wordwiz

Richard,

I ave read what you have posted. Here are the posts:

Forget LED's for crops, although they are great for indoor tropical plants that enjoy low light in their natural habitat.
In the long run, the T5 High-Output Plant light systems are more cost effective, plus they give out a better quality light for crops and full-sun plants in general.

HPS plant-light bulbs are manufactured to be a supplement to daylight in translucent outdoor greenhouses in northern latitudes -- not a stand-alone source for indoors. For example: http://www.search.philips.com/search...oad/p-5828.pdf

The vast majority of HPS bulbs sold by manufacturers are used as lighting supplements. My clients -- who buy lights by the truckload, prefer the T5 HO full spectrum. It is also true that many distributors are making a nice sum of cash selling HPS bulbs to indoor growers. Its a small dent in the big picture.

I'm not selling any lights. I just do the physics as part of my consulting service.

When I evaluate plant bulbs, there are 3 manufacturers' graphs I value:
1. Output power spectrum. This is a graph of Watts or typically log(Watts) vs. nanometers. I ignore graphs that do not have units in the vertical range and do not extend through the infrared.
2. Output power spectral density. This is variance of power vs. nanometers. It shows you deviations in output under operating conditions.
3. Total power vs. operational time. This shows you when and how the output decays.
(The rest of the post truncated)

The greenhouses are all about 1 acre in size. One of them is dedicated to bananas. From fall through spring, the light through the roof is supplemented with full-spectrum plant bulbs for a total effect of 13 hours daylight at a rate of 1200 Watts per plant (at times, some of this is coming from the sun).

In terms of energy requirements to have a solitary dwarf Cavendish produce a meaningful crop, you'll need 800W output full plant spectrum for 9 hours per day provided the ambient air temperature is in the 75F to 85F range and the plant is receiving 2-3 lbs of something like 15-5-22 + minors & micronutrients per year.

For more standard size bananas, we use 2kW output per plant, of which about 1.2kW is incident upon the plant. The bulbs are 1 meter distance from the foliage. During the summer months, the sun provides about 1/2 of this but during the winter only about 100W to 200W. The nutrients are the same as below but the levels are at 5-lbs per plant per year.

(Taken from a post)
Fruiting banana cultivars do not occur in the wild.

These clients are in Riverside and San Bernardino counties (CA). They are growing dwarf varieties for local asian markets. My understanding is that the 1st two hands per bunch covers the production cost and the remainder is profit.

The relationship is non-linear and has more to do with fruit production than leaf growth. There are accrued energy levels to be obtained over time for maturation, etc.

No where do you state that you have any experience growing bananas, only "what you advise clients" which is using far more energy than necessary - IMO. I made a really simple proposal - we both grow a Dwarf Cavendish, me using a 125 watt LED panel, you using a 2,000 watt HID system that you posted you use. Then we compare the output.

If you get 16 times as much output as me, I'll concede.

Are you willing to put up?

Mike