Next time you want to get stubborn seeds to crack place them in the freezer over night. I have gotten quite a few stubborn seeds to crack in the past this way. Also I like to soak my seeds for 24 hrs in water and a splash of h2o2 it helps to soften the seed casing. And last trick is to actually crack the seed just barely with tweezers or some type of pliers would work you must be very careful and that’s a last resort but it works. When you manually crack them you want to put pressure on the seems of the seed casing not on the round smooth part that will just smash them.I am having a rough time getting the two Sweet Tooth seeds to pop. The other Amnesia Fast seeds popped two days ago and were pot in soil. The seeds were done the exact same way but the ST seeds look like Duds. I will grab two more and try them. If they don't pop in two days I will look and see what else I can run that will finish in time. I have a couple Autos and I have Bubbas Island Kush that says 7 weeks so I may try a couple of those