Light height in commercial grows

I've noticed in pictures of larger commercial grows in Colorado, etc that their lights aren't hung within 12"-24" like most of us home growers. They appear to be using the same formula of 1,000w per 4'x4' area. So... what gives? They appear to be getting similar harvests as the rest of us.

Anyone care to pontificate?

If you use a Gavita 1000/DE, they need to be a minimum of 36 inches, and cover around a 6 x 5 area. They put out huge amounts of IR and are made to overlap each other.

Gavita are made for use in multiple light gardens, and when used in this way blast the area with more than enough light with the light further away from the canopy.

I wasnt a believer until I got a couple of the Gavitas. I experimented. I had the lights 40 inches from the canopy for a week, and all was well. I dropped the light down to 30 inches, and in 2 days they showed light stress, so they were raised back up to 40 inches, and then down to 38. Id shoot for 36-40.

I can get a 1000w Hortilux HPS 18 inches from the top.

In lower ceiling grows, for me. The HPS Hortilux is the way to go, unless you have 9-10 foot ceilings.

A 1000w Hortilux is good for 16sq/ft at 2 feet

At 20 inches the Hortilux is probably putting out as many Umol as the Gavita at 40.

Initially the Gavita is 2100umol

Hortilux is in the 1600's. At least 20% less, and Gavita keeps 90%-95% of its power for a year vs most all single ended bulbs lose 15% within 30 days.

I change flowering HPS every 90 days.

Veg on 24 hours 1000w, every 60 days.

1000w Gavita is good for 6 x 5. 32 sq/ft

Its easy to see you can get more production from the Gavita, as it covers almost double the area.

it's not just the Gavitas, it's nearly all DE (double ended) high intensity discharge (h.i.d.) lights, they're more intense than single ended bulbs, and are designed for commercial use.
what ever the footprint they're using, it's been time tested and adjusted to give the most efficient coverage for the crop they're growing.

Roger A. Shrubber said:

it's not just the Gavitas, it's nearly all DE (double ended) high intensity discharge (h.i.d.) lights, they're more intense than single ended bulbs, and are designed for commercial use.
what ever the footprint they're using, it's been time tested and adjusted to give the most efficient coverage for the crop they're growing.

Click to expand...

Even single ended bulbs with high quality digital ballasts give about a 30% increase in light. Then add the increase from going to de.

Because of the way the inverse square proportion law works you can raise these more efficient lights higher and they'll not just cover more area but they'll spread the horribly uneven spread of the gavita type reflectors out better and eliminate shadows with the overlap. Another advantage is that you can take advantage of stratification. With the lights up higher the heat is never anywhere near the plants.