Match Watts to Canopy and Variety

Watt targets by plant type

Sativa: about 66 W per sq ft, or 700 W per sq m.

Sativa-indica hybrid: best near 60 W per sq ft (640 W per sq m), and still solid near 50 W per sq ft (535 W per sq m).

Indica: grows well at 40 to 45 W per sq ft (425 to 480 W per sq m).

Tighter indica buds: more watts than that baseline can pack flowers harder.

Empty floor: watts on bare pot or aisle do not count toward these targets.

A 25 sq ft (2.3 sq m) example

Legal note

some regions cap indoor canopy near this size; check your own rules

Same area, many shapes

a square rectangle or circle can all work if the light covers the plants

Tradeoffs

each shape changes how you hang lamps and walk the room

All can produce

the text treats these layouts as productive if watts match the variety

How to use the numbers

Measure canopy

use the lit plant area, not the whole room

Pick variety first

a lanky sativa in a dim indica room will stretch and underperform

Do not overlight a cool, low-CO2 box

unused watts become heat

Scale lamps

several smaller lamps can hit the same watts per foot as one large one

Planning check

Hybrid room

50 to 60 W per sq ft is a practical indoor target

Indica room

you can run leaner watts if heat is a problem

Sativa room

budget more power or a smaller footprint

Next step

once watts per foot are set, pick a floor shape that the lamps can cover evenly