[Marijke Jones]

Dear fellow gardener,

Someone gave me copper to use on my potatoes which I grow in bags. I bought all my varieties from a certified seller and they are doing marvellous, not a mark on them and the first flowers are forming. As they do so well why would I use copper? Is it necessary?

[Yorkie]

I would be very cautious.

I realise you are in Ireland rather than the UK, but I guess that pesticide authorisation is likely to be similar.

The Defra garden database, when searched for the active ingredient 'copper', only authorises the use of copper oxychloride in grapes.

The RHS list of withdrawn chemicals lists copper oxychloride in all other situations, and copper sulphate (Cheshunt compound and Bordeaux mixture).

Just because a product is no longer licensed does not automatically mean that it is harmful to use; it can just mean that the licence owner did not want to go through the product renewal. But copper can be toxic, hence my reservations.

[AnneB]

Dear fellow gardener,

Someone gave me copper to use on my potatoes which I grow in bags. I bought all my varieties from a certified seller and they are doing marvellous, not a mark on them and the first flowers are forming. As they do so well why would I use copper? Is it necessary?

I suspect it might be intended to prevent blight, but I would not use it.   It has been banned for a reason.