how many plants can i grow in a 3x3x4.5 cabinet ?

ok i been growing for over a year good and bad turn outs. lately i been tryin to grow 6 plants and from clone to full vegitative state they looked fantastic ! but about 2 weeks into the flowering stage every single plant is tying ! leaves stems everything is wilting over. i can't figure out what could have caused this unless that's just way too many plants in such a small room
 
Top