Greenhouse temperature - how hot is too hot?


Recommended Posts

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!

Link to comment
Share on other sites

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?

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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).

Link to comment
Share on other sites

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

Link to comment
Share on other sites

  • 3 years later...

I want to grow Venus flytrap, but I don't correctly organize its content. I read that she must live at a temperature of 35C, and to provide such a temperature, I want to put her air conditioner. I have already taken it to the diagnostician from https://hot2coldairconditioning.com/air-conditioning-repair-holiday-fl/. But I don't know where to place the air conditioner and whether the direct flow of air will not be harmful to the plant. Please tell me who has experience with this plant, how to keep it properly with air conditioning.

Edited by caraton
Link to comment
Share on other sites

I don't know where you read the Venus Fly Trap needs 35C to grow as this is simply incorrect.  A regular Venus Fly Trap (Dionaea) does not need 35C to grow, in fact this may even stress the plant if continued for too long.  Many of us let them drop to 0C or just below 0C in winter in an unheated greenhouse and this low temperature rests them.  During the growing season they may get up to 35C but that is not necessary as they will be perfectly happy in the 15 - 30C range.  They also need humidity and they should be kept in about 1 - 2cm of rainwater at all times except when it is below about 5C.

Check out any carnivorous plant nursery for detailed growing conditions for Dionaea muscipula.

Kind regards, 

Rob

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share