Watering/Feeding Indoor Mounted Cattleya Seedling

[galguibra]

First time posting on here after recently getting my fist ever orchid!! I took a look through the guide, but feel free to let me know about any norms I might've missed or if I went into too much detail. I wanted to make sure there was enough detail that people could confidently weigh in without needing too much immediate expansion/clarification, but I realize this turned into a bit of a full-length thesis along the way . Thanks in advance for any advice you all can provide!

TLDR, I'm new to orchids and was hoping to get some guidance on watering and feeding a mounted Cattleya seedling I just got earlier this week, but here's a full context breakdown in case it helps:

Specimen: Cattleya intermedia v. aquinii fma. coerulea

Seller: Louisiana Orchid Connection, link here

Size/Age: Came in a 2" net pot, but was definitely outgrowing it. Roots had already come out through the bottom and sides into the cache pot. Not sure how old it is exactly. See picture below for how it looked on arrival:

Mount: Cork bark flat, ~14"x5" average dimensions. Attached bare root and inverted using 2mm rubber-coated floral wire, and nestled into a slight hollow in the mount. I tried to position the new growth so it could climb up the mount, but I also wanted make sure everything could drip dry as easily as possible and keep water from getting trapped anywhere and causing rot. See pictures below (very recently watered in both images):

Full View:


Close-Up:

Growing Conditions: Hanging on the wall in my bedroom near an automated cool-mist humidifier and some other tropical plants, far away from any vents.

Humidity: The humidifier is set to keep the humidity between ~60%-65%, although it sometimes drops to ~50%-55% if the AC is running particularly hard due to the weather. Peak output is ~300mL/h, but it'll adjust as needed.

Airflow: I have an air circulator running 24/7 rated at ~512 CFM. Room volume is about ~1161 cubic feet, so it should do the whole room in a little over two minutes. I have the fan on a bookcase pointed up at the ceiling corner behind all the plants, so the air comes down and around to give them a gentle breeze. You can feel it, but even the thinnest leaves on any of the plants only just barely sway.

Temperature: It's starting to get pretty hot in Chicago, but I still wanted a nighttime temperature drop for the plants, so my HVAC is set to 73°F during the day and 68°F at night. The central fan also circulates air for 15 minutes every hour just to keep things fresh.

Lighting: I have the mount under a full-spectrum (380nm - 800nm, 6500K) LED grow light, and it's calibrated to run at ~200 PPFD on a 12h/12h timer—the same schedule as the HVAC. DLI comes out to ~8.5, and the lamp doesn't give off any noticeable heat at all. It's still like 16" away since I wanted to take it slow on a new plant, but I can definitely up the light as it grows!

Everything above I took as a starting point based on experience with other (sub)tropicals, so hopefully that makes it easier to advise on watering and feeding, which are the main things I'm really unsure about. That being said, any feedback on the growing conditions and stuff is also very welcome!

Also, I should note that when I unpotted the seedling, I did find a millipede in the bark chips. I wasn't sure if it was the detritivorous or herbivorous kind, but probably not a good sign either way. There wasn't any obvious damage to my untrained eye, but just to be safe I gave the roots a quick dip in 0.75% hydrogen peroxide to help clean them off without risking too much oxidative stress. This is also part of why I chose to mount bare root, in case anything else came up and needed quick attending to. See below for a picture of the unwelcome guest:

All of that out of the way, this is what I've been trying so far:

Water: I spray with distilled water at room temperature whenever I see that the velamen is looking thoroughly silver/white, and that the leaves and the base of the plant near the rhizome have had a chance to just dry off. This has been maybe ~5x a day so far, and I spray until the roots are green all over and the mount is lightly dripping.

I chose not to mount with sphagnum so I could keep an eye on the roots and give them lots of air, but I might add some if the watering burden gets to be too much or if I need to be away for a weekend or something. I tend to be a bit of an overwaterer and I know that's extra problematic with orchids, so I figured bare root might be safer for me unless in turns out the seedling really can't handle it.

Fertilizer: I didn't really want to be regularly soaking the whole mount if I didn't have to—although I did give it one thorough soak before actually mounting the seedling just so there'd be a little something to encourage growing onto new areas in the future—so I figured organic fertilizers applied as a spray might be easier to work with for now. Maybe I could do occasional soaks with inorganics once more of the mount is actually getting used? Open to feedback there for sure.

