Greenhouse Temperatures 100 deg!

In the current heatwave I'm recording very high max temps. Yeterday it got to 38 deg C (100 deg F). I think I've had this sort of temp in previous years and it hasn't affected growth. Anyone know if this too high for tomatoes/cucumbers?

 

John,
do you have any greenhouse shading? It may help somewhat but I think that they will survive OK. The usual problem with toms and cues in the same greenhouse is that they like different standards of humidity.

Kristen,
I have the same situation as you and think it is a combination of both. I never bother with shading as the glass has accumulated over 30 years of 'natural' shading :hehe:

 

Kristen, I'd be interested to hear what you max temp is.


"do you have any greenhouse shading? It may help somewhat but I think that they will survive OK"
Shiney, for the first year I haven't bothered with any shading - in the past I've put on that whitewash stuff but as last year was so poor I decided to see if lots of light might give a better result. I positioned my new runner bean frame right next to my main tomato greenhouse (sounds posh doesn't it!) hoping that would provide natural shading:



The bean frame is due south of the greenhouse (photo taken 3 weeks ago - beans are now up to the top), but what I didn't consider is that the sun's angle is so high this time of year, so its just shining right over the top of the beans, so that idea didn't help.


"The usual problem with toms and cues in the same greenhouse is that they like different standards of humidity"
True, I have a seperate cucumber greenhouse which is much more in the shade (under some big trees) so I can get the humidity higher in there.

It doesn't take long to put that whitewash stuff on, but I'm dithering as both my cucumber and tomatoes don't seem to be stressed by these really hot conditions, both are growing very well and fruit are ripening at last.

You can see from the photo that my glass isn't too clean either!

 

John,
If you are concerned about the heat, and leaf burn, then you can put shading just on the roof. This will protect the toms from the strongest sun but allow loads of light through the sides.

Your glass is spotless and totally transparent compared to mine :hehe: :rotfl:. I would be ashamed to show it on here :o :D

 

I'm afraid to scrub it as the greenhouse might fall down :D. That's my excuse and I'm sticking to it :hehe:

 

Thats ideal. I think we dumped one from my daughter's flat a couple of weeks ago :(

 

Well mine went to 39C today, and a couple of tomato plants have wilted, but thats because they are in pots and dried out a bit, I gave them a drink and they have perked up again. I don't have any envromesh or debris netting, I'm getting by with some cheaper netting I've had for years on the brassicas. Tomorrow I'm going to throw a couple of sheets of fleece over the top (weighted down at the edges with some timber to stop it blowing off). I reckon that will probably be enough to keep it reasonable until this heat wave ends.

 

We don't have a thermometer in the greenhouse but we are quite lucky that there are four top vents and six bottom vents in there. We also have a thermostatically controlled electric fan built in to the end of the greenhouse. I always have this set to blow air into the greenhouse. I was told by the greenhouse manufacturers to do it this way, for technical reasons, but can't remember what they are . That was in 1976 :hehe:

 

I put the fleece over the top this morning so I'm hoping that will keep it reasonable, they are predicting an even hotter day today.

You can't have too much ventilation shiney, I have one auto-vent in each greenhouse plus a manual side vent. Then I throw the doors wide open of course. I got my main greenhouse in 1977, its followed us on all our 3 house moves since - its like an old friend!

I went a bit mad with the watering in the main greenhouse last night, the humidity is up to 95% which is way too much for tomatoes :o, if this was later in the season I'd be risking getting fungal diseases in there.