Aminopyralid: we need to stop this!

Aminopyralid contamination of home gardens and allotments is back. Every day I am hearing of new cases of carefully nurtured crops maimed and wiped out by this dreadful chemical. I’m not an alarmist sort of person but this is totally avoidable and – what makes it even worse – this is not the first time that aminopyralid has been responsible for widespread contamination of our plots.

If you suspect aminopyralid contamination, report it to Corteva here.

What is this chemical, how is it spreading and what can we do?

It is really sad. Small scale growers, home gardeners and allotmenteers all doing what they feel is the right thing, growing as naturally as they can and using local resources to make their compost or buying from trusted garden companies, are unknowingly introducing this hormone mimicking herbicide to their plots. Just the tiniest trace can contaminate, harming and killing peas, beans, tomatoes, potatoes, lettuce, spinach, Jerusalem artichokes and peppers, plus many kinds of flowers too.

Sorry to write a gloomy post – I don’t have it myself, these photos are all from other gardens, but I think it is such an important issue.

Considering the number of people affected, more every day, the government and Dow are being rather quiet on the subject. So, many of us home growers, bloggers, social media users and You Tubers are coming together to do what we can to spread awareness of the problem and let fellow gardeners know what they can do to help.

Many don’t realise that they have it, blaming aphids, disease, weather or just bad luck.

Manufactured by Dow Chemicals, aminopyralid and clopyralid (a similar herbicide) are widely used by farmers to kill broadleaved weeds in grass and rape straw. As well as broad leaf weeds it kills poppies.

The agrochemical branch of Dow is also known as Corteva. Bizarrely they run something called The Environmental Respect Awards – astonishing “green was” from a company that manufactures and promotes these dreadful herbicides that are harming the gardens and allotments of regular folk. (The winners are not exactly what one would consider “environmental”).

Worryingly, it is also found in domestic herbicides for home use available in garden centres. This herbicide does not break down in the composting process and contamination is being reported in council composting systems.

Aminopyralid was approved for use in the UK in 2005, and I first heard about the terrible problems it can cause, destroying gardens and allotments, over a decade ago when news of distorted tomatoes, beans and potatoes spread from allotments to the RHS and into the media.  Use was suspended in 2008 when new rules were brought in, designed in theory to prevent the herbicide from entering domestic composting systems. The chemical passes through animals feeding on grass or hay and goes into their manure. It also remains in grass and hay that is composted.

The problem did not go away. In 2011 George Monbiot’s article explained some of the dreadful consequences of this herbicide and called for a suspension of sales. But that didn’t happen. It has continued to be a problem each year since then for some gardeners, usually brought in via horse manure, and we for the past decade we have been advising that people using horse manure check for aminopyralid (see bean test below) before using. However this year the cases of contamination have increased significantly.

In April Charles noticed that the broad beans on a small area of his garden were looking unhealthy: pale, weak and much smaller than neighbouring beans sown at the same time. Closer observation revealed the tell-tale deformed growing shoots: aminopyralid contamination.

The difference between this patch and their neighbours? The compost – here Charles had spread some homemade compost that had contained a small amount of manure and hay from the neighbours’ horses. He has been using their waste manure and bedding for seven years. Aminopyralid is so strong that even small amounts can contaminate.

The beans have now been replaced with sweetcorn, a relative of grass and therefore unaffected by the herbicide, to see what happens.

Here you can see the patch with the healthier beans growing alongside: healthy towards the front and rear of the photo.


And then almost daily we have been hearing of new cases, directly and via social media: a well respected gardener has had significant damage to her flower crops from contaminated compost, a visit to a newly established veg garden on a large estate showed distorted beans and peas, and comments in our no dig Facebook group as people anxiously put up photos of suffering veggies.

Other bloggers are writing about their experiences including Sustainable Skerries in Ireland who have experienced a terrible contamination.

Aminopyralid is turning up in some (not all!) horse manure, cow manure, chicken manure, small animal poo/bedding, green waste compost, straw, hay and grass (used to feed/bed animals and also on their own as mulches or compost ingredients) and in some branded composts from stores, so it is a potential problem for everyone even veganic  growers (until recently it seemed to be just a risk for people using manures).

