Jonathan Campbell wrote:
[...]

(Incidentally.) I'm told that in this neck of the woods, a farmer
practice is, if the potato crop has emerged and there has been frost
during the night, they spray them with water before the sun comes up ---
using the sprayer normally used for anti-blight spray and for killing
seed potatoes.

The rationale for the damage prevention was explained to me but I've
forgotten.

I'll ask and report back; maybe useful for gardeners?


I phoned my informant just now and here is /his/ explanation: the
spraying of water is to wash the (hoar sp.?) frost off the plants before
the sun thaws it; (hoar frost = frozen moisture that has condensed out
of the air). I'd say some thawing takes place while the hoar frost is
still in contact with the plant, but maybe the thawing is much less
rapid and this has some moderating effect on what happens to the plant
cells.

No, I'm not convinced either. I studied (attended) thermodynamics
courses at college but none of it ever clicked with me.

Also, the stories of spraying with water /before/ threatened frost do
not exactly tie in with what I say above.

I'll enquire further.

Jon C.