Just ordered some BlackJack myself right before they sold out,(still waiting on them)...Supposedly this strain is done indoors between 61 and 65 days...Might be a little less,might be a little more...Six plants from seed are not going to be exactly alike...Best for you to get a scope and don't start weighing your buds before you even harvest,lol...I'm not familiar with your nutes,but if they're not organic,I'd start flushing soon if you think the grows about done...:stoned:

Sorry man,gotta edit...IF YOUR AT 4TH WEEK FLOWERED WITH BLACKJACK YOU'RE NOT DONE!!!