Constant humidity vs Constant Irrigation

[Cach26]

hello
I want to grow orchids with Very, Very large pseudobulbs (Catasetums, Anguloas, Catleyas Lycastes etc), and I have this question:

What is the best strategy for the full growth and exceptional development of the plant?

Forget factors such as light, ventilation and temperatures (25 Celsius as standard) and focus on radically changing the substrate and irrigation. Having 2 options:
A) A substrate that retains a lot of moisture and drains well, with a high ambient humidity
B) An inert substrate and constant watering, literally every time the roots dry out

In an ideal world, what would be appropriate? I read this article in First Rays: General-Recommendations-for-Feeding-and-Watering-Orchids
I then mention that the best option is B

I want to raise sublime orchids, which method is the most appropriate. Of course this assumption does not apply to Phrags and Paphios that need constant water, like the photo above.

https://i.pinimg.com/1200x/31/69/fa/...182c58bf17.jpg

[Ray]

Nowhere in that article did I recommend letting the roots dry out and I did not necessarily recommend an inert medium.

What I said was "Select a potting medium and container that allows frequent watering without suffocating the roots, and water it frequently – the more, the better."

[estación seca]

The four genera you mentioned have different water/air/humidity/light requirements for ideal growth. You won't be able to grow all four together to perfection at 25C.

[Roberta]

Of those, note that Catasetums have a completely different growth pattern than the others. Catasetinae lose leaves in the fall, go dormant. During dormancy they need to NOT have any water or fertilizer. And in the spring, as new roots and new growth start, you need to resist the urge to water until new roots are about 10 cm long at least. When they get into rapid growth in the later spring, they need lots of water and fertilizer. Look through the Catasetum sub-forum, you'll find lots of cultural information.

Cattleyas, there are lots to choose from, and different species (and their hybrids) have different needs. Anguloas and Lycastes are different yet. They tend to need a rest period in the fall/winter, but not as severe as that for the Catasetinae.

So.... I think that you need to do a lot more research, with specific species (or hybrids) within the genera that you are interested in. You need to master the basics for each, and there lots of differences, within genera as well as between them. There is no single set of conditions that will work for this wide range of orchids.

[PuiPuiMolcar]

I have seen an oncidium with psuedobulb as big as big as my hand at norman orchid. You can check his channel for the video on oncidium to see how he does it.

[Roberta]

Originally Posted by PuiPuiMolcar

I have seen an oncidium with psuedobulb as big as big as my hand at norman orchid. You can check his channel for the video on oncidium to see how he does it.

Also, note which one... "Oncidium" is a big genus, and it has gotten bigger with reclassifications that include Odontoglossum and some other genera that used to be separate. Which also changed the intergeneric hybrids in the group. The human-made genus Maclellanara includes some hybrids with large pseudobulbs. Getting big pseudobulbs starts with genetics. You can't get a Chihuahua to grow to Great Dane size by feeding it more.

[Cach26]

Okey, I understand well all the edaphoclimatic requirements of all these species, their dormancies and growths etc. And yes, if it is possible to develop large seedlings very decent and that bloom at 25C (It is not ideal, but managing factors such as irrigation, ventilation and polyshade can. It is NOT impossible)

---------- Post added at 05:43 PM ---------- Previous post was at 05:37 PM ----------

Sorry for not expressing myself correctly, I read English, but I don't speak it I only use translator. In fact I want to ask this:

Orchids that are considered "voracious" in their growth stage (Let's focus only on Catasetum so as not to complicate) What does that orchid need if I want it to have optimal growth?

A substrate that retains a lot of moisture (with few risks)

Or a substrate that retains very little moisture, but with many frequent waterings

That's why the title
Moisture vs Irrigation

---------- Post added at 05:50 PM ---------- Previous post was at 05:43 PM ----------

"Getting big pseudobulbs starts with genetics. You can't get a Chihuahua to grow to Great Dane size by feeding it more."

Excellent answer and comparison, it really clears up many doubts

Ok, let me explain, I want to grow large plants XD, and I know that this requires good culture, as I explained, I already mastered the other factors, and I want to give that "fine touch" to irrigation and humidity

[PuiPuiMolcar]

Originally Posted by Roberta

Also, note which one... .

This is the one i was talking about, he said it was a sharry baby oncidium.

[Roberta]

For Catasetum (and related genera) I just add a "top dressing" of time-release fertilizer (in the spring) to supplement my normal (very light) fertilizing. I do the same for Cymbidiums. So not precise, just a little "boost". For the Catasetinae, I use sphagnum moss for most, since while growing I want to keep them wet. If I have a large one, I may use small bark since there's enough mass to hold moisture while allowing for air.
If you want to choose a robust, easy-to-grow Catasetum, consider Ctsm. expansum. It should not take very many years to get one to big, fat pseudobulbs, and it can bloom twice in a season.

[Ray]

I think you may be looking for a simple answer to a very complex question.

Point 1: In order for any plant to add one pound (454g) of mass, it must absorb and chemically process about 200 pounds (~91 kg) of water, but only 5 grams on NPK nutrition.

Add to that the fact that most plants lose as much as 95%-99% of the absorbed water to transpiration, and the mass of water to be absorbed must be on the order of 4000 pounds of more.

That's a LOT of water to be available, and it gets more complex when you consider that orchid roots' "reach" is very limited - there might be 200 grams of water held in the mix, but how much is actually absorbable?

Then there's the question about absorption dynamics - how fast can it draw the water in? Sure, the velamen absorbs almost instantly, but how long does it take - and how much of it - is absorbed by the plant?

Figure those things out and we'll all be grateful!

One last point - "humidity" is water vapor in the air. It may slow the loss of absorbed moisture, but it's contribution to the water within the plant is negligible. They need liquid water.