Northern Lights: Is a 1 x 1.5 ft x 3.5 ft tall big enough?

I started putting together my grow box. It's 1 foot wide, 1.5 feet long and 3.5 feet tall.

I plan on growing 2 Northern Lights plants in there.

Is this big enough?

no. taller, you need a light and space between light and plants and pots.
and deeper at least 1.5x1.5x5..5

Will work, you don't put a lot of info out there so here is my best guess. If you are going to soil grow a 3 gallon pot is about 10 inches, if you plan on HID that's another foot for the fixture and hangers, a foot or so between the light and the plants and there is your 3.5 feet. I have a 2x2x4 with a t5 that is much thiner than an HID and doesn't require the large space between the plants and the right. Two in there is very tight, they are right on top of each other, right now I have one 14 in Bubblegum in there in a hempy bucket and the fan leaves almost go wall to wall. Your results may vary? Good luck.