Some people who have bought contaminated bagged and branded potting compost from shops and online retailers have been having the most awful experiences, even being threatened with legal action for complaining that the compost has caused problems (legal advice was taken and the brand can not sue). The same brand is mentioned in this RHS site from 2008. Others are being met with a wall of silence from the companies.

It is unlikely that the companies themselves knew that they were putting contaminated composts into their products – indeed it would be bizarre of them to do so. There is supposed to be a traceability, the treated grass (manure, etc) is not supposed to be entering the composting system, but it is and increasingly becoming more so. They probably had no idea that there was a risk.

Is it safe to eat plants grown in contaminated compost, or milk or meat from animals eating the grass and hay? Dow suggests “yes” as the trace will be small, but my opinion is that we really don’t know and back in 2008 (see the links in this blog post) Dow was advising people not to eat plants from contaminated soil. This would not be the first time that a large chemical company has assured us of the safety of their herbicide only for scientists to prove otherwise.

Has it been tested and declared safe for the food chain? I can’t find any evidence that it has.

The contaminated compost starts to break down in contact with soil bacteria, which is some good news for no dig gardeners as we certainly have plenty of healthy soil life (seems a bit unfair on soil bacteria to have to deal with this, though!) We don’t really know how long it takes, a couple of years at least is suggested.

Can you compost contaminated plant matter? We don’t know for sure, but for peace of mind make a separate compost heap and use that on shrubs or trees which won’t be affected by any residue.

Update for 2020 – sadly gardeners are once again reporting contamination including manures, shop bought composts (including veganic and peat free), mushroom compost and some liquid feeds. 

So what can we do?

There is a petition to get the chemical banned here. Write to Dow, your MP, the NFU, your newspaper, local press, favourite gardeners, the compost companies, ecological bodies and anyone else you can think of who can highlight the issue.

Check all composts before spreading and make as much as you can at home if possible. If you don’t have much now use alternatives such as comfrey and nettle feeds.

How to test for aminopyralid

Fill pots with composted manure (or whatever compost you are testing).  Have a couple of extra pots with “safe” compost in as a comparison. Sow beans (French beans or broad beans), peas or tomatoes and wait 2-3 weeks. If the compost is contaminated then you will see the distorted growing shoots develop.

Iain Tollhurst recommends using clover as it will show even the tiniest traces of aminopyralid (one part per billion) but we are not sure which would be faster to show the contamination.

34 thoughts on “Aminopyralid: we need to stop this!”

    1. Stephanie Hafferty

      I don’t have them I’m afraid and working all day today at BBC Gardeners World Live (2 no dig talks 🙂 ) but if I find out will post it here.

      Very good idea about a sample letter!

  1. Thank you so much for this information. I have now written to our local MP, asking for her to bring the matter up. It affected my crops this year, It’s horrific, very upsetting, and so frustrating that there is no one to turn to.

    1. Stephanie Hafferty

      It is frustrating that there is so much confusion about who to approach. I am so sorry to hear about your crops 🙁

    1. Stephanie Hafferty

      Thank you, I had a great day at GW Live. Looking forward to hearing some talks myself tomorrow 🙂

      Yes, it isn’t a good situation but I am optimistic that it will be sorted out.

  2. We have just spent hundreds of pounds on our new allotment and filled the beds with over 30 bags of “country organic natural stable manure” also mulched our much loved roses with it.
    Everything apart from the brassicas we have lost and are devastated. I sent pictures To Charles and he has confirmed it is Aminopyralid damage. We have 4 beds full of cabbages, kale, PSB and Brussels sprouts which have grown fine as it doesn’t “affect” brassica growth but now we don’t know if they are safe to eat? Would you eat them?
    Charles now has our evidence to add to the dossier, I have contacted the garden centre where we bought the stuff and I will be contacting Dow and my local MP.

    1. Stephanie Hafferty

      I saw the photos yes, so sorry for you. At the same time as reading this I have heard of another plot similarly contaminated with this very brand.

