Franz Heymann wrote:
"Alan Gould" wrote in message
...

[snip]

Polytunnel covers need to be of ultraviolet inhibiting [UVI/EVA]
polythene of which three grades are offered. We chose Politherm
Plus
in 720g with anti fogging and high light transmission properties.

Why do polythene tunnel covers need to block UV radiation?
Surely the same plants, growing in the open thrive the full dose of
UV
radiation?

Isn't it to protect the material, not the plants?

Mike.