Whats going wrong with my phals

[estación seca]

Do you have a shady porch? Phals are much happier outdoors in typical Midwestern summers than inside air-conditioned houses. They prefer warm to hot temperatures. Watch out for squirrels.

[Orchid Whisperer]

Ray could be right about cold and mesophyll collapse. What would be the coldest temperatures your plants have been exposed to in the last month or two?

I am in agreement with the others about getting your Phals out of the current mix and into a coarser medium, like orchid bark. No rice hulls, no worm castings. Bark pieces should be mostly dime to nickel diameter, or coarser, and it is helpful to have pieces of coarse inorganic drainage material (like styrofoam, or nickel-sized gravel) in the lower part of the pot.

You can get an appropriate orchid bark for about $5 per 8-quart bag at any home improvement center that has a gardening section (Lowes, Home Depot, Menards, Walmart, etc.) "Orchid mix" may be OK if you can't get straight orchid bark; use a colander to sift out fines.

[greenpassion]

I would think the simplest thing to do is get some Orchiata, medium chunk, as was mentioned earlier. What the others are saying is true-you just can't get around the fact that phals need a potting medium that allows free water passage, and air to the roots. Also, they don't get their nutritional needs met through what they're potted in, but from the water they're given. In nature they get what they need through the rain water and water that drips onto them from the above trees and plants. I mention that because using worm castings is not something your phals will benefit from.

[pychou77]

The leaves look dehydrated because the roots have been exposed to too much moisture for extended period of time. The condition is perfect for harmful microorganisms to grow, and they are having lunch on the roots.

Use a small pot and coarse potting mixture for shorter dry-wet watering cycle. You may need to remove rotten roots before repot them. If the roots are in really bad conditions, try setting up something like this:
Phalaenopsis Orchid with yellow/brown leaves

[Ray]

Originally Posted by pychou77

The leaves look dehydrated because the roots have been exposed to too much moisture for extended period of time. The condition is perfect for harmful microorganisms to grow, and they are having lunch on the roots.

I disagree.

Dissecting this comment backwards; microorganisms typically do not "take down" healthy tissue. If the conditions are such that the roots suffocate, or get too cold and then die, THEN the microorganisms will go to work on the necrotic tissue.

There is no such thing as "too much moisture", by itself. There are just too many well grown plants in Semi-hydro culture, full hydroponics, and with roots fully submerged in water culture for that to be true. Besides, many phalaenopsis (and other orchids) in nature experience months and months of saturation. If the moisture works poorly with the potting medium to cause suffocation, that is an issue.

As I stated earlier, the pattern of the damage to the leaves does not suggest general dehydration that would result from root damage. I such a case, the entire leaf starts to become sunken-in, and loses its turgidity.

[pychou77]

Originally Posted by Ray

I disagree.

Dissecting this comment backwards; microorganisms typically do not "take down" healthy tissue. If the conditions are such that the roots suffocate, or get too cold and then die, THEN the microorganisms will go to work on the necrotic tissue.

There is no such thing as "too much moisture", by itself. There are just too many well grown plants in Semi-hydro culture, full hydroponics, and with roots fully submerged in water culture for that to be true. Besides, many phalaenopsis (and other orchids) in nature experience months and months of saturation. If the moisture works poorly with the potting medium to cause suffocation, that is an issue.

As I stated earlier, the pattern of the damage to the leaves does not suggest general dehydration that would result from root damage. I such a case, the entire leaf starts to become sunken-in, and loses its turgidity.

Moisture does not kill orchids per se (e.g., in flask). However, some orchids (Phal for one) are very vulnerable to microorganisms that flourish "specifically" in extended wet conditions.

Most water culture methods, if not all, I believe, use inorganic materials, including water. For experiment, just add a few pieces of bark to your water culture or S/H and see what would happen.. .

[Ray]

Originally Posted by pychou77

Moisture does not kill orchids per se (e.g., in flask). However, some orchids (Phal for one) are very vulnerable to microorganisms that flourish "specifically" in extended wet conditions.

Most water culture methods, if not all, I believe, use inorganic materials, including water. For experiment, just add a few pieces of bark to your water culture or S/H and see what would happen.. .

It is quite common for bits of organic media to be stuck to the roots of plants when they are moved into the constantly-wet environment of a semi-hydroponic pot, and - yes - that material begins to rot in fairly short order. That, however, has no impact on the roots of the plant.

I think you're putting the cart before the horse, here. Those visible (ectomycorrhizal) fungi do not grow and then attack healthy tissue, but only begin to make themselves be known after there is a supply of already-dead organic matter upon which they can take advantage. In fact, as that happens, nutrients that are otherwise unavailable to the plant are released into the rhizosphere (although I'll admit that in a flower pot it amounts to zilch).

Microorganisms are very specific when it comes to what they'll take advantage of. Pathogens attack living matter, not dead tissue. Take those in the genus penicillium, for example - they definitely decompose organic matter, but kill pathogenic species, rather than destroying the host tissue they're growing in.

Orchiata bark is naturally "infected" with trichoderma and penicillium, and that works to the plants' advantage!

[pychou77]

Originally Posted by Ray

It is quite common for bits of organic media to be stuck to the roots of plants when they are moved into the constantly-wet environment of a semi-hydroponic pot, and - yes - that material begins to rot in fairly short order. That, however, has no impact on the roots of the plant.

I think you're putting the cart before the horse, here. Those visible (ectomycorrhizal) fungi do not grow and then attack healthy tissue, but only begin to make themselves be known after there is a supply of already-dead organic matter upon which they can take advantage. In fact, as that happens, nutrients that are otherwise unavailable to the plant are released into the rhizosphere (although I'll admit that in a flower pot it amounts to zilch).

Microorganisms are very specific when it comes to what they'll take advantage of. Pathogens attack living matter, not dead tissue. Take those in the genus penicillium, for example - they definitely decompose organic matter, but kill pathogenic species, rather than destroying the host tissue they're growing in.

Orchiata bark is naturally "infected" with trichoderma and penicillium, and that works to the plants' advantage!

Actually, I think we are getting closer to agreeing with each other, at least on one thing – microorganisms are very specific.

Different microorganisms flourish in different environments.

What I am saying is not to provide a breeding ground for microorganisms that are harmful to the orchid. Microorganisms flourish in an environment similar to the natural habitat of a particular orchid tend to be more beneficial to the orchid. They might even help to fend off those harmful microorganisms, as you suggested.