greenhouse dimensions/decisions

[nutgirl]

I am now the proud owner of an older 8 X 20 greenhouse in pieces. (Whew! That was a job!)

I have several decisions to make and I would appreciate any input from greenhouse owners.

I live in an area that gets hot, dry summers - cool, wet winters. For economic reasons, the GH will currently not be heated. (the plants have to come indoors if it gets too cold for them)
The temp in the summer will be 90-95 max using shadecloth, fans, misters and possibly a swamp cooler (if Craigslist will cooperate).

I currently have a 6 X 8 GH. My original plan was to build one 8 x 12 or 8 X 16. 8 X 20 is bigger than I need and I can go smaller but I have room for it and can always use the space for storage unless it’s going to cause problems.
Is 8 X 20 practical, is it a size that would make it hard for me to control temperature/air movement?


The GH frame is galvanized steel. The roof frame is made of 2’ high trusses and I want there to be at least 6’6’’- 7’ from the GH floor to the bottom of the truss crosspiece. This will make the side walls 6’6” - 7’ and the peak 8’6” - 9’.
Would a higher peak be better? Overkill?

I am thinking of building a cement block knee wall, 2 blocks high. I have read that the cement stores heat and is helpful in cooler seasons. (my overall sidewall height would still be 6’6” - 7’)
Does anyone have an opinion one way or other?

The GH was covered with corrugated fiberglass panels. Polycarbonate seems to be the current covering of choice. I know it'll be hot in there no matter what. Is there any difference from the plant’s point of view?

Thanks for any info.

Maureen

[dounoharm]

hi maureen! how exciting!!! as far as controling the temp...do you have ceiling vents?? you will most definately need them....and loads of fans to move air thru a 20 rather narrow gh....8' doenst seem like its wide enuf, but you have to make do with what you have....i like the idea of a kneewall, and i would go for the extra height too, more space will make it easier to cool and heat if you ever do that.... the plants wont care if the gh is corrogated or polycarbonate....but your purse will, and if you have no need to heat in the winter, then i would go with the cheaper covering.....bear in mind tho, you might decide to heat one day....and the thicker polycarbonate would insulate better....my gh runs about 95-98 on the hot days with the exhaust fan running and the ceiling vents open....hope this all helps, and enjoy it!!

[nutgirl]

Originally Posted by dounoharm

hi maureen! how exciting!!! as far as controling the temp...do you have ceiling vents?? you will most definately need them....and loads of fans to move air thru a 20 rather narrow gh....8' doenst seem like its wide enuf, but you have to make do with what you have....i like the idea of a kneewall, and i would go for the extra height too, more space will make it easier to cool and heat if you ever do that.... the plants wont care if the gh is corrogated or polycarbonate....but your purse will, and if you have no need to heat in the winter, then i would go with the cheaper covering.....bear in mind tho, you might decide to heat one day....and the thicker polycarbonate would insulate better....my gh runs about 95-98 on the hot days with the exhaust fan running and the ceiling vents open....hope this all helps, and enjoy it!!

Thanks for your input!
The original GH did not have roof vents, just a exhaust fan in one end and a shutter opening in the other. I plan on putting in vents.
I agree, the size and shape will need quite a bit of ventilation.
For the time being I'm thinking of reattaching the original corrugated panels and assessing things after this year. That way I can experiment with the whole thing before I decide on the covering.

This should be fun!

Maureen

[dounoharm]

thats an excellent idea! be sure to post pictures of your progress and how things work out, its an interesting size and shape!