Charlie Heasman; 7th June 2019


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Skerries allotments, May 2019


Tomato plant showing classic symptoms

When I first started writing this blog I thought I’d be talking about growing healthy veg, working with nature and all things joyous.  Now, for the second time in three months, I’m writing about something nasty.

You may recall that in April the subject was the huge amount of waste we allotment holders collectively produce, the illegal dumping of it, and the problems and expense of dealing with the consequences of same.  I’ve a feeling that we have not seen the end of all this and that another rant may not be too far ahead in the future.

But that’s another day’s work;  here and now I want to alert everyone to the dangers of herbicide contamination which can, and is, finding its way in to our allotments wreaking absolute havoc as it does so.

The problem is aminopyralid poisoning, and it’s on the increase.  None of us can afford to ignore it or pretend it doesn’t exist.  It does, and it’s only going to get worse.

The problem, at least in our plot, first appeared last Spring and initially we had no idea what was wrong.  Our tomatoes were the first to show signs, with the growing tips curling into tight gnarled knots, the stems growing long and spindly so that they couldn’t support their own weight, and further growth ceasing altogether.  Symptoms, in short, identical to those in the photos above.  Not ours, incidentally; those are this year’s plants and someone else is the lucky owner.

At first we thought it must be some sort of virus, though what and where it had come from we had no idea.

Then other things started happening.  Perfectly healthy broad beans – raised in modules in the polytunnel –  were planted out, sat in the ground for a week or two, tried to flower when only six inches tall, and died.  A row of peas was perfectly healthy and growing well for most of its length, but at one end seedlings died faster than we could replace them.  All other veg seemed pretty much okay.

If this was a virus it was acting in a very strange manner indeed.

At the same time our friend Carmel, who has two plots in two different parts of the allotments was having identical problems not only with her tomatoes but also with her potatoes: all showing exactly the same leaf curl symptoms.  This was a little surprising because our potatoes were perfectly fine.

The penny finally dropped: we had both used the same batch of cow manure.

One further piece of evidence was an absolute clincher as far as we were concerned.  I had spread manure on most (but not all) of the allotment and nearly all of the polytunnel.  In fact I ran out three quarters of the way up the second bed of the tunnel and applied compost instead.  The tomatoes planted here were perfectly healthy, showing no signs of stress and stayed that way for the summer.  All the rest we had to take out and replace with fresh plants, this time grown in grow bags.

Ditto the peas, which had also received compost except, as you might by now have guessed, one end which did get manure.  Entirely by accident, and nothing to do with judgement, our potatoes didn’t get manure either.  And stayed healthy.

We now needed absolutely no more convincing that the cow muck was in some way to blame.  But how?

At this point I did what I invariably do when I’m stumped: I Googled it.  The answer came up time and time again: aminopyralid.  Try it yourself, there’s an ever increasing amount of information out there – most of it, significantly, from organic growers and gardeners.

In fact all of a sudden everyone seems to be waking up to and talking about the dangers.  Here in Ireland Klaus Laitenberger from Green Vegetable Seeds talks about it in his June newsletter and over in Somerset organic grower and gardening guru Charles Dowding posted a Youtube video two weeks ago.

For my part, I was going to say nothing just yet because I recently started doing a trial and wanted to see the full results before saying anything.  But fresh outbreaks are occurring almost weekly in Skerries allotments and it would be pretty useless to wait and warn people after the event.  In any case, I have some results already and am about to share them here.

I kicked myself last year for not retaining a sample of the suspect manure for laboratory testing, which I thought would have settled the matter one way or another.  (Some people were still insisting that the cause was a virus; others blamed late frost, nitrogen excess and anything else they could think of).

In fact lab testing is not an option here, mostly because it is prohibitively expensive.  There probably isn’t a facility in Ireland anyway; samples would have to be sent to England or beyond.  The problem is that aminopyralid can cause damage even when present in minute quantities, 1 part per billion will destroy sensitive crops such as tomatoes, potatoes and legumes, and 1 part per billion takes a lot of finding in even the most advanced laboratory.

So I had nothing to send for testing and wouldn’t have been able to afford to do so in any case.

Then, at the beginning of last month, I heard that someone elsewhere in the allotments had spread cowmuck over almost his entire plot and planted potatoes, with disastrous results.  I don’t know the guy, I’ve never met him, but I can quite confidently tell him that he has aminopyralite contamination.  I might never meet him anyway because I’m told that at this point he walked out, shut the gate, and vowed never to return.  Shame.

But at least he’d left the remnants of his manure pile behind, so I helped myself to a bucketful.  Back in our allotment I took soil from a bed that I knew to be clean and filled flowerpots with a 4:1 mix of earth and cowmuck.  Soil was taken from the same spot, mixed 4:1 with compost and also potted up, the pots were labelled.  Pea plants and two tomato plants went into each sample, were given the same subsequent treatment and kept side by side to see what transpired.

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21st May, peas and tomatoes potted up.


Peas two weeks later (compost on left, cowmuck on right)


And the tomatoes

To my mind the evidence is irrefutable, but as a backup I subsequently planted a couple more tomatoes, french beans and four potatoes.  These are not ready yet but I’m confidently predicting the outcome.

This might prove there’s something wrong with the cowmuck, but of course it doesn’t prove what exactly.  For this we must revert to the internet, as said earlier.  Google aminopyralid images and see what you get; you’ll get pictures like these.  Search for written texts or videos and you’ll get the same story.

So what is this aminopyralite, and what’s the story?

