I just went to a new 1000w hps and I have no idea how many plants to put under it and still be effective. I was thinking 10-12 but im not sure if that will be to many and the outer plants wouldnt get enough light. I the light is stationary and i will not be putting it on a track system.
Determining lumens for your grow area:
Determine the square footage of your area
(example in a 4 foot by 4 foot area, there is 16 square feet)
If you have a 1000 watt High Pressure Sodium, that produces (approx.)
107,000 lumens.
Divide this by 16 (your square footage) 107,000 / 16 = 6687 lumens per square foot.
So just divide the total amount of Lumens, by the total amount of Sq ft,
and thats your lumens per square foot.
Approximate light production:
Incandescents: 17 lumens/watt
Mercury vapor: 45-50 lumens/watt
Fluorescents: 60-70 lumens/watt
Metal halide: 90 lumens/watt
High pressure sodium: 107 lumens/watt
How much light is needed?
The minimum amount of light required by marijuana plants is around 3000 lumens per square foot.
However, it's not 100% accurate, since although you may have a 10,000 lumen light,
the amount of light that reaches the plant varies with the distance between
the light and plants, and reflectivity of the grow box.
The ideal amount is somewhere around 7000-10,000 lumens/sqft,
and as long as the plants do not burn, as much light can be used as you want.
(*note, the sun produces about 10,000 lumens/sqft, on a sunny summer day).
* A 250 watt fixture will supply enough light to cover
a 2.5 foot by 2.5 foot grow area. (6 plants or less)
* A 400 watt fixture will supply enough light to cover
a 4 foot by 4 foot grow area. (12 plants or less)
* A 600 watt fixture will supply enough light to cover
a 5 foot by 5 foot grow area. (18 plants or less)
* A 1000 watt fixture will supply enough light to cover
a 6.5 foot by 6.5 foot grow area. (30 plants or less)
