I would expect your palms and ferns to fall into the "low light" category, needing around 200 foot-candles. You might want to check the light requirements for the exact species you will be growing.

So you will need something like 6,000-8,000 lumens. You can get that from a couple of high output fluorescents (maybe four, depending on the exact spec and light levels you need) if you use good reflectors or a suitable white enclosure. HID lamps aren't worth the trouble and expense for this level of light, only consider them if you need more than twice that amount of light.

I don't like the sound of the UV fluoros. Lizard lights? Aquarium lights? Not suitable.