      I shouldn’t think anyone knows for sure whether it is safe to eat brassicas grown in the contaminated soil, the information out there is contradictory. One might imagine that it isn’t any worse than eating lunch in a regular restaurant where vegetables which are not organic are served, but I really don’t know. This chemical harms plants with the tiniest trace, so the actual contamination is likely to be quite small.

      Charles is growing sweetcorn in the bed where he had the contamination and he’ll eat those.

  3. Merle Threadgill

    Thank you so much Steph for the talk at gardeners world your last comment about the weed killer was a light bulb moment for me as I had the problem in 6 bags of wyevale compost I put in deep boxes in my greenhouse. In fIfty years of growing ve g Organically I had never seen anything like it . I have written to wyevale but they just don,t want to know I have asked them to test . I am the cook at our local lunch club and grow for them to keep the cost down and now will not have. Nearly enough veg for that as well as my own family . When I was growing organically commercially in Lincolnshire In the 1980s i was laughed a t but now the results are being seen so sad. Merle Threadgill

  4. Stephanie Hafferty

    That’s so frustrating 🙁 Do contact Corteva/Dow to report it. I will be updating the Aminopyralid post over the weekend with new information. We had a meeting with their representative this week and information from other gardeners has shown it to be far more widespread in bagged composts than we thought.

  5. I have it this year! I’ve written about it too…long sob story, and gloomy post, similar to yours, with a lot of the same facts too. I’m trying to get as much attention to it as I possibly can in our supposed GREEN New Zealand… 🙁 :'(

    I am heartbroken… first season in my brand new homestead potager (our first New Zealand home) ruined… my plans of selling my seedlings and produce to help with the family’s finances, and for me to grow the garden and my herb business… ruined.

    I don’t think they (the royal THEY) get how much this affects us “little” guys… It’s been a hard one for us! First we bought the soil (finances), now we can’t get from it what we wanted (loss of food security, income). And a heck of a lot of my resilience is going down the drain as I find more and more plants affected, and my garden, which used to be my LIFE and my ALL, is now a scary and sad place for me to go.

    1. Stephanie Hafferty

      Oh this is awful 🙁 I am so sorry to hear this, will look for your blog post.

      The only glimmer of hope is that it does gradually break down, so your garden will return to you – but not for a year or even more.

      This stuff simply shouldn’t be allowed to be sold.

  6. Pingback: Is my horse manure contaminated with aminopyralid? – Sahr O Fasuluku

    1. Stephanie Hafferty

      That’s awful Sahr. We are hearing so many more cases of aminopyralid and reports that its use is even more widespread, including on fields grazed by horses – even though it is not licensed for use with horses.

      People are reporting shop bought composts too with aminopyralid contamination. It’s terrible, really.

  7. Michelle Lotker

    Thank you so much for collating all of this information! We’re having a spree of this contamination in Durham, NC right now and it’s great to find so much information in one place.

    1. Stephanie Hafferty

      It’s awful, I am so sorry for you 🙁 We’re hearing about new cases every day

    2. Stephanie Hafferty

      Thank you – I wish we didn’t have to think about it. Hopefully it will be banned.

  8. I am in Colorado. I added some compost from a commercial “organic” firm to my garden and had what looks like herbicide damage. After a bio-assay showed the compost to be suspect, I sent the soil to a lab and for $300 it confirmed clopyralid contamination at 30 micrograms/kg (equivalently, 30 ppb by weight). I managed to push some of the plants through the damage by heavily fertilizing, including foliar application, but they are still not as happy as they would normally be. I also wonder whether it is safe to eat the produce. Any ideas on remediation?

    1. Stephanie Hafferty

      It’s an awful herbicide. I do not know if the produce grown in contaminated soil is safe to eat – there doesn’t seem to be anything conclusive either way.

      The soil life breaks down the contamination, it seems to take around 18 months.

      That chemical company has a lot to answer for, contaminating so many people’s gardens to make a profit…

      1. Not just the chemical company, but also the users who don’t inform anyone else that they have contaminated their manure. And “organic” compost companies that don’t have good source control. I am going to try activated charcoal powder and maybe bio-char. The raised bed soil gets replaced, but with what? What soil is safe? And a cubic yard of good planting mix is not cheap. As for eating — I don’t know. I have a question into the local extension about whether 30 ppb is something to worry about. I clearly is for plant health though. See this reference.