I also didn't want to go out and get specialty fertilizers for each of my different plants, so I've been mixing up nutrient solutions myself from component concentrates based on research I've done on each of my plants. My current approach is to feed once daily with a really dilute solution at ~25ppm N, with the rest of the concentrations coming directly from the manufacturer's directions for applying on orchids. I always pH the solution to 5.8-6.2 before applying, and only one watering per day has any fertilizer in it at all: the rest are all just plain distilled water. If it would be beneficial to buffer the water, I also have a seaweed extract that I could use on its own, as well as a 3-1-2 inorganic fertilizer with micronutrients, but I haven't used either on the orchid so far.

I've seen a lot of conflicting recommendations on fertilizers in particular (MSU vs K-Lite archetypes, dilute daily vs relatively stronger weekly feedings, etc), but for now I've been working off the concentrations for K-Lite as a starting point. This is what I have so far:

• Cal-Mag OAC (Organic Acid Complex), link here:
  

  
  

  • Concentrate is 4% available Ca and 1% available Mg (w/v)
    
  • Also has Fe, Mn, Zn, B, Cu, S
    
  • I dilute this one to 0.80mL/L, which comes out to ~32ppm Ca and ~8ppm Mg. This was the concentration given by the manufacturer for orchids specifically, but, for comparison, diluting K-lite to the same 25ppm N would give you ~20.83ppm Ca and ~6.25ppm Mg, which is pretty comparable but still definitely less concentrated.
    

  
  

• N-Primer (Slow-Release Large-Molecule Nitrogen Complex), link here:
  

  
  

  • 3.3% available N (w/v). 0.1% is ammoniacal, and the other 3.2% comes from other water-soluble organic complices
    
  • I dilute this one to 0.55mL/L, which gives me ~18ppm N, since there's also some coming from the next nutrient in the list
    

  
  

• Root Boost, link here:
  

  
  

  • This one is an organic C-P complex with liquid microbes/myccorhizae and a blend of "humic, fulvic, amino, and other organic acids complexed with extracts from 9 species of sea plants" (from manufacturer description). It has all kinds of natural plant hormones like you might find in seaweed sprays, plus all the other stuff listed. Plus it smells like chocolate!
    
  • The N-P-K is 1.4-3.2-0.7, and I dilute it to 0.50mL/L, which yields ~7ppm N, ~16ppm P, and ~3.5 ppm K. That rounds me out to the 25ppm N I'm shooting for, and is coincidentally also just under the manufacturer recomendation for orchids, which is ~0.53mL/L.
    
  • I confirmed with the manufacturer that this one doesn't have any auxins like IAA/IBA/NAA or any PGRs, since I saw on a forum somewhere that those can sometimes lead to deformities in orchids.
    

  
  

• Silica Gold, link here:
  

  
  

  • This one I only plan to use occasionally as a Si supplement, since it also adds an additional 1.3% (w/v) available K into the mix that I'm trying to avoid. It's a really cool formula though, and it also includes chalconoids, which stimulate synthesis of compounds that deter aphids/mites/etc; lots of amino acids and antioxidants; fulvic acid; and salicylic acid, which all help reduce stress, increase nutrient uptake and tolerance of drought, strengthen cell walls, etc. You can read a white paper on it here!
    
  • It has 3.0% (w/v) bioavailable Si in the form of silicic acid and other organosilicates, so I dilute it to 1.30mL/L, which is ~39ppm Si. This also adds ~16.9ppm K though, which why I'm only planning on applying maybe 1-2x/month.
    

  
  

So, to summarize all that, the fertilizer mix comes out to about 25ppm N, 16ppm P, 3.5ppm K, 32ppm Ca, and 8ppm Mg. For the 1-2x monthly that I plan to use the Si supplement, then I'd have 20.4ppm K instead on those days, plus the 39ppm Si. The distilled water itself has about ~10ppm TDS to start, and the rest of the micronutrient minerals in the Cal-Mag come out to ~0.896ppm, so in total we'd be looking at ~95ppm most days, and ~151ppm on the 1-2 days a month with the extra supplement.

Based on what I've seen researching online, it seems like a reasonable amount to me, especially since almost none of it is in the form of ionic salts and most everything is in some kind of organic complex or polymer. Would love to hear people's opinions on this mix/schedule though, since I realize it's not really standard. I try to apply it either early in the morning before the grow lights come on or shortly before they turn off for the night to maximize absorption and make sure the plant has time to dry off, which means the rest of the daily waterings should also flush any excess.

Thanks to anyone who's read this far in (I realize that was a lot of information all at once ), and I'm really excited to be starting my orchid journey with you all!

[Ray]

First of all, welcome aboard!

Wow! You have really made this a lot more complicated for yourself.

It appears you have mounted the plant upside down; they are not pendulous in nature. It will slowly correct itself with new growths, but that will take a while and may look ungainly.

You should place that newest growth up against the mount so that its roots will emerge near it. Adding a small pad of sphagnum over the roots will help extend the moisture retention.

I like your idea to mist and feed regularly, but it seems like an awful lot of work to mist the roots 5 times a day and I question whether that is workable, long term. With the suggested moss pad, a decent wetting once a day might suffice.

Orchids are very undemanding of fertilizer, and are very slow growing among plants in general. A plant only needs 5g of NPK to add a pound of mass, and for that plant, that'll likely be 4-, t-, or more years, and the most important nutrient is nitrogen.

It is the mass of absorbed fertilizer that’s important, and you must recognize that as you have it now only a few ml of solution are being captured. If you guess at the thickness of the velamen (I’ll bet it’s about 1 mm) and multiply that by the surface area of the roots, you can estimate the volume captured when you saturate the roots.

Most experienced growers pick a fertilizer formula they like and apply it regularly and sparingly. Changing formulas is of no benefit. The only plants proven to have a benefit from silicon are grains like rice.

I feed once a week @ 100 ppm N using K-Lite, which is a 12.9-1.3-1.3 formula containing 10% Ca and 3% Mg. Those last two are essential if your water supply does not contain enough.

With some adjustment to make sure the mass of nitrogen is enough, but not overdone, your regimen will be fine, but is a lot of effort for no particular gain, in my opinion.

[rbarata]

Welcome galguibra!

Considering the investigation you made for this orchid, you are risking burnout when you get the 2nd one.
Things don't need to be so complicated.

One thing I noticed is the peroxide on the roots. That's a no-no as it might damage (or even kill) them, especially that they were transplanted into another medium (pot=>mount). So, anything that messes with the roots in this more or less critical stage, it's better to be avoided (even peroxide in low concentrations).

I'm also not sure if this is the right season to change it because the already existing roots are not acclimatized to the mount. That's why an operation like that (or repot) is better when new roots start to grow as they get already acclimatized to the new medium.

[Roberta]

Just to reinforce what Ray said about orientation... The plant hasn't been on the mount long enogh to establish, so remove it, move it up on the mount, point it upward, and put the new growth next to the mount. It appears to be actively growing and rooting, so it's a good time for the mounting - only the new roots will grab the mount. The others just need to be kept moist to maintain the plant. That's where a bit of sphagnum over the top of those roots will help. But definitely you don't want sphag between the plant and mount So mount it sothat it is held in place firmly (vitally important that it doesn't move, since those fragile new root tips are easily damaged. Than add the overlay of "keep it moist" moss.

You are definitely making it 'way too complicated! Of all the cultural factors, fertilizer is the LEAST important. (Think of fertilizer as vitamins not food... green plants make their own food by photosynthesis.) Get everything else right, and give it a bit of fert of any sort, it'll be fine.

As far as watering frequency goes, think about what happens in nature - relatively humid but variable, it rains and then it stops. So it has evolved to handle drying out between waterings. (That is why it has pseudobulbs, and also a "waxy" cuticle on the leaves that reduces transpiration - and makes foliar feeding useless)

[galguibra]

Oh damn, I really thought I had oriented the new growth up toward the mount the right way around!



There are two pseudobulbs that I can see, and the larger of the two had a few new roots starting to come out of it, so I tried to mount the seedling with that pseudobulb and the new roots facing toward the top of the mount so it would grow in that direction. The mount kinda has a bit of a hollow toward the bottom there too, and the shape of it is angled up and to the right, so I wanted to make sure it could lie relatively flush and still benefit from having that hollow to conserve a little moisture and allow some extra airflow around the plant.


