George.com wrote:

does it have to be a concrete floor?

You can have a dirt floor if you want. Depends on the uses you will put
the greenhouse to. The one I made was next to the back of the house and
also served as a makeshift conservatory so the concrete floor was handy.
I spent many a happy hour in there in the evenings with a good book and
a pint or two of home-brew surrounded by hundreds of my favourite plants
watching the sun go down. :-)

--
David in Normandy.
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