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

"Nick Maclaren" wrote in message
...
|
| In article ,
| Pam Moore writes:
| | 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.