"Chuckie" wrote in message
oups.com...
I have bubble wrap insulation covering the north and south walls and on
the east and south walls to bench height.
I think I will try the barrel and water idea.
The dimensions of the greenhouse are 12W x 20L x 8H.
Chuckie in the frozen north zone 5

Go to any car wash in your area. We throw away at least one 55 gal drum
every week. They'll be happy to give it to you, instead of having to send it
to the recycler or dump. If you're lucky they might even have a few drum
plugs laying around the equipment room.

Because many car washes still use ammonium bifloride (ABF) or hydrofluoric
acid (HF) be cautious of drums marked as wheel cleaner. If you use them,
wear gloves and flush the inside with water several times.

Water heats and cools very slowly, so this will work both ways, in the day
time the greenhouse won't heat up as quickly, and at night it won't cool as
quickly. Which may be to your advantage in the summer.