you really dont need alot of space depend how long you veg for though but have even seen shelves used if space is an issue and you only veg for a few weeks with 4 ft flouros over them it takes up very little space, using small pots you can fit alot of plants in not a whole lot of space would estimate about 4 plants per sq ft if your only veg for a 3-4 weeks in a pot just large enough to carry them through the veg cycle.