Papilionanthe 'Miss Joaquim '
 

Before and after photos show some black spots that have developed on the plant. Anything to worry about? Kept in a grow tent under very bright light. Temps range from mid 60s to mid 70s. Humidity averages around 50%. There is good air movement in the tent.
https://i.postimg.cc/dZYXL7Xb/20210920-074809.jpg

https://i.postimg.cc/XGFmjK2K/20220119-112133.jpg

I don't see your photos, but the ones I've seen growing outdoors in Florida have lots of black spots. Mine in my sunroom has lots of brown and purple spots. I know I'm not fertilizing enough.

Duh! Forgot the link. Posted now.Thanks, E.

Now I see the photos. Your plant has fewer spots than mine. :crackup:

How do you water it, and how often? The spots appear to be mostly on old leaves at the base. It is a warm growing plant. Mine does OK with winter nights into the upper 40s F / 6-8C but I think that's because the next day is always a lot warmer. It doesn't burn in summer even with direct sun through the glass. I think it would tolerate my outdoor summer temperatures but not the low humidity.

I need to figure out how to fertilize mine more. It flowered last winter but has no spikes now, though it's a lot larger. I lay it horizontally in an area watered with a daily spray. It has grown wandering through adjacent plants, but it doesn't have that many roots.

As I said, it lives in a tent. I soak it and the mount with a spray bottle everyday. Every other day I use a 100ppm nitrogen fertilizer in rain water. Once a month I give it a Kelpmax bath for about 20 minutes.

For what its worth in Singapore they dont grow this plant mounted really. In gardens here they grow it in a charcoal base, and just tie it to fences in long rows. In the NOG they dont even put them in the ground, they have metal stakes about 6 feet tall with wires running between them to form a fence like structure and then just tie them to the wires with nothing in the ground. No mounts or anything for the roots to grow into. I wish I had taken more photos of how they cultivate it when i visited the NOG. I think I will take my nephew there again before I leave so I will take some detailed photos for you when I do. I did however take this photo of an information board:

http://www.orchidboard.com/community...1&d=1642652433


FWIW It grows to about 8-9 feet tall before it flowers and the usual advice here is that it wont flower until it has grown about 3 feet above whatever it is tied to. They like to grow lots of them closely grouped together here and when they are blooming it makes for an incredible display and a relatively attractive "green" wall effect.

The Singapore Botanical Gardens people were very helpful when I emailed them for advice on how to treat my dying plants in Amsterdam. I have unfortunately managed to kill three of them so far, one after it got to waist height (from a clone). I just purchased two new clones when I visited the NOG (National Orchid Garden) and im going to try again this year, but I will have a greenhouse to grow it in instead of my living room (way too low humidity)

They want high humidity and they can handle direct equatorial sunlight just fine. Small black spots on the leaves are common from the heat.

I would guess you are over-treating it. I doubt if they fertilize the ones at the NOG very often. They just spray them down with a hose at least daily, on top of whatever rain comes down. They definitely don't use kelpmax. FWIW. If I visit Toh Gardens ill ask someone to look at your photo and tell me what they think. My bet is they say "higher humidity, but it looks fine, although whats with the wood?" they dont grow them mounted in Singapore as they are a half terestrial orchid actually, and can grown in dirt or sawdust. :-)

They grow like weeds in Singapore, which is so frustrating when I consider that I have managed to kill three of them so far in my Amsterdam apartment. Here are my two new baby plants still in SBG/NOG packaging. (14 SGD, about 10 USD, a bit expensive, I could buy a flask with 250 of them in it for about 50 USD, but I don't mind supporting the SBG and what am I going to do with 250 9 foot tall plants in an Amsterdam house?)
https://www.orchidboard.com/communit...1&d=1642667300

I grow Papilionanthe teres (one of the parents of Miss Joaquim) outside on my patio - so while it would rather be warmer, it still does OK. It gets lots of water (aerial roots don't lend themselves to potting) and reasonable humidity, bright light but not direct sun. So.. for what it's worth, an indication of what one can get away with when deviating from the ideal. I have seen Miss Joaquim growing well in other people's yards in my areas, I think it may be even more forgiving than the species.

I received this as a cutting from a large plant in Asia. It was collected legally by the vendor who gave it to me. The "wood" is a piece of tree fern fiber the vendor attached it to for convenience. One root had grown through the block and is still viable. I kept it this way for the convenience of hanging it. During summer it resides on my deck in full sun (zone 10a) and I water it with a spray bottle, also for convenience, and because it is a long stretch from the hose bib.

No worries about the provenance of Papilionanthe Miss Joachim ... it's a hybrid. And widely grown. A delightful vigorous plant!