Greenhouse temp

[chickenfeet]

Hi,
I have an ordinary 8x6 greenhouse in which I'm growing tomatoes, melons and chili's. I'm a bit worried about the fact that the temperature inside gets to around 38C during the day. Nothing seems to mind as everything seems to growing ok but it is very hot in there.
Some of tomatoes have just started producing a couple of huge flowers near the top. I read on the other forum this could be from too much cold but could the heat also cause this? Am I likely to get a small crop now?
What temperatures should I be aiming for in there and whats the best way off keeping it cool? I currently have the door and roof window fully open all day. If shading is the answer, what is the best side to shade(north, south etc)? And is fleece sufficient?
Will the plants suffer through less exposure to direct sun?

Sorry for all the frantic questions, I'm new to greenhouses this year so any advice is appreciated.

Thanks

Dale

[chickenfeet]

[sandersj89]

Anything over 30 can stress the plants and it is best to try and avoid it if you can. Doors and roof vents open are a must and shading on the outside of the glass will help.

Fleece, old net curtains, green mesh, old bamboo curtains, Venetian blinds, etc, etc will all work.

Best on the south and south west facing areas of the roof and sides of the house to reflect the heat in the hottest part of the day.

Jerry

[tim]

Read back on shading - even with shade & vents, I still can't stop it getting to 85F in this weather. Not good for growing. But not fatal!!

And that is measured in the coolest corner of the 'house at ground level.

[MikeB]

I've rigged up a fan in my greenhouse (8x10) which comes on at midday and off at 4 o'clock, this drops the temperature from the mid 30s C to the mid 20s C. Door and two skyllights + 1 louvre window are open. As stated without the fan the temperature is in the 30s, so I think it is down to the lack of air circulation that keeps the temperature up.  I have a solar fan fitted to my workshop that works reasonably well, next year I'll fit one to the greenhouse. Available at caravan outlets.

[chickenfeet]

Thanks for the info.

Mike- What sort of fan do you use in your greenhouse to create sufficient airflow?
Do you have mains power or running from a car battery etc?

Thanks

Dale

[MikeB]

Hi Dale,

Full size office fan running off mains electric.

[Growbe]

It sounds like you have the right plants in there.

The Melons and Peppers should love the heat. The Toms though will need to be monitored.

I would suggest dampening down the greenhouse though because in really dry conditions spider mite may move in and become a problem.

If you are really worried moving some plants outside to give them "rest" would not be a problem in the current climate as long as they go back in over night.