        It basically says that <1 ppb is not damaging to plants but 5 ppb will severely damage tomatoes.

        So much depends on whether I can get restitution from the company that sold it. With the lab test I at least will have a chance, and small claims court is always an option.

      2. Stephanie Hafferty

        The organic compost companies that I know who have been affected by AP are devastated by it. I think many people simply do not know the risks.

        Good luck with your claims. Unfortunately Corteva are still giving the impression that it isn’t a problem, yet it is even cropping up in liquid feeds

  9. Are there other chemicals which could contaminate FYM and produce the same effects? We have used wheat straw FYM composted for 4 years and this has caused what looks like herbicide residue damage on peas, beans and tomatoes this year. The same FYM is used on farms and could damage grassland especially species rich grassland.

    1. Stephanie Hafferty

      I don’t know – apart from clopyralid which is a “cousin” of aminopyralid.

      Ghastly stuff, and it is getting everywhere

    2. I had my compost tested after it ruined my garden. I used Anatek Labs in Idaho — I can vouch for them as far as customer service goes. I did the “persistent herbicide” screening (but call them first so that you get the right test for your situation). They tested for the following:

      2,4,5-TP (Silvex)
      DCPA (Acid Metabolites)

      I had high levels of Clopyralid but undetectable levels of everything else. Am treating the soil with activated charcoal. The garden recovered somewhat with a lot of fertilizing, including foliar spray of AgeOld brand liquid fertilizer. The testing was expensive ($300) but at least I know what is there and have a strategy to bring my garden back to health.

      A far simpler and less costly way is to do a “bio-assay” where you plant beans in a non-compost potting mix and a mixture of compost and potting mix BEFORE you add it to your soil. For me, that clearly showed that there was something wrong with the compost that was delivered — but I did it after the fact.

      BTW, the company that delivered the compost to me refunded the cost AND the testing cost.

      1. Stephanie Hafferty

        What a difficult situation for you. Look forward to hearing how it goes with the activated charcoal – best of luck!

  10. Aminopyralid and related herbicides are used to treat cereals as well as pastures so the route for contamination can be through the straw in the FYM as well as via animal dung who have eaten contaminated hay. Trezac is a product used on cereals such as wheat ad barley; it says on the label:
    • Do not use any plant material treated with TREZAC for composting or mulching.
    • Do not use manure from animals fed on crops treated with TREZAC for composting.
    But I suspect this is not always being followed as I think this is how my FYM has been contaminated.

  11. The situation is dire.
    I own horses and have veg crops.
    Years of weird growing symptoms in my plants and year after year of failing crops, scratching my head wondering what the hell is going on.
    Then i find out about ‘persistent herbicides’.

    Farmers are not telling buyers of their hay and straw theyve used this class of herbicides on their crops.
    Dow have legally protected themselves by changing the label on their products stating ‘not to be composted’.
    It’s taken me 4 months to finally get a reply what a major hay producer in the uk i buy as horse forage uses on their crops. Yes, persistent herbicides.
    They are not eager to tell anyone whats sprayed on their crops…like getting blood from a stone!

    The true cost of thousands of crops failing is unimaginable, due to this issue. I’ve had years of failed crops….it’s devastated my business…and my ‘organic’ farm.

    The real problem is you buy in hay from 1 supplier who uses aminopyralid, you put the dung on your manure pile – then another hay supplier uses clopyralid – that dung goes on the same pile – before you know it youve got a mix of concentrated herbicides in your dung pile – and i have documented proof of this: grass wont even go to seed in a hay field when this manure pile is spread on it. Even grass doesnt grow well or mature to seed with a mix of these chemicals in dung is applied as fertiliser.

    Wild plants, fungi are all wiped out.
    I’m in year 2 of no manure application and my crops are still affected, and i used just an inch of manure on crop bed soil, mixed-in, in year 1.

    Interestingly, to obtain organic status for any farm, agri-chemicals use has to cease for 3 years, the land rested for 3 years from chemical use – to begin to obtain an organic certificate.
    I’m experiencing that after next years crops, year 4 my soil will be free of contamination.

