how much space do people leave between there plants in bud?

hi all, i have a question regarding getting the best use of space out of my growrooms, i am concerned that i may be looking at putting to many plants into such a small area, my bud room run off tray is around 60cm x 120cm which i intend to feed via a dripper systerm. any advice regarding this matter would be greatfully recieved as i just want to get the best out of my girls. some people have said it would be possible to get around 16 to 18 plants on here but i feel it may be to many.
 
Top