What light at what stage of growing marijuana

A question from a fellow grower:

i was just wondering if you could shed some light on what wattage of lights you would recommend throughout each of the growing stages???

No matter the light, if you can find the exact specs for its lumens/FLUX per square foot (or the equivalent PAR for red/blue only LEDs) you can use this as a loose guide:

Seedlings and clones require about 400-1000 lumens per square foot.

Vegetative growth requires about a minimum of 2,000 to 3,000 lumens per square foot.

Flowering requires about 5,000 to 10,000 lumens per square foot, ideally, and can take possibly much more.

10,000 lumens is supposed to be about the average power of the sun at sea level on a lightly cloudy/hazy day at high noon, or something like that, lol.

It’s not idea, but you can make do with 2000 lumens for an entire grow if necessary.

I like to use a 400 watt Metal Halide for Veg, and a 1000 watt HPS Hortilux for Flower; Along with a 250 watt HPS as a side light.
For seed starting or clones, fluorescent are great for the versatility, but you can pop seeds under fluoro tubes, cfls, and up to a 400 watt Metal Halide. Good Luck :smiley: