"even if I had to make you eat some words to do it."
For what it's worth you didn't make me eat shit! You should be so lucky.
Dude, this is my last post dealing with you, as you seem very closed minded.
The chart that you find "amusing" was designed by a world renown grower(CaliGrower), and a contributor at cannabis culture magazine. In an attempt to be totally fair with you, and unbiased, I sent the question over to her, to get an unbiased opinion(s) on the lighting setup. While I did make some mistakes in my calculations, my conclusion was still correct.
This is how I posed the question to her, and her response to it:
Hey, if price is not a factor, what would be better, two 430 watt hps lights in a room or one 1000 watt light?
I looked at caligrowers light chart for reference and came up with this, tell me if it makes sense to you too?
the "usual safe distance" for a 400 watt is about 12"
the "usual safe distance" for a 1000 watt is about 24"
Based on that I figured that
a 1000 watt light emits 11k lumens at about 24 inches
a 400 watt emits almost 17k lumens at one foot
17k x 2 400 watt lights= 34000 lumens
Meaning the two 430 watt lights are a much better investment than the 1000 watt light.
Unless some of my assumptions are flawed?
Am I missing the boat, on luminous intensity?
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I’d say you weren’t reading that quite right.
One little thing first. Illuminance is lumens/area. When the area is square feet, you’re dealing with Foot-Candles. So, you’re correct for lumens/ft.² or Foot-Candles for your numbers above, not lumens.
The way I have the color-coding for safe distance on the chart is to keep the tops of the plants from receiving more than 70,000 Foot-Candles. Some like to have the tops that close and some like to back off a bit more. 70,000 is a bit aggressive for my taste and will usually discolor plant tops and destroy potency at the very top of the plants. With an air-cooled hood or at least a fan blowing directly on the bulb you could very safely have the tops receiving 30,000 Foot-Candles. I usually have a 1,000 watt light about 14” from the plant tops and a 400 about 8” from the plant tops. In both cases, you’re getting about 35,000 Foot-Candles at the top of the plants. The 1,000 watt light is putting out more lumens and the tops of the plants are a bit farther away from the bulb, so the 1,000 will penetrate farther. If you put the tops as suggested, 14” from the top of a plant under a 400 would be 22” away from the light and would be receiving 4,735 Foot-Candles of light, and 14” from the top of a plant under the 1,000 would be 28” away from the light and would be receiving 8,185 Foot-Candles. So, you can see you’ll be getting 72% more illuminance 14” from the top of the plants under the 1,000 watt light. (See Note Below). This would tend to make you want to run out and grab the 1,000, but there’s a bit more to it. The light won’t go through a leaf or any solid object. So, 2 feet down a plant the light is shaded heavily by leaves. Light penetration is decreased by more than the square of the distance due to the leaves being in the way. Now, this would tend to make you want to run out and get the 400’s. LOL! Going back the other direction, the 1,000 is more efficient than the 400 watt bulb and is also 200 more watts. Now, you’re also talking about 430’s, which would deliver 60 more watts total, and would only be 140 watts shy of the 1,000. I like to spread the light out more and try to keep the plants more compact. This way you also don’t have as much canopy to penetrate and you can really grow a greater number of shorter plants. If it were my choice, I’d go with the two 430’s. LOL! We came to the same conclusion in a bit of a different manner.
I actually like the 600 watt light due to the fact that it is more efficient than either the 400 or the 1,000 and gives the best of both worlds for spreading light and giving good penetration.
Note: The above might seem confusing when talking about 14” from the top of the plants, but I’m talking about the distance from the light as being 8” + 14” = 22” for the 400 and 14” + 14” = 28” for the 1,000.
Another contributor over at CC added this:
Multiple lights will always cover a given area better than a single light....and possibly save you some electricity dollars.
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I am not sure if you'll be able to digest this info correctly or not, but there you have it!
Peace
PS, if you know me, or read any of my posts, you would know that my wishing you "peace" was anything but "non-genuine"...it was quite the oppisite.
)
