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Plot holder worried by weedkiller

Posted: Wed Aug 17, 2016 12:22 am
by Barry
I wonder if you can help.

A brand new plot holder who has never grown vegetables before says that she wants to grow organic vegetables. She only eats organic vegetables.

However, on the plot she has just taken, we previously used Roundup given that the previous owner had used a rotavator to try and clear twitch/couch - and turned it into a nightmare plot.

She has now done some research and says that weedkiller stays in the soil for seven years, so she doesn't want it. She won't be able to grow organic vegetables, she says.

As far as I am aware, Roundup disappears on contact with soil.

Is she right to turn it down?

I'm personally no fan of weedkiller, but think it is OK for clearing plots, not for controlling weeds when you are growing vegetables.

Re: Plot holder worried by weedkiller

Posted: Wed Aug 17, 2016 10:16 am
by FredFromOssett
My understanding of glyphosate based weedkillers is that they do not leave any residue in the soil, and as such I should have thought that any vegetables grown subsequently in that ground could be regarded as organic. Having said that, presumably the weeds which have been killed and then decayed in the soil will have had glyphosate in their decayed matter; what happens to that residue?. Does that then count as a non-organic contamination? Personally, I should have regarded that as OK, but I am not really a chemist, nor am I totally obsessional about eating only organic produce. Whilst I prefer to garden largely organically, where possible, I am willing to succumb to using possibly non-organic measures where necessary.

Re: Plot holder worried by weedkiller

Posted: Wed Aug 17, 2016 2:44 pm
by alan refail
Even the Soil Association has only a two year conversion period before they grant certification. And that covers any chemicals. The seven years is nonsense.

You could show her this, which is by no means pro-Glyphosate.

http://www.rsc.org/chemistryworld/2016/ ... ent-health

"Field studies cited in the report show the half-life of glyphosate in soil ranges between a few days to several months, or even a year, depending on soil composition."

Failing that, you could always let the plot to someone less hysterical.

Re: Plot holder worried by weedkiller

Posted: Wed Aug 17, 2016 2:52 pm
by Tony Hague
Glyphosate decomposes in contact with soil, and the bigger problems are where it is used on pavements, roads etc where it washes directly into waterways. I think I've read that it, and the things it decomposes to, can remain around for longer than the manufacturers would like you to believe.

But on the other hand, if she eats organic veg she may easily have eaten crops off land that has had glyphosate on it a lot more recently than 7 years ago. Organic conversion periods are only 2 years, and a goodly dose of glyphosate is almost invariably the last non-organic act before starting conversion with a nice clean field.

If you eat non-organic cereals, they may well have been sprayed with glyphosate pre-harvest; officially to clean up weeds in the crop for easier harvesting, unofficially to speed up senescence. Almost certainly we are eating glyphosate (and its metabolites) in that.

Re: Plot holder worried by weedkiller

Posted: Wed Aug 17, 2016 3:10 pm
by Pa Snip
alan refail wrote:Failing that, you could always let the plot to someone less hysterical.


I like that approach Alan.
I'm wondering how anyone might establish that ALL the seeds they sow came from organic source.
What about any bushes or trees planted, can they be guaranteed organic.

The problem with weeds is that they like to align themselves to chickens, Free Range, and that's another can of worms

Re: Plot holder worried by weedkiller

Posted: Wed Aug 17, 2016 3:51 pm
by Barry
No more than three litres of Roundup was used on an area of about 90 square metres.

The soil is heavy clay.

I'm guessing any trace would therefore be gone in - months?

Re: Plot holder worried by weedkiller

Posted: Wed Aug 17, 2016 7:59 pm
by robo
She sounds like a bundle of joy to me , I would let the plot to someone else

Re: Plot holder worried by weedkiller

Posted: Wed Aug 17, 2016 11:14 pm
by snooky
Seems to me that she has believed the propaganda put out by the anti- Monsanto brigade on other gardening forums;or using it as an excuse because when seeing the site she realised how much hard work it would be to sort out.

Re: Plot holder worried by weedkiller

Posted: Thu Aug 18, 2016 12:01 am
by Barry
I am being quoted the following:

https://www.soilassociation.org/media/7 ... y1docx.pdf

https://www.gardenorganic.org.uk/glyphosate-debate

Any thoughts on how I should respond?

My new plot holder is paranoid about not feeding her children "cancer causing agents".

Would I be right in thinking that the nearby A road is probably a bigger threat than the Roundup in this respect?

Re: Plot holder worried by weedkiller

Posted: Thu Aug 18, 2016 6:25 am
by alan refail
Good morning Barry

The Soil Association essentially say that the jury is out on the effects of glyphosate.

The Garden Organic will scare her more as it's phrased in semi-religious terms - "contrary to our organic beliefs". It was when Garden Organic (formerly the Henry Doubleday Research Association) became a belief system with a semi-religious zeal that I cancelled my membership after decades. I remain organic in the little gardening I do now.

If you are feeling brave you could show her this, though it might put her off life altogether.

https://www.theguardian.com/society/201 ... ancer-list

The risk from vegetables grown on her plot is going to be infinitesimal as weedkiller use has stopped. Unlike atmospheric pollution which is constant. And she stands more risk from talcum powder and sausages!

If she uses the plot she will know what she is growing and how. If she doesn't she can buy vegetables, which she knows nothing of the production of, even if labelled organic. Remind her that according to Soil Association rules, land only has to be free of chemical use for two years before certification.

Alternatively give the plot to someone else.

Re: Plot holder worried by weedkiller

Posted: Sun Jun 04, 2017 3:02 pm
by robo
I know this is an old post but ,a few weeks ago I made my own weed killer mainly as an experiment it worked very well not only did it kill every weed it was sprayed on but over a month down the line and nothing has grown again it also works quickly in about three days ,2 litres of coke , 1 litre of vinegar , 1/3 of a bottle of cheap washing up liquid mix all together and put in a sprayer , I have used coke for cleaning the engine and bilges on our boat for a few years God knows what it does with your intestines

Re: Plot holder worried by weedkiller

Posted: Sun Jun 04, 2017 7:06 pm
by Westi
Evening Robo!
Not heard of putting coke in the vinegar mix. I use the vinegar mix which does actually work but not that quickly. Thanks for the tip.