Tomatoes & Bordeaux mixture

 I have just picked my first tomatoes for 5 years, having lost all to
blight for the last 4 years.
This year for the first time I have used Bordeaux Mixture which is
suggested as the nearest organic control.
Now I am concerned about the white copper sulphate deposits on the
fruit.  
Is copper sulphate toxic?  

Does anyone know how thoroughly I need to wash them?
Has anyone else used BM?  Advice is to spray weekly.

Pam in Bristol

 
|> I have just picked my first tomatoes for 5 years, having lost all to
|> blight for the last 4 years.
|> This year for the first time I have used Bordeaux Mixture which is
|> suggested as the nearest organic control.
|> Now I am concerned about the white copper sulphate deposits on the
|> fruit.  
|> Is copper sulphate toxic?  

Yes, but not catastrophically so.  You need micrograms of copper
a day, the odd few milligrams on occasional will almost certainly
do no harm, and the lowest lethal dose recorded is of the order
of a gram.

|> Does anyone know how thoroughly I need to wash them?

Moderately.  No need to panic, but do wash them.

|> Has anyone else used BM?  Advice is to spray weekly.

Yes, on potatoes, where the problem doesn't arise.  Weekly seems
a bit excessive, but the issue for tomatoes is whether there has
been heavy rain since you last sprayed.


Regards,
Nick Maclaren.

 What makes you think that the white deposits on the tomatoes are in fact copper
sulphate?
Last I heard was that copper sulphate crystals were blue!
Regards,
Chris in Somerset

|
| |> I have just picked my first tomatoes for 5 years, having lost all to
| |> blight for the last 4 years.
| |> This year for the first time I have used Bordeaux Mixture which is
| |> suggested as the nearest organic control.
| |> Now I am concerned about the white copper sulphate deposits on the
| |> fruit.
| |> Is copper sulphate toxic?
|
| Yes, but not catastrophically so.  You need micrograms of copper
| a day, the odd few milligrams on occasional will almost certainly
| do no harm, and the lowest lethal dose recorded is of the order
| of a gram.
|
| |> Does anyone know how thoroughly I need to wash them?
|
| Moderately.  No need to panic, but do wash them.
|
| |> Has anyone else used BM?  Advice is to spray weekly.
|
| Yes, on potatoes, where the problem doesn't arise.  Weekly seems
| a bit excessive, but the issue for tomatoes is whether there has
| been heavy rain since you last sprayed.
|
|
| Regards,
| Nick Maclaren.

 
|> What makes you think that the white deposits on the tomatoes are in fact
copper
|> sulphate?
|> Last I heard was that copper sulphate crystals were blue!

Bordeaux mixture is not just copper sulphate, and looks whitish
when the spray dries.


Regards,
Nick Maclaren.

 
"Nick  wrote in message ...

fact copper

And don't forget the lime, Bm is a copper sulphate and lime mixture.

--
Bob

www.pooleygreengrowers.org.uk/ about an Allotment site in
Runnymede fighting for it's existence.