Greenhouse size

[tomuk56]

I have enough materials to make a 24ft greenhouse or x3 8ft greehouses joined together, from the heat retension and growing advantages which would you recomend.

thank you for any help

[dogsbody]

A big one can be divided up - you cannot make smaller ones bigger.......

[RedThorn]

I would put it up as a 24ft one sectioned into 2 or 3 sections. This way if you were to decide to heat your greenhouse next year, you could reduce the energy bill to do this by only heating 1 section.

[Peter]

The old-fashioned way was to have a door at one end only on a long structure.
That door opened into the coldest section.
Then there was a glazed division, with a door.
That door opened into a warmer section, using the coldest section as an airlock / lobby.
If you were well off this then repeated, so you had:
Outdoors [wall/door] cool section [wall/door] warm section [wall/door] hot section.

This did rather ignore the fact that each pane of glass looses heat equally on the outside. It concentrates on the sudden massive loss when the door gets opened and uses a cooler section to shield one end of the warmer.

Oh and the door was usually in the north end of a north-south house, which I reckon calls for a white-painted brick or breezeblock end for maximum insulation & reflection. If you can di it that is.

[tomuk56]

Thanks for the help,i never thought of the door in the north end ,or the heating problems of one 24ft house,so im going for a 8ft section in the south end to use as a seed house etc and 16ft beds for toms etc.

thanks again

[Paulottie]

Now, I'd completely bubble wrap the north end, put up autovents and use that for your nursery...easy to bake off seedlings. whereas fruit wants the sun.

[Peter]

Forgot to say there are other advantages in one bigger structure.
The ratio of volume to surface area is better.

1 cubic metre has 6 square metres of surface to loose heat through.
2 seperate cubic metres have 12 square metres of surface.
2 cubic metres (at 2x1x1 arrangement) has 10 square metres of surface.

So if you made 3 of 8x6 houses they will between them have 4 more ends to loose warmth through than the single 24x6 house.