maryjane are very vulnerable, so you have to take really really good care of em or they will stress the fuck out. It should already show its sex by now. Female plants usually have pistols shooting out while male plants have nut sacks hanging between the main branch and the smaller branches that grows out. 12/12 in 3 weeks i always have buds the size of popcorns already. It looks to me that you are using some cheap dirt that is compact as fuck.... I've worked with dirt and hydro, so to me it may be over watering.... I water my plants ONLY when it starts drying on the surface of the dirt... Next time if you wanna go cheap, then go with miracle grow(green bag). Miracle grow has all the nutrients in it already that will last for up to 6 months.... When i water them, i usaully only water them with PH water with no nutes at all until the last month of flowring because i always notice by that time, its in need of nutes... I've grown straight whole cycle with miracle grow before without nutes and it also turns out to be pretty good in yields too.....
