Rootless orchid with new leaf, repeated soft rot infection, what's going on?
 

I rescued 2 Phals a month ago, they were in one pot. One of them had only 2 small good roots. I put it into full water culture. Both of the roots died and it lost most of its leaves. But today I noticed a new leaf growing. Is it a good sign, or it's just using up its last bit of energy from the leaves it has lost? Why no roots are growing, just a leaf?

The other phal is recovering very nicely, it's not in water culture, just bareroot. I water it 1-2 times a day. The only problem is that its repeatedly getting soft rot on different parts, which I keep chopping off. The other orchid next to it in FWC seems to be unaffected by soft rot. Why does this disease keep coming back?

I have no idea. I find with Phals, it can take time to understand what they are doing. If the orchid is not rotting or suffering in any way, just give it time.

Thank you, I will just wait and see. I hope it will live!

Without roots, it could be using the last resources of energy and water.

I think it's necessary to have at least some sort of idea about what can happen to roots immersed in water that doesn't contain enough oxygen for the roots, and/or the plant not getting enough nutrients or chemical elements it needs to grow well.

If bacteria or pathogens are in the roots (and in the plant) or in the water, then attempts to save the plant earlier on could be to apply some treatments for battling bacteria, and maybe go back to classical ways of growing orchids ----- general growing media.

Good air circulation to the leaves as well as to the media and roots can cut down on issues.

I can understand water-lilies and lotus plants getting roots dunked in water 100% of the time, as they have adapted or evolved to live like that - they need that sort of thing.

For orchids, I'm thinking that unless we have some sort of water aeration machine and control whatever is in the water very well ----- the orchid can just take an unexpected (or even expected) downturn in health.

I am not well versed about "full water culture", but here's my take on the scenario you described:

By submerging the roots, you have likely suffocated them. Keeping the base of the plant submerged is not going to help, and can hurt.

As roots grow, they "tailor" themselves on a microscopic level to the environment they're in, so they can function optimally. Once they have grown, that tissue cannot change.

Those roots did not grow in water, so were - literally and figuratively - completely "out of their element" when you stuck them in water, so died. If you want the plant to survive, it must have new roots. I doesn't matter a bit how you want to grow it, but the roots must be right for those conditions.

As it is, the plant has no way to take up water (base immersion doesn't cut it), but can lose it through leaf transpiration. The challenge is keeping it from desiccating to death before new roots emerge.

You can certainly keep it in that glass container, but 1) lower the water level so there is no contact with the plant (becoming a humidity source only), and 2) invert a clear plastic bag over the plant and container, without sealing it, to simulate a greenhouse to trap the humidity. Keep it VERY warm and in deep shade, and in a few weeks you may see new roots emerge.

Once that happens, you can repot it or leave it in the vase. If they continue growing and enter the water, that's fine, as they will be optimal for that environment.

You can accelerate the root-growth process through use of a good stimulating formula.

Thank you. I dumped out most of the water and covered it with a plastic bag. Can it be completely in the dark? Like on a shelf in the kitchen where no light reaches.

Do you have any idea why is the other one getting sick? It's without media, growing beautifully, it has a new leaf an a new root. Yet it keeps getting soft rot.

No, not completely dark - it needs some light to generate sugars to fuel its chemical processes. Don't be too concerned about that part, just make sure it received NO direct sunlight.

That suggests the plant is infected with some sort of fungus or bacteria, and until you can cure that, you'll be slowly whittling away at it... You might want to read this.