three weeks flowering

try a good sized trash can place it over it for 12 hours id put a fan in theyre if u did that personally, ur plants need oxygen

looks male to me

actually your plants need co2 not oxygen haha! how old is the plant? and try 10 hours of light 14 hours of darkness. It looks indica dominant so it could help if were the reason.

they only breathe co2 in and oxygen out during the day during the night its vice versa they breathe oxygen in and co2 out thats why right when ur lights turn on you should leave ur room closed for like half an hour so they can breathe the co2 they've been producin all night