Yeah, they're pretty well all clear, some (I'm growing a first BD right now but it's still in veg) strains frost up earlier than others. Not a bad thing but you still have 4 weeks or so, those are all clear trichs and the buds have developed but they're nowhere near mature. Here's a Jack The Ripper and Pure Power Plant at 31 days, the JTR is frosting up well but all clear frost, buds are well developed but they now have to ripen/fatten up, another 3-4 weeks to go...