Beware: This Manure Will Destroy Your Garden

Last Updated January 26th, 2023 by David The Good 113 Comments

Manure is generally considered one of the best amendments you can add to your garden. At least it used to be. Here’s how manure in the garden may actually destroy your soil and plants for a long time.

This page may contain affiliate links. Please read my disclosure for more info.

The following article was written by David the Good of The Survival Gardener.

David and I first connected after he wrote an honest and thorough review of my book, ‘The Suburban Micro-Farm’, for Mother Earth News. David is an expert at home-scale food production and I was thrilled that he enjoyed it.

The truth is, herbicide-laced manure is a widespread problem that can completely destroy a garden, and David was one of the first to sound the alarm.

I’m grateful he’s sharing this information with us so that we may prevent this devastating and costly misfortune from occurring in our own gardens. — Amy

This Manure Will Destroy Your Garden!

Manure is rich in nitrogen, organic matter and a variety of minerals, adding nutrition and tilth to the soil and ensuring rich harvests of green and happy vegetables. It’s generally considered to be one of the best amendments you can add to your garden.

At least it used to be.

Now adding manure to your garden is playing Russian roulette with your plants. There’s a very good chance that it will completely destroy your beds and cause your plants to grow into twisted parodies of their proper growth pattern before dying ugly and unproductive deaths.

Here’s how.

A Load of Manure is a Gardener’s Paradise…Naturally

Some time back I did a very normal thing for an organic gardener: I bought a trailer of manure from a local dairy farm and had it dropped in my front yard.

I then proceeded to spread it across multiple beds, add it around the trees in my front yard food forest, and turn it into the ground along the front fence line where I was planting dozens of newly purchased thornless blackberries.

Read more about creating food forests.

A few weeks later, I planted my gardens – and everything started going very, very wrong. My transplanted tomatoes and eggplants started to twist up. They were still green, but their leaves were thick and curled and the amount of new growth was much smaller than it should have been.

Something was very wrong.

My thought upon seeing the weird growth in my tomatoes and eggplants was that I was dealing with a virus. They were both Solanaceae family – maybe it was some weird and horrible disease I’d never seen before?

Then some of the edges of the blackberry leaves started twisting and turning brown. A virus wouldn’t jump families – blackberries are Rosaceae! I had to look elsewhere.

I noticed the blackberry leaves were deep green, despite their strange growth. Perhaps there was too much nitrogen in the manure?

The manure had been composted for over six months, according to the farmer. And it certainly didn’t look or smell fresh. It was earthy and crumbly, well-aged stuff. It looked just like something you’d want to add to your garden.

Then the mulberry tree started looking weird. And the pecan trees and the olive exhibited the same symptoms.

Would you like to grow more food with less effort? Check out my mini guide, The Permaculture Inspired Vegetable Garden.

That Herbicide is Poison

From my reading, it wasn’t too much nitrogen. The symptoms were too strange. And it wasn’t a virus.

The only thing in common between all these sick plants was one big load of manure.

I called the local master gardeners and shared the symptoms and they had nothing helpful to suggest, so I started searching on my own, looking up phrases like “twisting leaves manure,” until I came across an article about a community garden disaster on the left coast.

They had purchased a load of manure compost, then lost many of their plants because of a recently released herbicide designed for hay growers and cattle farmers.

Aminopyralid.

I had met my nemesis.

I called the farmer who had sold me the manure and asked him if he’d sprayed anything on his hay fields. He told me he had tried a new product recommended by the University of Florida for the elimination of spiny pigweed, an obnoxious recurring weed in his pastures. “It worked really well,” he told me.

I shared that all my plants were dying and asked if he could find out what he’d sprayed. I was pretty sure I knew already, but when he sent me a picture of the label, I knew for sure.

It was Grazon, an aminopyralid-based toxin from Dow AgroSciences.

Herbicide Damage -Eggplant. Image by David The Good.

Contaminated compost: aminopyralid effect on tomatoes. Photo by Karen Land.

Grazon Damage. Image by Luzette of Buffalo Girl Soaps.

Toxic Manure in the Garden is No Joke

The farmer was quite upset by my report. He had sprayed his pasture the previous summer. That was about nine months before I called him, and he was told Grazon was safe for animals to consume.

Armed with my new research, I shared that the toxin could continue killing plants for years, even after being eaten by animals, then excreted, then composted for months.

He refunded the $60 I’d spent for the manure and apologized, telling me he wouldn’t spray again and that he had a lot of people that bought his manure.

I didn’t blame him for the mistake and I didn’t ask for his help replacing the thousand dollars or so of destroyed produce and perennials. We all make mistakes and he seemed like a decent guy.

I reserved my blame instead for the University of Florida, Dow AgroSciences and the government that lets these poisons into our gardens.

By the time I knew what was going on, I had lost the first half of the growing season. Most of my garden beds were loaded with this manure – and my poor blackberries were twisted and dying, along with multiple fruit trees.

Tired of generic permaculture design advice that you can’t apply to your specific goals? If so, check out my Permaculture Design Program and get the tools and support needed to create and implement your own permaculture design.

This situation is bad manure, and gardeners everywhere need to be warned!

I was angry and feeling sick over the whole thing, so I called my friend Carolyn who owned the local Natural Awakenings magazine and asked if I could write an article warning other gardeners about the new danger of using manure in the garden.

