Dendrobium flask temperature

[dendroboii]

Hi,
I have a question regarding flask care. So last week I did my first flasking. I sowed seeds from some Dendrobium pods, which the parental plants grow well in my small outdoor garden. My place is very hot and humid all year long (temperature reaches >33 oC in the afternoon and 27-ish at night). It's been around a week and no sign of contamination has appeared.

My problem is I have very limited space to store the flasks inside, so I keep them on the balcony, with 11-12h indirect sunlight. The temperature, as described, can reach 35 oC. So I'm just wondering if this range of temperature will affect germination and growth.

I've read that the ideal growth is achieved at room temperature (25 oC), but some people also say the temperature which the parental plants grow at. I need tips from someone with Dendrobium flasking experience. I have some more pods ready to sow, so just making sure I'm doing the right steps. Thanks!

[estación seca]

Welcome to the Orchid Board!

I have no experience with flasking Dens but I think your outdoor temperatures will be fine if you keep them out of the sun.

[Mr.Fakename]

There's no consensus about the best temperature, as it depends a lot on the plant and the experiment.

The good thing is that they'll already be acclimated to your temperature range when you deflask them.

I agree with ES, no full sun or the seedlings will get toasted.

If I were you I'd put cling wrap around the vessels to limit air movement; the temperature difference between day and night can cause pressure difference between them and the exterior, and if the flasks deform, contaminants can get in.

[dendroboii]

@estación seca Thanks, literally the reason I joined the OB was to find some tips on flasking. Yes, my flasks are out of the sun.

@Mr.Fakename Thanks, I did put plastic wrap around the lids for the same reason, and it's been a week with no contamination occurring so I guess wrapping works.

[SouthPark]

Originally Posted by Mr.Fakename

If I were you I'd put cling wrap around the vessels to limit air movement; the temperature difference between day and night can cause pressure difference between them and the exterior, and if the flasks deform, contaminants can get in.

Sounds good MFN.

So the cling wrap adds a bit of a barrier that can stop contaminants from getting in under those circumstances, while still allowing for gas from the flask to escape when needed?

[Mr.Fakename]

It does act like a barrier, but is a bit of a double-edged sword.
It keeps pathogens out of the flask, but should be avoided when possible, because it stops gas exchange.

For some plants it causes a problem; due to volatile compounds (like ethylene) and/or imbalances between oxygen and carbon dioxide, growth can be stunted.

That said vented caps are expensive, and gas exchange isn't too much of an issue for seeds germination. Plus, frequent replates put plantlets in "fresh" air.
Cling wrap is a good DIY option to increase success when you don't have a lab.