Allotment Gardening Advice Help Chat

Growing => Growing in Greenhouses & Polytunnels => Topic started by: Ghost on May 20, 2011, 09:37

Title: maximum greenhouse temperature
Post by: Ghost on May 20, 2011, 09:37
I'm growing just toms and peppers in my greenhouse. What's the max temp I should let it get to before I start opening the door to cool it down?
Title: Re: maximum greenhouse temperature
Post by: Kristen on May 20, 2011, 19:22
I think a lot depends on how big your greenhouse is. Its much easier to control the temperature in a large greenhouse than a small one. Very small greenhouse are almost impossible to keep cool - short of painting them with the white "sunshade" or whatever it is called.

Ideally you want Convection cooling, rather than a Draught - which stresses the plants more, and makes them transpire more and then they need more water.

I like Louvre windows - e.g. opposite end from the door - which help the convection process.

But if the weather is warm best to throw the door open - the plants will prefer a cooler temperature (if it doesn't get as hot as you feared), including the draught from the open door,  rather than "over heating".

If you can fling some shading over the greenhouse on hot days, e.g. debris netting, that will help
Title: Re: maximum greenhouse temperature
Post by: yorky on May 20, 2011, 20:48
I would open the door at about 60f. Things grow very well at that temp. Only more tender and exotic plants need it warmer than that.