Question about outdoor s/h during winter
 

I live in SW Florida so our winter temps don't get too low but we occasionally drop down into the 30s and 40s overnight. I currently grow some of my Phals in s/h and they love it. I normally leave them outside year round and bring them in if the temps get below 50. It doesn't seem to hurt them and they reliably bloom for me late winter/early spring.

Anyway, I know that the s/h does bring the root temps down which isn't a problem for most of the year and so I'm trying to plan for this winter so I can make sure they continue to thrive. I was considering getting a seedling mat for them to sit on so that the root temps don't drop too low but I'm wondering if that will be enough.

I transplanted the three I have in s/h in December/January this year when they started new root growth and they were outside when I did it and didn't seem to suffer any ill effects. However, our winter is mostly over by then so I'm wondering if that had anything to do with it.

While I'm here I guess I should ask about my Paphs in s/h, too. Should I consider a seedling mat for them, as well?

Thanks, everyone!

In my experience, phalaenopsis hate cold, wet roots. Leave them out over winter (anything below 65° in my opinion), and you'll be shopping for new plants.

Paphs are more tolerant, but I never let any of my orchids - S/H or not - get into the 40's.

I'm with Ray on that one. I do S/H and never let the warm growers get below 60f for any prolonged time periods. The occasional Whoops! down to 50+ occasionally happens, but I wouldn't want it to happen often. A seed mat would help with the root warmth to an extent, but not be enough for the rest of the plant.

The only thing I let hit the 50s mark and stay there for awhile are the Cymbs.

Thanks, Ray and WaterWitchin!

I wasn't sure if seedling mats would work for over the winter so I guess I'll just bring them indoors for the winter. I'll just have to try to find a place where the stupid cats won't get to them because one likes to eat everything.

Edited to add: I think I'm going to switch them back to traditional media. They're roots are still actively growing and I really don't have any place in the house I can keep them safe. I'm glad I asked early so they shouldn't have too much of a setback if I do it now.

Don't know about Cyms in S/H, never tried tried it. But in normal bark media, they're fine down to about 30 deg F (assuming it warms up a bit once the sun rises). (You might get some bud damage much below 35 deg. F, but the plants will be OK, and very possibly the buds and flowers as well) See the experience of a major commercial grower: Ice in the Nursery
I can vouch for the robustness of these flowers - the flower shown encased in ice (32 def F)was in a show two weeks later, looking none the worse for wear.

Re Paphs:
It depends very much on which sub-genus you are talking about. The insigne group (& complex hybrids), can tolerate surprisingly low temperatures (45-50F). So can armeniacum & micranthum. However, I would not try anything lower than 55F for multiflorals (and Maudiae types).

The insigne group is even tougher than that... my Paph insigne, villosum, and hybrids (Nitens, Leeanum) grow quite well outside all year for me... occasional nights into the mid 30's F but not for many hours. I have also found that this group is happy with a bit more light than most Paphs. Paph gratrixianum grows with less light than the insigne group, but also is very cold-tolerant. (There are a bunch of others that don't mind the mid 40's F but suffer below that) Certainly agree that the Maudiae types and multiflorals need to be a lot warmer, I'd say closer to Phal temperatures. (But my growing is pretty binary... either it is outside or in the fairly intermediate greenhouse, a few things move for the winter but mostly it's one way or the other)

S/H in winter
 

Hi there,

How about the cooler growers like Zygos and Miltoniopsis in S/H during winter... does anyone have experience with these orchids?

To those making recommendations based upon your observations of temperature tolerance, do recall the question was about plants grown in semi-hydroponics. The constantly-moist but airy medium can lead to significant evaporative cooling of the root system, taking it several degrees cooler than the air temperature.

Chickzilla- that would certainly be the case in LA, and less so (though not none) for Barbie in southwest FL.