In message , the swede
writes
Thanks for all the advise, have managed to solve the problem, using a
piece of wood and the greenhouse is still well ventilated. Now, I have
bubble wrapped my greenhouse but have not done the roof, should I have
done this, I had it done last year but took it off to let light in in
the summer

Most definitely. You'll lose more heat through the roof than you would
through the sides. See if you can find some trouble free way of
suspending it. I have canes running the length of the roof and just
drape the bubble wrap over these, so it takes about 30 mins to put up
for winter and about 15 mins to remove.


--
Kay Easton