Contaminated manure: the bad smell lingers

by Charlie Peverett in At home on 29.09.08

In July, we reported on how veg growers across the country have had their crops ruined by ‘bad’ manure.

The most likely cause is aminopyralid, a hormone-based weedkiller that is used on grassland. It appears to have found its way through horses’ digestive systems into manure and onto people’s allotments and gardens. [*UPDATE*: it's been pointed out that cows' manure and straw used for animal bedding might contain residues too.]

In July, aminopyralid was temporarily withdrawn from use at the request of its manufacturer Dow AgroSciences. The firm is investigating whether inappropriate agricultural use of the herbicides containing aminopyralid is to blame.

Meanwhile, the Pesticides Safety Directorate has recently confirmed that it believes eating veg grown in the contaminated manure “does not have implications for human health”. Which is welcome.

But for a lot of people, their veg didn’t even grow, not allowing them the luxury of making a decision whether to eat their own produce.

And not even ‘organic’ growers were exempt - because you can grow organically under Soil Association rules and still use manure from sources where the horses have been fed on non-organic grass.

Life in the Green Lane

The Royal Horticultural Society says it has been receiving about 20 calls a week since Christmas, and reckons that several thousand people are likely to have been affected across the country.

One of the most vocal critics of what’s happened is Sue Garrett, chair of the Green Lane Allotments in Horbury, West Yorkshire. She’s been able to see what’s happening across a number of plots, and says she is disappointed by the lack of publicity for something that has affected so many people.

She describes all kinds of damage attributed to weedkiller contamination by allotment-holders: a polytunnel of tomatoes ruined for one grower; a family new to the site who were put off feeding their children from the plot after they heard about the problem, and have hardly been back since.

Some of the effects have now eased - potatoes in particular appeared to bounce back.

But Sue’s worried that for some plants and growers there may be further trouble, and that although there has been a temporary suspension of the chemical’s use, it could be reapproved with different guidelines, with no guarantee that it wouldn’t happen again.

“Even if it isn’t reinstated, this stuff’s out there in the supply chain now - people could fall foul of it for the next couple of years or so, and they need to know it’s there.”

The issue has had some media attention - notably in The Obsever at the end of June, and when Sue appeared herself on BBC2’s Gardener’s World in August - but Sue is worried that it not enough people understand that it might affect them.

“In a way, it wasn’t taken as seriously as it could have been… [especially] by people who may be quite happy to use chemicals but wouldn’t use them if they thought that they were going to kill their crops.”

She for one is not ‘fanatical’ about growing organically. While she tends to avoid spraying manufactured chemicals, she says she does use them occasionally (for example, to prevent blight).

But she says that this episode has made her think again about the kinds of chemicals that find their way into the food chain. “It makes you wonder what you’re eating,” she says.

The manure they got was from a local supplier, who had apparently bought silage in to feed his horses. Sue says that they won’t be taking manure again, from that supplier or anyone else, while it’s so difficult to be sure of its provenance.

And it’s not just manure that’s starting to look suspect.

“How safe are we buying compost?” she asks. “How safe are we buying manure substitute that you get from garden centres? You can’t look at a bag and say, ‘well it’s organic so it’s ok’, because people have emailed us to say that they suspect contamination has come through organic materials.”

For now, she says that allotmentholders are using their own compost (of which they don’t have nearly enough) and the old stalwart, fish blood and bone.

They’re not going to be only ones. As Emma Townshend wrote in the Independent over the weekend, “my solution this year is going to be chicken pellets, and I’ll go back to spreading manure when I know exactly where it’s been.”

How long will that be?

Well, arguably until the powers-that-be get together a more robust framework for ensuring that garden products are better protected in future.

Which at the moment looks like a more remote prospect than that of piles of unwanted manure rotting away in stable yards across the country.

Think your garden or allotment might have been affected by hormone-based weedkiller? See the RHS weedkiller advice pages for more information.

Top two images used with by permission of Flickr user Greenfingers41, bottom picture by Flickr user normanack.