Halogen light caused that. And dare I assume that if you are using a halogen light, you probably don't have your lighting setup ironed out yet? Low leaves will doe off if the light is incorrect.
Please read up a bit on growroom setup- link in my sig is written out of order but very informative.

Just FYI- Without pics and filling out the troubleshooting sticky at the top of this forum section, NO ONE can tell you what is wrong with a plant. We are not mind-readers. You have to give more info than 'some leaves are wilting'. That could be just about ANYTHING.