Weedkiller in manure: update

by Jane Moore

It's this time of year when the allotments become a frenzy of activity. Everyone is digging, composting and manuring like mad.

Adding manure to a trench before planting.It's this time of year when the allotments become a frenzy of activity. Everyone is digging, composting and manuring like mad. My neighbours Mr and Mrs Ron wait until Easter, then till and plant their three plots within a week. The rest of us just do a bit here and there.

But this year a fretful question hangs over the quality of manure. Some anxious comments have been posted on my blog about last year's contamination and subsequent crop failures. The manure was contaminated with the herbicide aminopyralid, which distorted and sometimes killed crops. Plants most affected included potatoes and tomatoes, peas and beans, carrots and lettuce. Aminopyralid is slow to break down, so it seems likely that it could cause problems for some years.

So, to give you an update:

There is still the potential for manure to be contaminated this year. If you're wary of applying muck to your plot, speak to the farmer who supplied it and send it back if necessary. Contaminated muck can be spread on grassland.

Products containing aminopyralid have been withdrawn from supply, sale and use while the Pesticides Safety Directorate investigates its potency. However , it's not illegal to store the herbicide, so there's no guarantee the farm where you source your manure has not been using aminopyralid.

Dow AgroScience, which makes aminopyralid-based products such as Forefront, is offering advice to gardeners and allotment holders via the email address ukhotline@dow.com. Information collated by the manufacturers will be passed to the Pesticide Safety Directorate.

In short, be cautious. Be careful of accepting manure from sources that cannot give assurances that it hasn't come from animals fed on grass or forage treated with persistent hormonal weedkillers.

But please don't stop using mulches and organic matter. Returning nutrients to the soil is vital for healthy plant growth and decent yields, improving soil structure and moisture retention. If in doubt, stick to home-made garden compost, leaf mould or composted green waste from the local council.

Discuss this blog post

Talkback: Weedkiller in manure: update
Your comment will appear after a quick registration step

Gardeners' World Web User 28/02/2009 at 00:55

I struggle to mke enough compost. NO matter how much I put in the bins it rots down to virtually nothing. I know this is general but it never ceases to amaze me how little compost we get from a huge bin of debris! I have a stable nearby and can get free muck from them. Is it safe? But I have no car so have to walk down the North Circular in London with a wheelbarrow full of horse poo. Not cool ;)

Gardeners' World Web User 28/02/2009 at 20:49

I did buy manure from the garden center last year, when I heard the stories of contamination I was frightened to use it so it has been stored at the end of the garden ever since, I think may be it is OK! to use although I would be very upset if it polluted my garden. I also wonder about council compost as I have seen some of the sruff that people put into the green waste skips, like some of the perenial weeds and I have had my garden badly infected with chickweed and many other very difficult weeds to get rid of.

Gardeners' World Web User 01/03/2009 at 11:25

I was affected last year by weedkiller in manure which I purchased from a garden centre. I lost my tomatoes and had to completely dig out the bed and get rid of the soil. This year I have just bought some 6X 100% natural fertilizer having checked with the producer that it is definitely weedkiller free and has been 200° heat treated as well. So fingers crossed it should be O.K. Kaycurtis I would not use those bags if I were you!!!

Gardeners' World Web User 02/03/2009 at 16:10

allotments sorry didnt know how else to get hold of you... we have a landshare site in Winterbourne Abbas. Any one who is interested in a plot is more than welcome we have 6 spare contact me at clarke.miss@yahoo.co.uk

Gardeners' World Web User 03/03/2009 at 15:57

If you want to test for aminopyralid in your supply here's how http://www.allotment.org.uk/garden-diary/321/testing-for-aminopyralid-in-manure/

See more comments...