[Tom Hill]

Last year will be remembered for its wetness and potatoe blight.
I saw this suggestion on a Suttons catelogue and thought it might be worth a try.
A weekly spray with a mixture of one part semi skimmed milk to seven parts water was very effective in prevention of blight.

[wil4025]

Did you try this last year?

I managed to save a lot of pots from blight, but had reduced yields.

[Tom Hill]

No, but I will this year.

[solway cropper]

These 'remedies' don't prevent blight. If you're lucky they may slow it down a bit but that's all they can do. Once you've got it that's it.

The idea behind using milk is that the calcium in it stops the blight developing as it prefers a slightly acidic environment. Unfortunately milk is slightly acidic (lactic acid) so it's not really much use.

If you don't want to use chemicals then grow blight resistant varieties or stick to earlies. The changing climate that we seem to be experiencing is going to mean a lot of old ways of doing things are no longer viable.

[DD.]

These 'remedies' don't prevent blight.

Of course they won't. By definition of the word, a remedy can't prevent anything. It comes after the event.

The OP mentioned it as a prevention, not a cure.

I won't hold my breath on it's effectiveness though.