So im doing an outdoor grow and with the bad weather growth is really slow, if I was to put one of these over it do you think it will help? Temperatures here are oly between 12-20 degrees celcius; http://www.ebay.co.uk/itm/WALK-IN-OUTDOOR-GARDEN-GREENHOUSE-SHELVES-PLASTIC-COVER-STEEL-FRAME-MINI-LARGE-/360584642885?pt=LH_DefaultDomain_3&var=&hash=item53f4850145
It wont help your lighting at all, but it would keep your temps higher and somewhat more regulated. I have never used a greenhouse, just stating what i know ^_^