Lighting — For 90x60

A 90x60 is a rectangle, and that is precisely what makes this size awkward. Almost every grow light is designed to fill a square, so here you are looking for a compromise between light that reaches along the length and light you do not waste against the side walls.

What this size holds

The Lumatek ATS 200W Pro is a passively cooled fixture with no fan, which makes it silent and leaves nothing that can seize. The Spectrabox UFO 200W is compact and penetrates more deeply from a single point. Both sit around 200 watts, which is generous for this floor area.

Square light in a rectangular space

Both of these fixtures throw a more or less square pool. On a 90x60 that means either matching the short side and losing a little at the ends, or matching the length and losing light against the long walls. That is not a fault in the lamp but a consequence of the tent shape. Hang it centrally and use the ends for something other than a fully grown plant and it matters less in practice than it sounds.

What would help and is not here

For a rectangle a bar fixture is the better shape, because it spreads light along the length rather than in a circle. There are none in this size, but the separate bars under supplemental lighting can hang alongside a main lamp to light the ends.

Or look at a square size

If the tent shape is still open to you, a square space of comparable area is simpler to light. At 80x80 the choice is wider and the shape of the pool fits better.

Frequently asked questions

Is 200 watts not too much for this size?
On the generous side, and that is no problem here: you hang it higher or dim it. Generous and turned down runs quieter and cooler than tight at full power.

What does passively cooled mean?
That there is no fan in the fixture. It saves noise and there is no part to seize, but the fixture does need to shed its heat into the air around it.

Can I hang two smaller lamps side by side?
On a rectangle that often works better than one large one, because you spread the pools along the length. Do add the total wattage together.