Page 34 - Simply Vegetables Spring 2022

Letters
Dear Editor,
On Christmas Eve I received my copy
of Simply Vegetables magazine for the winter period 2021 / 22 and on page 13 there was an article by Elizabeth Maunder on “Should we reconsider how we exhibit our vegetables?”. It was very interesting to have a person’s opinion which was mainly growing vegetables with the emphasis on organic growing and exhibiting worked for her. The article was very interesting and well written.
However, I wish to point out that in paragraph 3 she was concerned rightly
so about using chemicals that might contain Carcinogenic properties. In the following paragraph she wrote about using blood, fish and bone fertiliser and growing comfrey which is cut and places in a bin that is filled with water which is left until the following season then used as a plant food – this is fine and common organic practice, but she goes on to say she removes blackfly by rubbing them off or by making a tea with rhubarb leaves and using the
tea as a spray. Now this has carcinogenic properties as it contains a carcinogenic substance.
I think that she should be informed of the danger of using this brew and if I had her address, I would write to warn her of her peril, will do so via Simply Vegetables instead.
Yours in Friendship, R.G. Tudor FNVS.
Roy raises a good point here and I have to admit when I first read Elizabeth’s article, I nearly removed the part on using rhubarb leaves. The NVS has a policy (if that’s the right word) not to recommend or suggest non approved pesticides. As it was in an article written by a member I (possible
unwisely) left the sentence in. All materials / substances used as a pesticide in the U.K have to be approved and have a number, usually called the MAFF number. There
are a few substances, usually food grade products that are used in the production of various food products and therefore should be safe enough to apply to plants that will be eaten like vegetables. Examples include bicarbonate of soda, vinegar, washing up liquid etc.
Going back to Roy’s point about rhubarb leaves being carcinogenic, I looked into this, and the evidence was not conclusive even when looking at “authorative” websites, some mentioned possible links to cancer but just as many said this was not the case. The first one may be why some people think rhubarb leaves are dangerous bearing in mind the history.
History
During World War I rhubarb leaves were recommended as a substitute for other veggies that the war made unavailable. Apparently there were cases of acute poisoning and even some deaths. Some animals, including goats and swine, have also been poisoned by ingesting the leaves.
Source
Toxic effects originate from the leaves of rhubarb plants rather than the edible stalk part. The plant contains oxalic acid, known to be toxic, and Anthraquinone glycosides which are suspected to be toxic. Oxalic acid can also be found in spinach, brussels sprouts, cauliflower, and broccoli but in lower concentrations.
Rhubarb leaf insecticide
The main factor in rhubarb leaves is the oxalic acid which is at a higher level in the
leaves than the rest of the plant and it is this that acts as the insect killer. Below I have set out a couple of paragraphs from a website which set out the situation well.
Extracting the oxalic acid from rhubarb leaves is a traditional remedy. It was made by boiling rhubarb leaves and adding soap flakes (or a soft soap of some kind as a wetting agent). Once correctly diluted, the mix was sprayed on plants, mostly to control aphids.
This all sounds rather innocent and
thrifty: however, rhubarb leaves are fairly toxic, particularly if drunk (not that you’d do such a thing, but a small child may and you wouldn’t want to spray it on anything you’d eat raw). As it’s not a registered pesticide,
it is illegal to make your own rhubarb- based spray. And rhubarb is not a selective treatment. It will take down any insect, so there’s a chance you will kill the good guys, too. When it comes to getting rid of aphids, ladybirds, lacewing larvae, wasps, garden birds and healthy soil come with a fraction of the risk and all the thrift of rhubarb leaves.
Finally from the RHS website the current legal position:
All pesticides must be approved. While
it is not illegal to use unapproved materials such as washing up liquid, coffee, vinegar or baking powder, it is good practice to only use products that are officially approved
for use in the garden. It is illegal to sell unapproved products for use as pesticides.
Dear Kelvin,
Re: Recycling
A few years ago, I had a new conservatory roof fitted and asked for the old roof to be left behind. I cut the old polycarbonate panels in half and use them as cold frames (and protection from rabbits?)
by propping them up with metal posts from a discarded (skip!) mini greenhouse. Easy to erect and move whenever needed and I can cover them with netting to prevent the pigeons accessing.
Re: Apricots
Thank you for the article on Apricots in the January edition, I have recently removed an old fig tree which has left me with some space on a South facing garage wall. Now I’m awaiting delivery of a wonderful apricot tree and my brother is awaiting delivery of apricot jam!
Kind Regards, Anne Hemsley
34 Simply Vegetables