Fertilizer is very low on a priority list for meeting an orchid's needs. Echoing some of the prior comments, an orchid won't use fertilizer unless it is actively growing and has healthy roots. There is no harm in waiting.
A possible harm in providing fertilizer too soon: if there is any root damage following the re-pot, added nitrogen and other nutrients could potentially fuel growth in bacteria and fungi (both require nutrients to grow).
I don't want to stress this plant any more than what she is presently.
From what I have read, taking it all with a grain of salt, it seems Phals in general "bounce back" faster (relativity speaking) than other species of orchid. I realize that its actually a case by case sort of thing since there are so many factors that have to be consider.
The Phal is now potted in a clay pot rather than a clear plastic (me and plastic pots are not a good combo no matter what species of plant) so seeing new roots might be a challenge. That being said I was thinking it would at least 8 to 10 weeks at the earliest to adding orchid food. That would put it around early to mid March when (in theory) the weather will begin warm here in the Northern Midwest and daylight will really start to become stronger.