HOW MANY PLANTS CAN I GROW IN A 2'x2' AREA?

Im gonna buy 2 sour kush and 2 northern lights x big bud feminized seeds so i was wondering how many i can grow in that amount of space. I want to vegg for about 3 or 4 weeks before i start flowering so there gonna be kinda big. So how many can i fit and is it ok if their kinda packed in or do they need alot of space? Ohh and im using 150w hps with 4 23w cfl's. Thanks in advance

150 hps is good for like 1 maybe 2 plants. I would get a 250hps for 2x2, make sure ventilation is good.

Most def need the 250w.
1 big ass plant that's trained some sort of way.
2 medium sized plants.
4 good sized plants.
With the limited head room, I would look into SCROG or LST.