Can someone describe the best way to re-pot this species?

Right now I have 5 nice plants sharing a wide, yet not very deep, terra cotta pot. The pot is about 15 inches in diameter and 5 inches deep. The plants themselves are about 2 years old and about 2 feet tall.

Can I leave the plants as they are or should I put them in a deeper pot?

I have them under a 400 watt HPS and a 400 watt Metal Halide plant light.

Thanks for any information you can share!

Sincerely, Eric

I have had my eye on this ginger for a little while-do you like it? Has it bloomed for you yet? Where do you put it in the summer-full sun or some shade?