Potting large Cattleya in low humidity? - Orchid Board

gdupont · #1 05-01-2020, 05:03 PM

Hi all,

A few weeks back I posted about a Cattleya I was thinking of purchasing, a C. gaskelliana, which I ended up going for! It's awesome, quite large, and it looks very healthy.

The plant came from SBOE, which I assume must have pretty humid greenhouses, as the plant arrived with no media besides a few small chunks of granite from the seedling pot.

I'm wondering how I should pot this up at my home (in New England)? My humidity indoors is only around 40% which is lower than I would like (it will go outside when it gets more consistently warmer), so I think it needs a mix that's a bit more water-retentive, while still being fast-drying. Right now, temporarily, I have it in a slightly larger pot, only half-filled with some new orchid back mix I had available (open to finding a new mix for it online). I don't want to smother the roots, especially if they're used to open air. Am I think about this right?

Right now I'm thinking of getting a bark mix with larger chunks (extra-large?) and maybe throwing in a little bit of sphagnum? Also, probably a smaller pot?

Open to any/all ideas! Images attached.

Thanks!

ghuylar · #2 05-01-2020, 05:10 PM

I wouldn't use sphagnum moss with catts, have had nothing bud bad experiences with it over here in WA! Which is saying something because I am a HUGE proponent for the use of sphag. Catts really don't like their roots to stay wet for very long at all, a nice chunky bark mix should do you well

also 40% humidity is perfectly fine, I have found that plants generally care more about being watered correctly than having a humid environment. Happy growing!

---------- Post added at 01:10 PM ---------- Previous post was at 01:08 PM ----------

Also remember to leave enough room in the pot for 1-2 years of new growth! That larger pot you show should do wonderfully! And PS. the pbulbs look quite shriveled, it may be time for a thorough soak!

Roberta · #3 05-01-2020, 07:10 PM

I'd suggest large orchid bark. Personally, I like baskets rather than pots for Catts... they really do need to dry out between waterings. How you achieve that under your conditions probably is different than under mine.

Just a bit of insight about SBOE conditions... they are located only a couple of miles from the coast, climate is moderately humid and very temperate. I would suspect that this plant actually lived outside in a covered shade house (you might ask them whether it was grown in the warm greenhouse or not) Their technique of using rocks as a medium works great for them (I suspect they water a lot), I have found that their plants (I have bought a lot from them) do better in bark for me. Their technique for most Catts is to start them in pots with medium, then as they outgrow the pot they just drop the whole thing into the next size pot, and once the plant gets beyond seedling size, no medium at all - the space between pots seems to provide enough humidity. I have had plants from them with 5 pots of increasing sizes (sort of like one of those Russian dolls). Again, I end up with bark doing better for me, but continuing with lots and lots of air.

gdupont · #4 05-01-2020, 10:04 PM

Thanks so much, ghuylar and Roberta!

ghuylar – I'll be sure to avoid sphag! Good to know about the humidity vs watering point, I'll keep that in mind. And glad to hear the pot size looks right!

Roberta – thanks for all the advice! The basket option is interesting, I imagine that in low humidity that would require at least daily watering? I chatted with Wayne & Alice about the plant a bit when I purchased it, they mentioned it was kept in the cool greenhouse. I'll go for the bark!

Roberta · #5 05-01-2020, 10:12 PM

Quote:

Originally Posted by gdupont

Roberta – thanks for all the advice! The basket option is interesting, I imagine that in low humidity that would require at least daily watering? I chatted with Wayne & Alice about the plant a bit when I purchased it, they mentioned it was kept in the cool greenhouse. I'll go for the bark!

I water my outdoor Catts about every 2 days in summer, every 3-4 days in winter. My humidity is a little lower than Santa Barbara, temperature a little higher in summer. Catts, especially robust ones like yours, really don't want to stay wet, have plenty of reserves when they dry out. Maybe if it's triple digits F. they could use daily watering as much for cooling as hydration, but otherwise not so much. (I'll water the little mounted Sophronitis every day, but those are distinctly different if if they are now called "Cattleya")

gdupont · #6 05-02-2020, 02:46 PM

Follow up Q! Going to try soaking this one to rehydrate it a bit -- how long should I be soaking it for? Thanks!

Roberta · #7 05-02-2020, 02:52 PM

I don't think it needs any special handling (based on my experience with similar plants from the same source) Back bulbs will just be shriveled. That's what they do. (Back bulbs also probably don't have a lot of roots, also what they do...) Getting some bark around the new roots will keep the plant happy... and any new roots will grow into it. But from what I have seen, too wet is far worse than too dry. (Mine seem to really hate pots)

gdupont · #8 05-02-2020, 03:08 PM

Got it, thanks Roberta!

I got a Cattleya lueddemanniana from orchids ltd about a month ago, it came with ~9 bulbs in a 5 inch pot. I was watering twice a week (no soaking), but two weeks in the leaves of all the youngest pseudobulbs turned yellow and all the other pseudobulbs started shriveling. I was assuming it was from underwatering due to the shift in humidity.

Maybe that wasn't the case, though? Instead just part of the plant transition and acclimating?

isurus79 · #9 05-02-2020, 03:22 PM

Cattleyas don't need high humidity and 40% is fine. Cattleya lueddemanniana is actually from very desert like parts of South America. Losing old leaves on a Cattleya is not a big deal, but losing new leaves on a Cattleya is very troubling. You should always soak your plant every time you water. Maybe bump it up to 3x per week?

Roberta · #10 05-02-2020, 03:47 PM

Quote:

Originally Posted by gdupont

Got it, thanks Roberta!

I got a Cattleya lueddemanniana from orchids ltd about a month ago, it came with ~9 bulbs in a 5 inch pot. I was watering twice a week (no soaking), but two weeks in the leaves of all the youngest pseudobulbs turned yellow and all the other pseudobulbs started shriveling. I was assuming it was from underwatering due to the shift in humidity.

Maybe that wasn't the case, though? Instead just part of the plant transition and acclimating?

I'd be inclined to take it out of the pot and take a look at those roots. That will tell you whether it is underwatering (probably not) or bad roots (more likely)... if the latter, fresh medium will go a long way toward starting it back to health.