Rootless Phal putting out leaves instead or roots
 

I have a phal that had a bad mold issue, killed off most the roots, I remedied it and it remains with 1 tiny root, one knub, and a half alive half dead root.
I placed it in a soda bottle style terrarium with some water on the bottom, phal sits on rocks. Hoping for it to grow roots, since the roots left are barely half an inch..
I waited, and about 3 weeks later no new nubs starting whatsoever. A bottom leaf is yellowing, and peaking thru the top I noticed a baby leaf down in the crown. How is it going to sustain the new leaf plus the 4 it has now. All still healthy looking, but I am very nervous of them becoming floppy. Any advice? Why is it putting out a leaf instead of roots.

Phals really do not need a "lot" of roots, though it is better for them if they have more. I read this as a situation where your plant is getting larger and will start root growth. Each grows at "different" times, although many people will most likely debate this. Each action must be "turned on" by a cascade of hormones caused by signals it receives from the environment (angle of the sun, humidity per time of year). Each part of the light spectrum is used differently. Blue light is specifically used by plants for vegetative growth. Using the blue spectrum to help plants grow stronger is a good idea. Cool LED lights in blue are helpful, if you can go that route. Also keep it at the highest light that it can take. If phals are 800 to 1500 fc, then try to go the entire 1500.

Remember that light is food to a plant. They use it differently than humans.

Phals can take up a lot of water from a small root system. They can support an amazing number of leaves with a small root system, if properly watered. That means water on the roots, not just humidity around the plant.

The developing leaf is taking water from the oldest leaf. As the new leaf keeps growing, it will do this to the oldest leaves, one by one, unless you start watering the roots.

Take the plant out of the terrarium. Notice the roots are tan, white or silvery. Dip them in water for a few minutes. Notice they turn dark green. The velamen coating of the roots is full of water. Return the plant to the terrarium.

As soon as the roots have turned from dark green back to tan, white or silvery, you can repeat the dunking.

A kelp product like KelpMax can help stimulate more roots.

When the plant is making more roots, you can repot is.

Mold seldom kills orchid roots. It is more likely they were already dead, and fuzzy mold grew on the dead roots. Most dead Phal roots are killed by overwatering. Here is a good thread to read on caring for Phals:
The Phal abuse ends here.

Thank you very much, this was helpful =)

As ES says, new leaves can take water from old ones to keep going until roots grow. The photosynthesis that is performed by the leaves is the source of energy (carbs) that the plant needs to stay alive and grow (so don't worry so much about the roots "supporting" leaves... the leaves also support the roots by feeding them) It may be slow going at first but with new roots developing, things are going in the right direction)