Yellowing while developing sheaths

[Ray]

As orchids go, most inflorescences are very fast growing, compared to the rest of the plant. That means a lot of nutrients are being funneled to those tissues.

My first thought was that you should try Epsom Salts - a single watering with 1/8 teaspoon/gal ought to show some greening shortly.

Then it occurred to me that they might be drying out rapidly, so the absorption opportunity is fleeting. If that's the case, watering more often at the current fertilizer concentration might be the key. ES' observation supports that. Alternately, you might consider "upping" the fertilizer a bit - maybe 50% more than the current amount. There is no danger of overdoing it at such rates.

A few questions:

1. What is your water supply?
2. How long have the plants been getting the current feeding and watering regimen? (I know it hasn't been very long.)
3. What were they getting previously?
4. Are you using KelpMax more frequently than monthly or at a stronger concentration than 1:250? (Incidentally, there is no issue with applying it or Quantum with fertilizer, or all three at once.)

[Steve83]

ES, yes I've checked leaf temps, and keep broms at the warmest area as an indicator of sorts.

The aurantiaca has been doing great as far as hydration, and the old bulbs haven't displayed any shriveling. I do plan on mounting it once flowering is done, so I can get more air to the roots, and have one less pot to deal with.

---------- Post added at 01:08 PM ---------- Previous post was at 12:06 PM ----------

Ray, I fed some P and K last night, and will add some epsom salt to today's waterings.

1. RO city water, with dechlorinator added. I check ppm on every 5gal fill up, and its fine.

2. approximately 45 days

3. The Dinema and Epc were fed MSU weekly at a higher ppm than I fed. I also mounted the Epc about two weeks ago becasue It wasn't breathing well in the pot. Its older bulbs are better hydrated thatn when I purchased. I don't know the prior culture of the aurantiaca.

4. KelpMax has only been applied monthly at 4ml to 1 Liter RO water.

My watering consists of spraying the roots of the all the mounts first for a few seconds, hitting the potted stuff, spray mounts again, spray broms, spray mounts.

This occurs at 8:00am, and is often followed by another watering later in the day with what is left in the sprayer.

I decided to create a set schedule in google calendar last night, so every supplement/nutrient, and it's mix ratio is pre-planned, and repeats per instructions.

I am going to give additional amounts of Mg, P, and K over the next few days to see if this subsides

I can't imagine Ca is the issue, as things that are growing quickly, display no typical signs of Calcium deficiency. These Myrmecophila pics are dated 9/15/20 and 10/6/20. Note how plump the old bulbs have gotten, in addition to the new bulb growth.
Myrmecophila9/15.jpg - Google Drive

Myrmecophila10/6.jpg - Google Drive

All the broms have been pupping as well, and show no signs of deficiency, just lots of red lol.

[Nexogen]

The plants look good but some of them may be infested with spider mites.

[Steve83]

I checked all the plants, and no spider mites.

I have some positive updates.

Light intensity, somewhat, by covering the opposite side/corner in poly sheeting. I also divided and unpotted some broms, and attached them to some plastic mesh I zip tied.

plasticforest.jpg - Google Drive

With what I was seeing among my plants, I believe I have narrowed the deficiency to Mg, P, K, or some combination.

Interestingly, my Onc. Twinkle Pink Profusion, which was purchased with one spike in early September, produced another early last week. The stem on the second spike is noticeably larger in diameter.

OncTwinkle.jpg - Google Drive

Yesterday, I noticed it was finally starting to show some yellowing as well, and to my surprise, I found two more spikes forming (both of larger diameter).

Since this was first reported, waterings have been with K-Lite @ 25 ppm N with either P and K, or Mg added.

All of those listed have begun to slowly green up. I'll continue with this regimen, and keep my fingers crossed.

Even if things resolve, this layout isn't ideal for repeating on the opposite of the tent becasue it's just too cramped. I most likely will have to bump up to a 4'x4' tent with a height extension before adding anything else.