LED hieght..

Odog913

Odog913

Member
Hey crew.. very new here and just looking to get some input to start from.. I have 3 plants from 10 to 14 inches tall.. and a mars 2 700w light.. pulling about 345w from wall.. right now it's set to about 24 inches from top of plants.. what's first things I should check for.. I've herd about enough distance to "BLEND" the light together but how much room.. thanks alot for the tips
 
Not sure what the optimal distance is for that light but I would just watch the length between internodes on the plants and adjust accordingly. If it's too high they will be stretchier. Find a distance that fits the plant structure you want. You'll be able to figure it out quick. Good luck.
 
Im growing under two viperspectra 300s and my plants will burn anytime they're below 18"
 

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I also put my COBS about 6-8 inches from canopy without any signs of stress or burn during flowering only though.
When I was using hps lights, I'd go as close as I can too. Sometimes the bulb was about 10 inches. Depending on wether the bud directly beneath it was showing stress, I'd move it up or down accordingly.
Must be strain dependant, or some of us are using special nutrients.:roll:
 
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goofy81 said:
I also put my COBS about 6-8 inches from canopy without any signs of stress or burn during flowering only though.
When I was using hps lights, I'd go as close as I can too. Sometimes the bulb was about 10 inches. Depending on wether the bud directly beneath it was showing stress, I'd move it up or down accordingly.
Must be strain dependant, or some of us are using special nutrients.:roll:
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I wanna see more of your COB LED array.
 
I took my Lux meter to a friends grow to get some measurements. Both his SE and DE HPS at the canopy was 200,000 lux. I run my COB's @ 250w each and 200,000 lux is about 16" for me. That is my new target for me. Another friend has the same light as close as 14" and they are loving it.
 
nevergoodenuf said:
I took my Lux meter to a friends grow to get some measurements. Both his SE and DE HPS at the canopy was 200,000 lux. I run my COB's @ 250w each and 200,000 lux is about 16" for me. That is my new target for me. Another friend has the same light as close as 14" and they are loving it.
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If you look at ppf to lux conversion charts, 1000 ppf converts to about 82,000 lux for hps. 200,000 lux (under hps) would be 2440 ppf. COBs, having a wider spectrum, would measure much higher, probably similar to cmh - 200,000 lux of cmh would be 3000-3500 ppf (depending on cri & color temperature).

Are you sure your meter is measuring properly? Your numbers seem 2-3 times higher than normal.
 
DrBlaze said:
If you look at ppf to lux conversion charts, 1000 ppf converts to about 82,000 lux for hps. 200,000 lux (under hps) would be 2440 ppf. COBs, having a wider spectrum, would measure much higher, probably similar to cmh - 200,000 lux of cmh would be 3000-3500 ppf (depending on cri & color temperature).

Are you sure your meter is measuring properly? Your numbers seem 2-3 times higher than normal.
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Also curious to know what meter it is.
I try run 400,000-500,000 lux at my canopy on my el'ebay lux meter. With my hps, I'd try get 300-400,000 lux before it got too hot.
The summer sun shows an error on my meter because it's way too bright!
I do wish I had a proper ppfd meter though. They are just way too expensive
 
DrBlaze said:
If you look at ppf to lux conversion charts, 1000 ppf converts to about 82,000 lux for hps. 200,000 lux (under hps) would be 2440 ppf. COBs, having a wider spectrum, would measure much higher, probably similar to cmh - 200,000 lux of cmh would be 3000-3500 ppf (depending on cri & color temperature).

Are you sure your meter is measuring properly? Your numbers seem 2-3 times higher than normal.
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My COBs put out about 12k-13k lumens and 900-1000 PPFD. I don't think you are measuring it right. PAR photon density and lumen output are measurements independent of each other.

Also, you mean PPFD. PPF would be a smaller number.
 
goofy81 said:
Also curious to know what meter it is.
I try run 400,000-500,000 lux at my canopy on my el'ebay lux meter. With my hps, I'd try get 300-400,000 lux before it got too hot.
The summer sun shows an error on my meter because it's way too bright!
I do wish I had a proper ppfd meter though. They are just way too expensive
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There are ones that are quite cheap that have a relatively small difference to the super expensive ones.



 

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BM9AGS said:
If it's easy to take off the lenses you'd get more light to the plants and could grow taller plants.

I'm gonna do it with my Zelions
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@BM9AGS - that is a great idea - very interested to see what that does. When we were working with Osram on that fixture I was not pleased that they decided to use such a tight angle secondary lens (52°) given that the diodes come natively with an 80° lens already.
 
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