Sun and heat frustration!

PaulDavidMc · Feb 1, 2026

I recently (six months ago) had a greenhouse installed but have found that during the Tasmanian summer it’s been getting too hot- even with the windows and door open on sunny days.

Many of the largest pitchers are burnt (not just natural die back) and some of the drosera capensis have been fried to a crisp - which is very disheartening.

I’ve put a shade cloth up which is helping but if anyone has advice on how to help the recovery process - other than time - that would be grand.

PaulDavidMc · Feb 1, 2026

What I have found interesting is that all the new pitchers are growing back slightly smaller than the ones which got burnt - almost as if the plant knows where the danger zone is.

stevebradford · Feb 1, 2026

Shade cloth for sure and added with a Swamp Cooler it might keep the temperature low enough and also humidity up.

Plant photosynthesis generally stops when leaf temperatures exceed 40°C to 50°C (104°F to 122°F), as high heat causes essential enzymes to denature and proteins to break down. Tropical species often see photosynthetic failure at lower temperatures, averaging around 46.7°C (116°F), due to severe leaf heat stress.

PaulDavidMc · Feb 3, 2026

As I’ve mentioned in other posts I’ve had to put shade cloth up in the glasshouse to try and cool it down a little and stop the sun from burning plants.

Today, I decided to remove various pitcher plants (and my VFTs) from the glasshouse and put them in shaded / protected areas of the garden.

My plan is to leave them outside for the rest of the summer to see how they travel. I’m thinking that if they do ok (I’ve no reason to think there will be any issues) then at the start of next summer they are all placed outdoors where they won’t overheat.

Please let me know if you’ve had to do anything similar.

Lloyd Gordon · Feb 3, 2026

In Canada we have many evil beasts who delight in savaging all sorts of plants, particularly ones that are expensive, rare or difficult to grow. Perhaps you are luckier in Tasmania, despite the Tasmanian Devils.

spiffyzha · Feb 4, 2026

PaulDavidMc said:
various pitcher plants

Do you mean nepenthes? Or sarracenia? (Or heliamphora, I suppose? Or all three?) Your nepenthes will certainly appreciate a bit of shade, though some are more tolerant of unfiltered sunlight than others.

For sarracenia, my understanding is that they really can't get too much sun, and as long as they're kept well watered they don't mind the heat either -- but also, it's entirely possible that I only think this because you never hear of anyone in Canada overheating anything in their greenhouses.

Lloyd Gordon · Feb 4, 2026

Actually, I often see people shading their greenhouses with whitewash around here.

PaulDavidMc · Feb 4, 2026

spiffyzha said:
Do you mean nepenthes? Or sarracenia? (Or heliamphora, I suppose? Or all three?) Your nepenthes will certainly appreciate a bit of shade, though some are more tolerant of unfiltered sunlight than others.

For sarracenia, my understanding is that they really can't get too much sun, and as long as they're kept well watered they don't mind the heat either -- but also, it's entirely possible that I only think this because you never hear of anyone in Canada overheating anything in their greenhouses.

Well, after my experience this summer I can promise you that sarracenia can get too much sun!

In fairness this is the first time I’ve ever had such a problem but I’ll be aware of it for next year and better prepared methinks.

Lloyd Gordon · Thursday at 12:52 AM

Toronto and Tasmania are at almost the same latitude so the sun's strength is much the same. However under glass, full sun, no ventilation, any CP will die. I've had Sarr's under full, direct sun all day, summer solstice, in a heat wave ~ 37°C and they were fine. Had to keep the water at the soil medium surface though.

spiffyzha · Thursday at 1:23 AM

Well, now I'm curious... any chance the sarracenia are actually suffering from the heat rather than the light? There's a limit to how bright the sun can "be", and there are plants that like it maximally sun-bright. But the limit to how hot a greenhouse can get is .... high enough to kill virtually everything.

On the other hand: something I noticed with my drosera is that they're much more prone to getting sunburns if they haven't been fed recently. My sarracenia get their own food though, and they never go hungry, so I haven't tried to test this on them. (Also, I don't have nearly enough light to do this test, heh.) But if your sarrs live in a greenhouse, maybe they don't have so many bugs lining up to do a death drop?

PaulDavidMc · Thursday at 1:30 AM

Lloyd Gordon said:
Toronto and Tasmania are at almost the same latitude so the sun's strength is much the same. However under glass, full sun, no ventilation, any CP will die. I've had Sarr's under full, direct sun all day, summer solstice, in a heat wave ~ 37°C and they were fine. Had to keep the water at the soil medium surface though.

Hi Lloyd, there’s ventilation plus along with open windows I leave the door open too.

PaulDavidMc · Thursday at 1:34 AM

spiffyzha said:
Well, now I'm curious... any chance the sarracenia are actually suffering from the heat rather than the light? There's a limit to how bright the sun can "be", and there are plants that like it maximally sun-bright. But the limit to how hot a greenhouse can get is .... high enough to kill virtually everything.

On the other hand: something I noticed with my drosera is that they're much more prone to getting sunburns if they haven't been fed recently. My sarracenia get their own food though, and they never go hungry, so I haven't tried to test this on them. (Also, I don't have nearly enough light to do this test, heh.) But if your sarrs live in a greenhouse, maybe they don't have so many bugs lining up to do a death drop?

Hmmm, I don’t think so - where I lived previously I had a glasshouse which got just as hot but we were on the side of a mountain and so the sun wasn’t as intense.

Plus, all the plants were fine until mid December which is when the sun really seemed to become an issue.

Lloyd Gordon · Thursday at 2:11 AM

You'd have to measure the temperature in the greenhouse. I suspect it would be pretty high in the summer. Sarr's grow in Florida where the sun is almost overhead in summer and the sun doesn't bother them.

stevebradford · Thursday at 10:16 AM

You might find this interesting. John a former member here from Adelaide south Australia grew some of the healthiest most impressive Nepenthes in his greenhouse year around.