a good idea. So let’s do it.
The earth was designed to be a self-perpetuating system; many animals feed off plants… which in turn feed off animals, both on their manure and eventually on their bodies when they die.
As animals graze, they pick up plenty of nutrients and what they can’t use during the course of the day gets excreted. Both urine and manure are good for gardening but if you’ve ever tried to get a goat to pee into a mayonnaise jar, you know why farmers usually just collect manure for their plots. Using animal droppings for farming also makes sense because it closes the “nutrient loop” and reincorporates fertility into the soil, rather than disposing of it off site (city sewer engineers… I’m looking at you!).
For most of recorded history, man has used manure to nourish his crops. Unfortunately, that usage fell drastically with the advent of the tractor and the rise of chemical fertilization. It’s a lot easier to handle dry granules with perfect NPK ratios than it is to collect and distribute manure. On a small family farm, where you might have chickens, goats, a cow or even a horse, using manure is easy… but it’s not so easy on large farms that are growing monoculture crops without the use of animals.
Unlike chemical fertilizers, manure contains a broad range of nutrients. It also contains organic matter and a range of microorganisms that improve the tilth of the soil and its biodiversity.
My aunt, the most amazing gardener I know, once told me that she and my uncle had dropped a load of cow manure on their property and incorporated it into their gardens as needed. The surprising thing was that the place where they’d originally piled it up off the trailer remained green and lush for years after the manure had been used up. That’s good stuff.
This is where things get a little more complicated. The gardener has a variety of manures available for his fertilizing arsenal so one must ask what is the best manure for your garden. Some are usually too “hot” to use right away, like cow, bat or chicken wastes… others are filled with weed seed, like horse droppings… and others, like humanure, need to be handled carefully to avoid contact with pathogens.
The good news: composting fixes everything. If you’re not sure if manure will be too hot, compost it. Waiting will allow some of the nitrogen to dissipate and kill off pathogens. A few months is usually good enough, but if you’re paranoid, two years is the magic number in for complete safety.
Goat and rabbit manure are super-special because you can apply them directly to the garden without having to worry about burning your plants. In fact, the gal who wrote me was lucky to get “bunny poop,” since that’s one of the highest quality droppings you’ll find anywhere.
Though chicken manure sometimes gets a bad rap for being a garden killer, I’ve found that side-dressing plants with a dusting of dry chicken manure works well. Just go light – I went a little nuts one year and roasted some of my kale. If your plants turn yellow and brown, then you’re doing it wrong.
For my field corn, I put a couple shovelfuls of chicken manure into the bottom of a 55 gallon drum, then fill 2/3rds full of water. Every time I visited my field – about every two weeks or so – I’d stir the amazing-smelling slop and then fill a couple of cheap watering cans (with the nozzle roses removed) and walk along the corn rows letting the manure water stream out. This works wonders.
Whatever manure you have access to, chances are there’s a use for it in your garden… unless… well, you’d better just keep reading.
The Bad News On Manure
I used to work at an advertising agency back before I discovered how great it was to own my own business.
One day my friend Will and I were talking about some scandal in which yet another respected leader was caught directly lying. After a few years of writing advertising and hearing how salespeople and marketers would toss the truth out in a heartbeat, we were both pretty fed up with fake… and this was a crystallizing moment.
Will shook his head and muttered to himself.
“Everything is bulls—. Everything.”
He looked up at me, eyes blazing with sudden insight, his face suddenly reminiscent of an ancient mystic or half-starved monk.
“It’s true, isn’t it? Everything is bulls—!”
Unfortunately, in this fallen world, that’s basically true. Yet unlike cow manure, the “bull” we’re subjected to on a daily basis isn’t even useful for fertilizing.
Enough philosophizing. So why do I bring this conversation up? Because manure from off your farm (and probably on as well, unless you’re being very careful) is likely to be contaminated with a variety of nasty things you don’t want in your garden.
It’s ironic that the excrement itself is the least offensive part of manure… but there you go.
What contaminants? Try these on for size:
1. Heavy metals
There’s arsenic in some factory chicken feed. There’s also a variety of other heavy metals that are in a lot of commercially produced composts, thanks to “green” composting programs that recycle sewer sludge into fertilizer. Though on its surface, it seems like a great idea, the reality is that a lot of pollutants end up in the sewers. If you buy “Milorganite” or any number of other bagged composts or fertilizers, you could be adding a nice dose of poison to your soil.
Animals are given a wide range of drugs, some of which fail to break down quickly and are passed into the animal’s waste. You probably don’t want these in your garden.
Oh yes, let’s not forget these. Fields are sprayed with a bunch of junk to kill pests. Some of these fields are growing crops that are then fed to animals… and, you guessed it… it comes on through.
Now this isn’t cool. The soil relies on an intricate balance of competing and cooperating species… when you dump antibiotics into the ground, you kill off some organisms and pave the way for others to become dominant. You also increase the chances of “superbugs” arriving through adaptation to the toxic conditions. Since a lot of animals are kept in tight quarters under harsh conditions, massive amounts of antibiotics are given to them… and they come on through.
This set of chemicals will produce the most drastic effects. They can literally destroy your entire garden in days… and they’re now everywhere. Thanks to Ag. Extensions and their unholy alliance with companies like Dow AgroSciences, herbicides are regularly recommended and applied to fields where animals graze. A couple of years ago I had a brutal run-in with aminopyralids that toasted my garden beds one year and killed or stunted many of the young trees and bushes in my food forest. In fact, that experience turned me into a garden writer, rather than just a gardener.
Farmers spray these herbicides to kill plants like pigweed and blackberries in their fields without harming the grass. Unfortunately, they stick around for a long, long time… many times for years. The animals eat the grass and the herbicide passes into the manure. Then we use the manure on our gardens… and everything dies. Even after composting for a year the manure will still kill your garden.
This is absolute madness.
At the top, my friend wrote this:
“Also, I asked the Ag extension people and they said to not worry about herbicides in their compost, it’s all gone by the time it’s available.”
That’s not true at all. I responded to her with this:
“DO NOT trust the Ag extension. They’re totally wrong. Some of these toxins can and do persist in manure for up to 5 years. Remember: they are a distribution point for information that sells product… when I first wrote on the problem in my garden for them, they wouldn’t allow me to mention companies or brand names, even though the info is out there. Just one of the reasons I dropped my Master Gardener title.”
Unfortunately, most of the manure stream has been poisoned with these chemicals at this point.
How To Make Sure Manure Won’t Kill You And/Or Your Garden
It’s a bummer way to end this article, but here’s my recommendation – don’t import manure for your garden if:
1. The farm isn’t organic
2. The animals are eating imported feed/hay or living in imported bedding straw
3. The animals are treated with chemical de-wormers/antibiotics/etc.
4. The bagged manure contains “biosolids”
As you’ll quickly see from that list – it’s basically impossible to meet those criteria. Yet if you don’t, you’re running the risk of poisoning your ground. It’s just not safe to add manure anymore unless you KNOW KNOW KNOW it’s safe.
The best bet is to raise your own animals and use their manure… or use your own manure (but that’s a topic for another day).
Manure is indeed one of the best fertilizers for your garden.