It is a herbicide manufactured by Dow Chemicals and is licensed here for the control of broadleaved weeds in agricultural grassland and has been around for the last decade or so.  On this side of the Atlantic it is most commonly sold under the name of Forefront; in America as Grazeon.  In 2014, after much controversy, it was withdrawn from the market here (at least in the UK; I’m not altogether sure about Ireland) and that should have been the end of it.  But in 2015 it was reintroduced with exactly the same formula and the only difference being enhanced safety guidelines on the packaging.  One of those guidelines was that users should ensure that treated grass or hay should not be allowed to enter the compost chain.

Clearly this is not working.

Aminopyralid is absorbed by all the vegetation it is sprayed on.  Broadleaf weeds die; grasses do not.  But those grasses retain the chemical and one way or another (as grass, hay or silage) are eaten by cattle, sheep or horses, pass through them and end up in the manure.

It will eventually break down but no two authorities can agree on how long this will take.  Estimates range from one year to five.  I hope to prove here that one year is hopelessly optimistic.  Back to Carmel.

Last year she carefully took all of the cowmuck that she could back out of her beds; a laborious process as one can imagine.  Also, by the very nature of things, inexact.  This year she rather foolishly planted her tomatoes in the same place – she won’t mind me saying so because she’s kicking herself anyway – and got the same results.  Those are her tomatoes in the first two photos.

So that batch of manure at least has remained virulently active for two years so far despite Carmel’s best efforts to remove it.

Meanwhile another grower is experiencing the problem in his polytunnel this year for the first time.  Again, reef everything out and replant in growbags.  He is not best pleased either.

At this point I should stress, very clearly, that I am not blaming any individual for the problem in our allotments.  I’ve been told the name of the farmer from whom the manure came, but I’ve never met him.  Those who have tell me that he is a conscientious type who adopts best farming practices and would be appalled by all this, and I have no reason to disbelieve it.

Which leaves the question hanging in the air: where did the contamination come from?

I’m also told that he buys in some of the winter fodder for his cattle, and it is entirely possible he bought the problem in completely unwittingly on a contaminated delivery of hay.  This is the crux of the problem: the stuff is so insidious, persistent and invisible that it is virtually impossible to avoid it.  As if to prove the point, yet another allotment holder this year bought in horse manure, from an entirely different source, and is experiencing exactly the same problems.

So what can we do?

Apart from call for the stuff to be banned, which we should, the short and rather glib answer is to be very careful.  Klaus makes an eloquent point in his blog when he calls gardeners “the canaries in the coalmine” (or was it Michael D Higgins who said it first?).  It’s bitterly ironic that organic growers are the ones hardest hit by malpractice or carelessness in modern conventional farming.  We are told that aminopyralite poses no risk to the human food chain but we can see that it can, and does, pass through livestock and poison future crops.  It would seem reasonable to question whether it is therefore present in the meat or milk.  We’re currently reassured that there’s nothing to worry about but we were told the same about thalidomide, DDT and a whole host of other things which were subsequently proven to be very bad indeed.

One thing we could do in the meantime is to stop using weedkillers ourselves.  Most in the allotments don’t anyway; a disappointingly large minority still do.  Perhaps if they come to realise that these sprays are not only bad for the environment but bad for themselves they will stop.

So, no sprays and no manure.  What’s next?  We have to get our fertilisers from somewhere, right?  Buying ready made proprietary brands of compost should be safe.

It should, but it still might not be so.

Manufacturers will go to great lengths to ensure that their supply chain is not contaminated – it’s in their best interests to do so –  but it can, and does occasionally, happen.  Levingtons, a name to be trusted, fell foul in 2016 when customers complained of failing crops.  In fairness to the company they admitted liability and ‘compensated’ the victims with replacement plants and suchlike; small comfort for anyone who’s just lost the best part of a season’s production.

       This from one anguished lady:

Jan H says:

12 June 2017

Levingtons are selling contaminated Grow Bags again this year. Ironically I bought 20 of their Grow Bags with vouchers that they gave me as part of my compensation for last years lost crop. I am now in the process of losing all my crops again except for those which I planted in my homemade compost which are all growing normally. I would urge anyone with twisted, distorted and deformed plants to shout about it. How do we get this stopped? We are being sold poisonous compost to grow our food in. Who in authority can put some weight to this and get it stopped? I am witnessing 5 months of work wasting away, all that labour and a lost crop again…….


Again, I’m not trying to victimise one particular company here; I picked Levingtons because they’re a reputable company and if it can happen to them it can happen to others.  And it has happened to others.

A small bit of good news, but only a small bit: there is a test you can do – as

recommended by the RHS – on your freshly acquired manure or compost.

Before using it take a sample and plant a bean.  If after two weeks the bean is growing and healthy you’re good; if it crunches up and dies you’ve got a bad batch.  The trouble is that you’ve just wasted two weeks and have a ton of useless manure on your hands.  How do you dispose of it?

You can hardly take it home and put it in your brown bin, for all sorts of reasons.  You could  spread it on grass but the only grass you’ve got is in the laneway outside your allotment and your neighbours aren’t going to thank you for that.  You’re stuck with it.

The only answer is to keep things as ‘in house’ as possible, make your own compost from your own allotment and be very cautious about importing anything – anything at all.

Even garden waste can be problematic.  It turns out that aminopyralite has a cousin called clopyralid (thank you again Dow) which is a weedkiller approved for use on lawns.  It has a similar chemical composition and does the same things.  So if a few bags of grass clippings come your way, check and make sure the grass in question has not been sprayed, it might well have been and you will have just brought in exactly the same problems you’re trying to avoid.

All of which sounds incredibly depressing, and I’m sorry if it does but facts are facts and we ignore them at our peril.  Perhaps it’s time to stand up and shout about what’s going on around us.

Despite all this there are still people with perfectly healthy allotments, just make sure you’re one of them.