Posts Tagged ‘EDTA’

As you know, our beautiful Manly Vale Community Garden is an organic garden. You can eat strawberries straight from the ground, firstly ascertaining that a small child has not wee’d on them; feast on mulberries straight from the tree. No need to wash.

We use homemade ‘fertilisers’ like worm juice and compost tea; coffee grounds, compost and animal manures. We interplant and ‘mix it up’ to confuse the bad bugs and lovingly plant special flowers like calendula and marigolds to attract beneficial insects.

We even sacrifice our pristine park-like grounds to scruffy seed saving. Are we doing well? Yes you betcha we are.

But…. then there is Marketing. Unless you have hours/days to spare on Mr Google or are a biochemist/scientist, at some point you have to take your organic supplier at face value. Or if you are a tiny bit paranoid like me, you do your research.

Just because something is marketed as organic does not necessarily mean it cannot be harmful. A point in example is Spinosad, an insecticide, derived from naturally occurring beneficial soil bacteria,  for the control of caterpillars, fruit fly etc. Spinosad has been implicated in the world-wide widespread decline in bee colonies ie it  has been found to be toxic to bees.

(For more information – http://www.bigpictureagriculture.com/2012/01/honeybee-decline-story-spinosads-and.html. There are many articles out there).

Which brings me to slugs and snails. I rather like snails as does my blue -tongues, so never need to use any control apart from a ring of ash or egg shells around my seedlings at home. However not everyone is the same and I have recently come across an organic snail & slug killer.

Multiguard Snail & Slug Killer, guaranteed  not to harm you, your pets or wildlife. Sounds good? Yes…but.

It’s all a bit confusing really.

The main ingredient is Iron EDTA complex. Ethylenediaminetetraacetic acid,(EDTA) a synthetic fertiliser. EDTA is a chelate. I remember from my soil lectures, chelates are not a bad thing, definitely something that will help your citrus if needed. “A  chelate is a soluble, organic compound that bonds with metals such as Fe, Mn, and Mg and increases their solubility and, thus, their plant uptake.  In essence, what iron chelates do is protect the iron from precipitation to an unavailable form.”  http://www.harrells.com/blog/irony-in-iron.

However, EDTA has not been given organic status. In 2007, as a snail bait, it was not added to the US National List on the recommendation of the National Organic Standard Board  because, “Is not consistent with environmental and compatibility with organic farming OFPA criteria primarily due to the behaviour of EDTA in the environment and the toxic chemicals used to manufacture.”


More information can be found at


Reading further I found that EDTA is used for soil amelioration especially where there is lead contaminated soil. The conclusions (edited) from the book Soil Remediation and Plants: Prospects and Challenges edited by Khalid Hakeem, Muhammad Sabir, Munir Ozturk, Ahmet Ruhi Mermut, are as follows:-

  • Soil- applied EDTA can adversely impact soil enzymatic and microbial activities
  • At high concentrations EDTA can negatively affect soil fungi and plants
  • EDTA complexes are not easily biodegradable and may persist in soil for several months
  • The complex is not ideal in terms of plant uptake and translocation
  • EDTA salt can destroy the physical and chemical properties of soil
  • At higher rates, soil –applied EDTA can result in eutrophication because of excessive release of nitrogen from EDTA
  • EDTA can affect soil nutrients status due to unspecified co-mobilisation of macro- and micronutrients

Not a good look. Not to mention the reported cases of toxicity to dogs.

I’ll stick to snail-nibbled veggies, thanks.







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