"Pam Moore" wrote in message
...
On Wed, 13 Aug 2003 11:57:02 +0100, "CK"
wrote:

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!

It says "Bordeaux mixture" on the pack.
It says it contains copper sulphate BUT the powder inside and the
deposit left on the plants is white. I also thought it would be blue.
Perhaps someone can explain!

When copper sulphate is very finely powdered, it loses nuch of its blue
colour. And, there is white calcium hydroxide in the mix as well.

[Franz Heymann]