Story by Pete Wrapson

June in Jamie’s vegetable garden is marked by feelings of excitement and anticipation. The first wave of the summer’s harvest arrives: baby broad beans swell in their velvety pods, plump strawberries ripen in the sun (if you remember to net them against birds and go slug-hunting at night, that is) and new potatoes are ready for digging, treasure buried in warm soil. There’s an optimism that comes with the still-lengthening days, that this

 />Pete Wrapson, Jamie's gardener</div>
<p> could be one of the great summers. So, with that hope in mind and in addition to the usual legion of tomato plants, I usually plant a few sweet peppers and aubergines out in a sunny, sheltered spot just in case the summer is long and warm enough for them to ripen properly. </p>
<p>I wish I could say the same, however, about my own two allotments (yes, I grow veg in my spare time too, which probably makes me a glutton for punishment”¦) Much to my annoyance I have unwittingly contaminated much of my growing land with horse manure that contains herbicide residue. </p>
<p>The chemical in question is called aminopyralid and it appears in a number of herbicides marketed since 2005 by Dow AgroScience. It is a selective hormone-based herbicide designed for use on grassland, the idea being that the grass itself is not damaged but broad-leaved weeds, such as docks or nettles, are. Aminopyralid binds strongly to plant material and disrupts the functioning of hormones that control growth. The plant becomes badly distorted, is weakened and dies. Even the residue can be damaging: in affected vegetables, yields are poor or non-existent. Plants particularly susceptible include potatoes, tomatoes, peas and beans, but there are many others, including some ornamentals. I first noticed that something was wrong in early May when the leaves of my potatoes emerged curled and stunted. </p>
<p>It is often hard to trace the source of contamination, as the herbicide can get into manure in a number of ways. It may simply have been sprayed on the animals’ pasture. They eat the grass and excrete the chemical in their manure. It could also have been imported in forage such as hay or silage, both of which get mixed up in the muck-heap. Aminopyralid is broken down by bacteria in the soil, not in isolation, which means it can persist in heaps for several years. Although Dow suspended sales of these products last summer, when instances of contamination first appeared, the problem will not be over for a while.</p>
<p>The Royal Horticultural Society suggests that affected soil will be safe to grow in next year. However, to help the process I should remove as much manure as I can from the surface and either return it to the supplier or put it in council refuse. The green bin or my own compost heap must not be used: any affected plant material in compost that is later returned to the soil will still contain the chemical. Next, I should regularly dig over or rotovate my beds through the summer so that the remaining manure is chopped into smaller pieces, speeding up the process by which the chemical is broken down. </p>
<p>If you use manure yourself, talk to your supplier about this issue. There is more information available on the internet than I have been able to include here. The RHS website is a good starting point.</p>
<p>Fortunately all’s fine here at Jamie’s – we use certified organic mushroom compost as a soil improver – and I shall be back later in the month to talk about artichokes and cardoons.</p>
<p>About the Author: Pete Wrapson is a very experienced gardener who lovingly takes care of Jamie’s garden in Essex. Do you have any similar experiences or hints and tips about composting and fertilizer’s then <a href=log onto the forums and let us know.

Grow your own: Jme sells some fantastic organic garden vouchers which you can use to get your own garden growing. The staff at Jamie’s office bought the small vegetable garden voucher which had over 100 plants that are now growing in our backyards and even in pots on the windowsill in our office.