Bluedog0628

Greenhouse temperature - how hot is too hot?

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Hello everyone, 

I have a weather related question.

I have my plants in on of those collapsible 2-tier plastic greenhouses. It gets full sun from around 8am till 4pm. Today the outside temperature was 23 C, temp inside the greenhouse (with the front panel fully opened) was 42 C (humidity between 40-60% depending on the time of the day). Is it too hot? The plants I have in there are: Drosera binata and capensis, VFT, Darlingtonia, Sarracenia purpurea ssp. purpurea and Utricularia bisquamata. Plants are in 4" pots (except the purp in 5" pot) and all pots are standing in water trays.

Thanks!

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I would disagree. Darlingtonia in particular is known for needing a cool root run, and S. purpurea and D.binata are notably hardy - not likely to be tolerant of extreme high temperatures.  

Why have them in a greenhouse at all at this time of year -  I'd just put them outside as soon as night temperatures are above 5oC. The sundews will appreciate protection from rain, but that's it, or perhaps you can raise the back of the greenhouse as well to get a through draught?

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Darlingtonia needing cold roots is massively overhyped in my experience. Mine just live with my sarracenia in the greenhouse and do fine. Same with purp ssp. purp. Either will be about 5 weeks behind their greenhouse brethren if they live outside.

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Hi and thanks for all replies.

Last year the Darlingtonia was grown in same conditions as the purp and did just fine (it sent out a few stolons so I guess it was happy). I was a bit worried at first (I've read all the stories of plants dying on the internet and the root cooling problems etc. so wasn't sure how it would work) but things worked out ok. I think the root temperature might be a problem in really hot countries but UK is not that warm (not for long anyway). I have pots arranged in two rows and the Darlingtonia is in the middle of the back row (the surrounding pots provide some sun protection and that seems to be enough to stop the roots overheating).

The reason for keeping the plants in a greenhouse is this: I am surrounded by football mad kids (2 of 3 my neighbours have goal posts in their gardens and regularly have their kids' friends over). I have lost count of how many footballs came flying over the fence in the past year (just this weekend alone I had to retrieve a football - a real, heavy leather football - from my garden on 5 occasions). I dread to think what this football would do if it managed to land on top of my plants (remember, they're in 4"-5" plastic pots, so nothing particularly sturdy). The greenhouse isn't really there to keep the plants warm, it's there to keep them from getting squashed/broken (the open panel is facing my other neighbours, an elderly couple, so no risk of a stray football coming from that direction). The greenhouse itself has been hit by a ball in the past a few times but luckily it's anchored well enough to stop it falling over (there's about 100l of compost on the bottom shelf and a string going round the top and tied up to a waste pipe). I was planning on getting a bog planter last year (didn't get round to actually making one) but as it happened, the kids really stepped up their game since then and I don't think it will be possible now (not unless I can find a way to keep the balls out).

Hopefully the weather will go back to more reasonable temperatures soon. For now plants are kept standing in water and fingers crossed, everything will be fine.

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The only common cp ive found struggles in high temperatures is D. aliceae.  

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Thanks manders, I don't have D. aliceae (and not thinking of getting one either)... What about D. regia (would like to have that one)?

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Hi, the 42 C was in sun. The greenhouse is south facing. I did try to get some shading (well, it was a piece of cardboard wedged between the cover and the frame, it did not go quite to plan as it warped by next morning due to high humidity and it blocked out most of the light) and the temp dropped to 35 C. Will need to get something more suitable before the summer weather returns (would horticultural fleece work?).

Today the temperature was 30 C in sun (without any shading).

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IMG_1839.JPG.30243cd744f03c41681a11d91a9eee4e.JPGTemp should be taken in the shade to be accurate, as long as the sun is not directly on the

temp gauge should be OK, I have mine mounted on a small wood shelf attached to the water

tray with 5 sides covered and one opened

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