2 x 4 x 5 tent

This is my first indoor grow and the plants are really filling out my 2 x 4 x 5 high tent. Two of my plants are 12 inches high and two are about 18 inches from the top of the pots, the pots are 12 inches high. One pot has two plants in it. They are in the 8th week from seed & I switched to...