    The soil bacteria are amazing, but it takes time to break down these chemical structures that are man-made. With these chemicals not being organic molecular structures, even nature takes a while to figure out how to break them down.
    Nothing else breaks these herbicides down. Not UV rays from the sun, nor rain, nor freezing temps.
    I have a 7 yr old manure pile on my farm which i used last year, which killed all my crops! 7 yrs in a huge pile and just 1 part per billion of aminopyralid in that manure will kill plants! Just 1ppb!

    This has got to a level of chemical technology that akin to marginal ethics of cloning.
    Just because we can invent a thing, does that mean we should?

    Judging by the devastation many crop growers are experiencing with herbicide contamination, i think that question is answered.

    My farming livelihood has been utterly destroyed by this class of herbicides, as have many others around the globe, as this is global. Corteva/Dow are global suppliers of their chemicals.

    There are around 5 chemicals in the class of persistent herbicides routinely used by farmers/land management authorities. This is why municipal green waste systems are a source of contamination too. People spray their gardens. Councils spray the hedgerows/residential areas. The waste from these applications are municipal green waste stations and then bagged as ‘compost’.

    Aminopyralid has received most press, but dont be blinded that just 1 chemical is contaminating manure.

    What to do?
    Dont use any animal manure, unless you know the animal eats only organic food. In my country of ireland, rural farmers use clopyralid and aminopyralid so routinely its impossible to find forage not sprayed.
    If beds are already contaminated, mix the manure well with your soil. This enables more microbes to establish. Even no diggers can till the top 4 inches to mix. Water the soil so that the microbes have all they need to populate. The warmer summer temps will grow more microbes, they are more dormant in the winter.

    We can sue Corteva/farmers – thats a battle no-one wants to enter, but we may possibly end up there. However, its far more beneficial to be proactive. Spread the word. Buy only organic. Promote organic farming methods. Warn others of the herbicide contamination dangers.

    On a popular horse forum, many members talk of giving their horse manire to crop growing people and i warn them not to, unless they know for sure, no herbicide is sprayed. They disbelieve me when i say herbicides remain active in the manure and will kill plants! They think its impossible that such chemicals exist.
    Yes, its horrifying these are allowed to be used.

    These chemicals interfere with the hormone/endocrine system of the plant, disrupting its growth via disrupting the hormone system.
    1 study on equines has already linked metabolic disease/diabetes with ‘hormone disrupting agri-chemicals’ – and the future shall reveal the endocrine disorder epidemic suffered by humans and animals alike, are due to these hormone disrupting agricultural chemicals ubiquitously used throughout the world.
    If 1 part per billion kills a plant, what does 1ppb do in our body when we ingest food sprayed with these chemicals? Our endocrine system is far more complex than a plants. Fertility issues amongst young adults is epidemic. Diabetes/thyroid/menstrual issues dominate as ‘common’ human issues now.

    This class of herbicides was born due to the older chemicals needing 2 spray applications to kill ‘woodier’ weeds like docks/thistles/ragwort etc. Also rain washed it off, UV degraded the chemicals, something tougher was needed that was resistant to these old burdens of the older chemicals used.
    So another route of killing the plant was invented. Take down its hormone system. We require hormone signalling to grow, be healthy, regulate our bodies for health….so does a plant. Endocrine disrupting chemicals were therefore born. 1 spray and the job is done. No need to respray. Phew, that saved the farmers a job – so they were easy to market the product to. They ask no questions.

    Meanwhile humans and animals the world over have pituitary disorders, diabetes, cancers of endocrine glands, weight issues, coincidentally being more epidemic the more this class of herbicides is used around the world, on every major crop.

    Go organic – promote organic agriculture – it’s the only way out of this chemical ilness-ridden mess.

  12. Pingback: Herbicide Contaminated Compost, Straw and Organic Fertilizer - Garden Myths

  13. Is anyone in the UK government actually LISTENING to what’s being said in regard to these very damaging herbicides?
    After all; they’re not in the slightest necessary for hay, silage & other fodder production, as many field plants enhance, rather than detract from the nutritional value of the feed crop.

  14. Pingback: Aminopyralid — Humber Avenue Community Allotments

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