Well, it is not that they should, but if you have 45%RH around, then some moisting, spraying or covering would help.
But it is only a guess, you had better describe your situation more precisely and some photos, of course.
Because there is something wrong, Think Different sprouts in 2-3 days and then they need 2 more days to get out of soil. Mostly that ones that were a little bit late come up in line with others in couple of days.