Twenty percent of the light emitted has
been deducted from the total to correct for
reflector inefficiency and light which never
reaches the garden. Light is never
distributed evenly so some parts of the
garden will get more light than others.
Garden # of # Of Lumens Per Square Foot
Size Sq. Feet 400 MH 1000 MH HPS 400 1000 HPS
3’ x 3’ 9 3,500 11,100 4,450 12,450
4’ x 4’ 16 2,000 6,250 2,500 7,000
5’ x 5’ 25 1,300 4,000 2,000 4,500
6’ x 6’ 36 900 2,800 900 3,100
7’ x 7’ 49 650 2,050 650 2,300
8’ x 8’ 64 500 1,560 390 1,750
9’ x 9’ 81 400 1,250 500 1,400
10’ x
10’^100300 1,000^400 1,100
LIGHTS AND REFLECTORS
Sunlight comes from a distant source,
so that the light rays hitting a small portion
of planet Earth (say a garden 12 feet wide)
are virtually parallel. Their intensity does
not diminish over the length of a plant 6 feet
tall.
Light emitted from tubes and lamps
travels in all directions. As the distance
from the lamp increases, the intensity of the
light decreases. It is not that any light is
lost, just that the same amount of light is
spread over larger area.
HID lamps and reflectors come in two