Looks like they got a bag of BM7 and "cut it" with a bag of the cheaper Jemasco potting soil they keep out front haha. I'll check it out next time I'm there. As long as it's not the old potting mix from their greenhouses I'll probably get some.
not really a trick but making sure your seed stock isn't old goes a long way. I've tried soaking seeds but I'm not sure it helped that much with germination rate. I might suggest an on and off heat cycle to replicate day and night temps but that may just decrease gemination time.