Greenhouse temperatures...

stevek_bath · May 2020

We have a polytunnel greenhouse on our allotment and thought it was a good place to grow our toms and peppers this year.

At present we have all our tomato, aubergine and sweet bell pepper plants in there in small pots. They seem to be growing well but we've noted that the daytime temperatures in the greenhouse (even with air panels/door open) is touching close to 50 degrees at times over the last week or two.

At nights this has been dipping down to just under 10 degrees (celsius).

I've read this may be too hot for tomatoes. Am I better moving the pots outside during the days (around 25degrees typically this week)?

Fairygirl · May 2020

The temps have been exceptional recently, and they would probably be ok outside for a while, but severe sun catching tomatoes during the day can cause a bit of leaf scorching. Can you put them somewhere with a little shade during the day, at least when the sun is at it's peak?
The temps dropping to 10 or below are also a bit low for them, although if they're already quite mature, they might cope. Somewhere from 10 to 12 and above are fine. The odd night is ok though.
It's the fluctuation between the two that often causes the problems.
I can't advise on the other plants as I don't grow them.

Hostafan1 · May 2020

My Polytunnel regularly exceeds 50C and I've never had trouble with tomatoes. Get the doors open early before it gets super hot in there,and close them up before the temperture dips too low. That way you're not subjecting plants to rapid temperature changes.

Fairygirl · May 2020

That's the problem with the plastic isn't it @Hostafan1?
That's good if it doesn't affect them adversely though.

It's like those wee diddy plastic greenhouses - almost impossible to get them steady, and I always made sure to close up before temps got too low. Even the little greenhouse I have now is similar, but it's nothing like as bad as those plastic ones.

Greenhouse temperatures...

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