I would have an attack in anticipation of something like that!
Let me throw out something to consider. You might consider turning it into a lighted "grow building", rather than greenhouse. Heating is pretty costly, solid block walls will rally limit the light entry, as you will only get it for a few hours around midday, and electrical lighting gives you a lot more control of the environment.
Ray Barkalow
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Heating will not be much of an issue as I live in zone 10b. It will require only a minimal amount of supplemental heating and only for a few days a year. I think airflow and maybe some occasional supplemental lighting. An auto watering/misting system would be nice!
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