You are seeing the plasticity of the mottled leaved Phals at work. This kind of plasticity is their adaptive mechanism. The brighter the light the smaller the leaves are in order to reduce the surface area of the leaves because they're getting plenty of light. If you drop the light levels, the leaves will progressively get larger in order to increase the surface area of the leaves so that it may be able to obtain as much sun as it can.
Same goes for watering. If you water less, the newer leaves will become smaller than the original ones. Increase the amount of water they receive, and the leaves will get as large or larger than the original leaves.
Last edited by King_of_orchid_growing:); 07-02-2011 at 03:42 AM..