My closet is 22.5" x 22.5"... I use a 400w hps, 2 plants in Scrog (2nd link in my sig). Yielded a QP in 3+ months (5 weeks veg, 8-9 weeks flower)

With a 400w you will need a cooltube and inline fan. Mine was 129cfm, but now I'm thinking about getting a bigger/better one.

4 plants might be a little tight... but as long as the containers fit, you can always LST or Scrog to make the plants fit better.

Good luck and keep us updated :jointsmile: