Beware Compost Masquerading
As The Black Death...
A recent surge of reports of weed killer damage across many allotments and some gardens in the UK has been traced back to farmyard manures as the source of the contamination.
This contamination is caused by application of weed killers to pastures, which are then eaten by stock.
Plants affected: peas, beans and other legumes, carrots and parsnips, potatoes and tomatoes, and lettuce and similar crops.
Some ornamental plants, including delphinium, phlox and roses.
Typical symptoms include cupped leaves and fern-like growth on sensitive plants.
The shoot tips become pale, narrow and distorted, with prominent veining on the foliage.
The damage is caused by hormone-type weed killers, approved for use on grassland to kill broad-leaved weeds.
The active ingredient responsible for most of the damage is aminopyralid, though clopyralid, found in certain lawn weed killers as well as agricultural products, can also give similar results.
The weed killer is bound to the lignin in grass in the manure and released as the grass, hay or silage decays.
Plots already treated with contaminated manure: The Pesticide Safety Directorate (PSD) and the Food Standard Agency have investigated the risk to human health and concluded that produce from affected land is safe to eat.
You can attempt to do so by contacting the supplier of your manure in the first instance to discover which weed killers were used and who the manufacturers are.
The PSD website holds information on both amateur and professional chemicals.
Dow AgroScience, who manufacture aminopyralid-based products such as Forefront, is offering advice to gardeners and allotment holders on their website.
To speed up the rate of breakdown of residues on contaminated land, rotovate or dig over the soil several times, preferably between summer and autumn when the soil is at its warmest.
If they cannot be incorporated into the soil, bag them up and put out with household refuse (NOT green waste collection).
Seek advice from your council if they won't accept green waste in domestic refuse.
The best advice is to return the unused manure to the supplier for them to spread on grassland.
If a reliable source of manure is not available, try using an alternative source of organic matter such as garden compost, leaf mould, composted bark or composted green waste from your local council.
I sincerely hope that none of your soil has been affected - make sure too, if you are purchasing bagged composted manure from your garden centre that they can assure you of its quality.
If you haven`t already and you have enough room then this is another reason for making your own compost at home.
PS... pass this on to a friend or family member if there is a chance that they could become a victim.