No its not! Im trickky

Seriously tho 5feet above the plants? or 5 feet of the floor???

Just pop your hand on top of the plants and lower your light till it starts to feel warm (pleasantly warm not hot)

If your worried that the plants at the perimeter of your garden wont get as much light then swap them round every couple of days. But if some are smaller then I would keep them under the light till they catch up a bit rather than on the perimeter of your garden.

S'up to you tho.