She agreed, and that led to me being contacted by Mother Earth News and becoming a blogger with them. Eventually, the manure fiasco led to me dedicating myself to making all my own compost – and that led to my book Compost Everything: The Good Guide to Extreme Composting.

My manure-in-the-garden fiasco ended up launching my writing career. God works in mysterious ways. My terrible year of poisoned gardens ended up saving a lot of other people’s gardens – or helping them figure out what happened after a poisoning event.

Person after person has written me to share tales of wrecked gardens. Some people lost beds because of contaminated hay they used in their compost. Others lost beds due to manure. Still others purchased compost or garden soil and had it kill their plants.

Aminopyralids and other persistent herbicides are all over the place now and it’s a minefield for gardeners.

New gardeners are really in a bad place now, as they often don’t know what to expect from their plants. When Aminopyralid symptoms strike, they just assume they made a mistake, not that their beds were poisoned.

Here’s how to keep your gardens safe.

1. Don’t purchase compost.

Many facilities still don’t have proper safeguards in place to keep their product uncontaminated.

As a matter of fact, herbicides can contaminate commercially made soils that are approved for Organic agriculture! Learn 5 essential questions to ask a producer before buying compost soil for your garden.

2. Don’t use manure from grazing animals.

That neighbor offering you well-rotted horse manure? A decade ago I would have said, “Great!” Now I would say, “Absolutely not!”.

Despite it being a “free” garden amendment, horse manure tends to be the most concentrated source of contamination.

Here’s why:

Imagine that a horse pasture is sprayed with Aminopyralids to rid it of broadleaf weeds. The hay eaten by the horses is also sprayed, as well as the straw used for bedding.

That’s three sources of contamination. What’s more, the herbicide becomes concentrated in the manure. So it’s easy to see how horse manure is one of the worst offenders.

But don’t be tempted to think that because you only have one source of herbicide, say, contaminated grass clippings from a neighbor or conventional straw for mulch, that your compost soil is safer. It’s hard to predict herbicide concentration.

Though your neighbor might not spray his fields, he likely buys hay – and a lot of hayfields are now sprayed. It happens again and again and again. I have heard reports that even store-bought bagged manure is killing gardens.

Just say no to manure in the garden from grazing animals.

Remember, though, that Grazon is used to kill broadleaf weeds in hay. If you can get manure from non-grazing animals, it should be fine. Chickens and rabbits should be okay, unless you use straw or hay as bedding. Rabbits may eat a little grass but they are usually fed with alfalfa pellets and alfalfa is not sprayed with Aminopyralids.

3. Avoid hay and straw in your compost or as mulch.

A friend lost a chunk of her food forest plants after picking up a load of well-rotted hay and spreading it around. Members of the grass family may be sprayed with Aminopyralid-containing pesticides. Avoid.

Here’s more about keeping persistent herbicides out of your compost bin.

4. Make your own compost.

Learn to compost everything. Fall leaves, shredded paper, fish guts, eggshells, lasagna – whatever. The more organic material you can add to your compost pile and eventually to your gardens, the less you need to buy to amend your gardens.

Make a worm bin for composting food scraps.

I compost all kitchen scraps, including meat. Gather lots of leaves or grass clippings from your (unsprayed!) yard and throw them over stuff that might stink. You can also cover your bin to keep out vermin. Nature will do the rest. It’s just a matter of time, not perfection.

This isn’t an easy time to be a gardener. The world is toxic and there are plenty of pitfalls, including the use of manure as an amendment.

I’m not exaggerating when I say this is a widespread problem. It’s no longer a good idea to add manure to your garden. If you do, you’re running a big risk and can destroy your plants because someone sprayed toxins on a field somewhere far from your garden.

It’s not easy to find good alternatives, but it needs to be done. Watch your back and start making your own compost. It may save you some serious heartache.

Get David’s tips for:

A Note from Amy

It’s important to support your local farmers who commit to doing honest and good work. If you have a farmer who has been supplying you with material such as manure, hay, straw, or compost, then I encourage you to start a conversation about herbicide contamination.

Ask questions. Learn about their process. If they have control over all of the materials in the supply chain and emphatically say they do not spray, then they deserve to have your business.

If the farmer outsources any of those materials (hay, straw, or animal feed?), it’s more difficult to know for sure. Ask for the contact info of their supplier. Ask more hard questions. Go with your gut. Don’t assume that all farmers are dishonest, because that is certainly not the case, but obviously you want to be cautious.

Farmers are busy. When their extension office tells them a widely used (herbicide) product is safe, they may go with it, having no idea of its wrath.

Have you suffered problems due to herbicide-laced manure in the garden? What changes will you make to your gardening routine to avoid it?

About the Author

David The Good is the author of multiple gardening books including Compost Everything: The Good Guide to Extreme Composting, Totally Crazy Easy Florida Gardening, Grow or Die: The Good Guide to Survival Gardening and his latest release Turned Earth: A Jack Broccoli Novel, the world’s first gardening thriller.

David has been featured in Mother Earth News, Backwoods Home, Heirloom Gardener Magazine, The Grow Network and other outlets. He is also the creator of TheSurvivalGardener.com. David currently lives with his wife Rachel and their children somewhere in Central America where they collect rare edible plants and enjoy growing everything from ackee to yams.

Read Next:

>>> Get my free 19-page Guide to Organic Soil Amendments for more ideas:

« 7 Wild Herbs for Growing Your Own Pharmacy

Year-Round Gardening: It’s Easier Than You Think »