My habs were a little slow to germinate than the reapers and bhuts I planted -- eight days for the hab seeds vs. five days for the others. Bed temps for all was 85 degrees.
Habs are slower to grow than the others, too...they are healthy, but short and stout. Lighting for the habs is much, much better than what I'd used for the beginning stages of the others. From what I understand, it's usually a matter of either heat, light, nutrition or genetics.