Backyard Aquaponics
A place to discuss aquaponics

I plan on having a 4ft long by 2ft wide grow bed. Question is, should i have one long 4 ft by 2ft grow light setup, or should I have two separate ones (either 4ft long by 1ft wide or 2ft long by 2ft wide) so that I can plant higher growing plants under one light and adjust it according to those while still allowing the smaller plants to have lighting closer to them. Any thoughts? Does this even belong in the hardware forum btw?

Well more flexibility is always better, and multi-point source is always better (leaves shaded from one source can be illuminated by the other). That said, I assume you're using fluorescents? illuminated tubes are already multi-point since the whole tube illuminates. If it were my 4X2 I'd probably just use a 4X2 T5 fixture with four to six bulbs.

Understand though that like all lights, intensity diminishes very quickly with distance so if you're planning on a bed of greens along with tall tomatoes/cukes/whatever, then you definitely want two different fixtures: having a light above a plant of any height will put the lights too far from a canopy crop like greens to be useful.

So long/short, it depends on your crop plans.