Need some help with my Renanthera monachica

[Ray]

OK. Time for a little "tough love", given in the hope you can learn from many of our mistakes, rather than repeating them.

First, you seem to have used the "shotgun approach" of acquiring plants you like the look of and hoping you can grow them, rather than learning what they want and making sure you can provide that. Pause a minute and do the latter, really analyzing your growing conditions and how you might improve them, then search for plants whose requirements match that. Master growing such plants through a few bloomings and then consider expanding as you gain an overall understanding.

You have a special challenge in your part of the world with lack of humidity. You really should consider improving that. It'll make life on your orchids a lot easier.

Stop moving plants from potting medium to S/H to potting medium to potting medium, hoping you'll find "the right one". It doesn't work that way (not well, anyway). The "trick" is to understand the needs of the plant and decide on the proper container and medium to provide that in your environment. Move it over and pamper the plant while it gets reestablished.

When roots grow, they "tailor" themselves on a microscopic level to function optimally in that environment, and once grown they cannot change. When you move them into another, different environment, they will be less than optimal, and may begin to fail. That's why it's always best to repot just as new roots are emerging from the base of the plant; those new roots will be optimal for that new environment, so will support the plant as the old roots fail. The greater the differences between old and new environments, that faster the old roots will die, and changing it multiple times just stresses the plant over and over.

Your renanthera wants very hot, very bright, and very humid conditions. Give it all three and it'll thrive in a basket with no medium (if you water it often enough), but I found that adding a mesh liner to the basket and adding coarse LECA did a good job of holding moisture around the roots while remaining very airy.

[OrchideeNormus]

Ray - you are absolutely correct about that 'shotgun approach' lol. When I first caught the bug, I bought a lot quickly. I also had no idea what I was doing! I have lots of experience with gardening so I honestly didn't expect orchids to be any different (go figure, beginner mistake eh &#128514 I even killed two phals in the beginning!
This is why now, I am trying to focus on each one and learn more about them so I can provide a better environment for them and hopefully keep an array of happy plants. I feel lucky that out of 19 only 4 seem to be doing poorly. One of them definitely was in bad shape when I got it and it seems to be on the upswing (Den phal from Lowe's, was completely dehydrated and looking sad on the shelf. Pitty purchase lol). The other three are likely my own doing.
I am working on how I will be changing things for summer growing, which should be much easier. And also what I need to prepare for next winter.
As far as switching them around from media to media, I do try and avoid that as much as possible. This ren is the only one that's actually been subjected to that because it reacted so badly in the s/h and didn't seem to get happier after the switch. I have since learned that this particular plant is extra slow to do anything but sulk. So I have been (trying) to be patient instead of trying yet another new method.
I really like your idea of adding LECA to the basket. Maybe I'll mix a little in with the moss so that way when the new roots do grow they will be tailored to that media and the transition won't be so hard on it if I do go that route. I'm soaking the basket right now and will do so for about an hour so all the wood is saturated. I'm going to start using this method on my christensonia vietnamica as well. I put it in a basket with moss and bark, I've had it a little over two weeks and is doing really well so far. I don't want to have the same dehydration ssues with it though!
Don't feel bad about tough love, we all need it from time to time 😉 I can take it, promise lol

[Fredmax]

A bit late to the discussion here, but I've also had challenges with Ren Bella, I purchased it from a Floridaesque climate while growing in a Mediterranean one myself.

I had the opposite experience in that it really struggled and immediately lost two lower leaves and settled once I repotted from bark to leca which it at least stopped dying.
The decider seemed for me to be the inability to provided constant hot temperatures, anything lower than 16-17 (around 60f) spells doom for this plant. Given that's the high we get during Winter here with lows around 4c/40f it seems like it will always struggle outside the summer heat.

It did well in the GH over summer with humidity but I can't provide the heat it needs in there over Winter,
so I'm resorting to now keeping in a kitchen window which won't provide it much sunlight unfortunately but won't subject it to the low temps.

Anyway this was an experiment to understand the Ren's thresholds, Vanda's do ok for me but this was a step up in requirements.

Would love to know how yours fared, for me the constant hot temps seemed the crucial element so assume yours must be doing better in the Spring climate.