I recognize that sympodial orchids generally grow in a line as well, so I wanted the new growth to be close to that "ramp" on the left side, since it looked a lot easier to grow and climb up that way than up against the "shelf" toward the middle and right side of the mount. I don't know if that actually makes sense, but it seemed reasonable at the time haha.



Also, just to clarify and avoid having to do any further repositioning, what direction should it actually be facing? Not trying to be obtuse but like, if the position it's currently in (larger pseudobulb on the left, leaf openings facing as they are, etc) is 0°, how far should I rotate it and in what direction? I've seen people say things like "next to," "facing," or "closest to" the mount before in their mounting guides, but I'm not totally clear on what that means since the whole thing is more or less flush to the mount.


Are we talking like a quarter turn to the right with the larger pseudo bulb literally on top, or literally 180° with it on the right side instead of the left and the leaves pointing in the opposite direction? Any pictures I've found online of the species growing on native trees kinda seem to have growth going in all directions, so I'm confused about what exactly I should be looking for, especially since this one started out in a pot growing straight up.


Thanks for all your advice so far!

[Roberta]

I am seeing a strong new growth that is closest to the camera - there may be another one, that shows better in the original photo from the pot. So I'd flip the plant 180 degrees in the plane of the current mount, and then flip it 180 degrees in the other plane (so that the strong new growth is against the mount and the opening is pointing upwards. The sympodial growth will continue in that direction, but you also need to allow room for the roots to grow downward. The "upside down" part doesn't concern me much... in nature than can grow rather horizontally. But at least the way it looks now, in time the rhizone will tend to grow away form the mount. Now, could be wrong.. I have had plenty of plants where I have guessed wrong and have had to remount - or, when it goes in more than one direction, I end up plopping the mount in a pot. So this is just a guess... hard especially to translate a 2 dimensional photo to a 3 dimensional plant. No worries... just observe what it is doing, and adjust accordingly. What you really want to look for is new little root nubbins that haven't even broken through yet, those are the ones that will grab a mount, or adjust to new medium. Personally, I think it would be a whole bunch easier to put in a pot (the oldest part against the edge to maximize room to grow). use medium bark in a 3/4 inch pot and again, just observe. C. intermedia is quite forgiving of temperature range (I grow it outside in southern California where it can get close to frost and summers into the 90s F) For you, if you can put it outside now (dappled sun or bright shade) , and just bring it inside when fall temps head for the low 40's F. It will love that Chicago summer humidity that people hate.

---------- Post added at 01:51 PM ---------- Previous post was at 01:17 PM ----------

Another thought... I have found that wood baskets are great for Catts, think of them as a "three dimensional mount". The roots go wherever they want to, seem to like the wood. (Plastic baskets work OK too but the ones I have in wood baskets seem to grow better for me). You can start it in a 4 inch basket, when it outgrows that just pop the whole thing into the next size, likely won't even have to add medium by that time, it'll be growing like a mounted plant. But in general...just relax and observe. you'll learn what's really important and what isn't in the way of the advice you'll find. (Orchids don't read...) Your choice of a species to start with was excellent. You'll find that you can get away with a LOT.

If there is an orchid society near you, that's a great way to get local knowledge, and a lot of willing help. (Most orchid hobbyists LOVE to talk orchids and help new growers)

[LexaCat]

Following up on Roberta's suggestion to check out your local orchid society - the Illinois Orchid Society is a warm and welcoming group of enthusiasts that holds most of its meetings and shows at the Chicago Botanic Garden just north of the city. Perhaps you have joined already?

Illinois Orchid Society

[rbarata]

Originally Posted by Roberta

I am seeing a strong new growth that is closest to the camera...

Is there a photo? I can't see it.

[galguibra]

Oh that's great to hear about the IOS! I don't have a car, so it's ~2hrs to get there on a few different trains/buses, but for a monthly visit or so it could be a fun little adventure I'll definitely have to look into that, so thanks for the suggestion!


Also, if I'm understanding correctly, that combination of rotations would end with the leaves opening up toward the ceiling, and the concave part of the larger leaves on the pseudobulbs facing toward the mount so that someone standing in front of the mount would see the undersides of those leaves. Is that what you meant? I'll attach some different angles in case that makes it easier to visualize!

[rbarata]

Just a tought...instead of rotate the plant, isn't it possible to rotate the mount?