HELP:Builing a grow box!

ok so i want to build a grow box to keep in my room mabie like 2-3ft x 4-5ft and 5-6ft high. im thnkin two plants at a time from clone straight into flower. is 400w ok? any help would help thanks!

400W is fine provided you have passive intake holes at the bottom of your growbox. Also you need a scrubber mounted at the top with a fan to exhaust hot air. I have a growbox that is 32" deep 4' wide and 6' tall with (3) 2 1/2 intake holes at the bottom. I also have a 2600 can fan scrubber to exhaust hot air. I run 4-6 plants in 3 gallon pots 400W for veg and 600W hps for flower. Temps stay under 86 inn summer months with the 600. Just to give you an idea as you will be working with a similiar space. Look up my username, there are two post, its getting crowded in here and nirvana grow box has some pics of my setup. Good Luck BigJon626

Check out the box in my signature. It was really easy to build, and you could use a 400W easily if you used an air cooled reflector, and externally mounted the ballast.