Help with how to judge LED light distance using a lux meter

U

Uzzi

Well-Known Member
G'day all

I was just looking for some assistance judging the optimal height of my LED lights above my plants?

I know that I could just keep lowering my lights every couple of days until I see burn then back them off. However, I have a lux meter and would like to know if I can go straight to the sweet spot? Maybe not as I can't seem to find this info anywhere for LED lighting.

A link to some reputable information would be greatly appreciated!

Thanks in advance!
Uzzi
 
U

Uzzi

Well-Known Member
Hmm what a lightning speed thread haha

To be a little more clear... I understand that with LED, distance is not judged by temperature as HPS and HID are. Jorge Cervantes specifies an amount of Lux that is appropriate for each stage of a plants life cycle. However, he does not include LED in his book so I am not sure if these guidelines are relevant. Some help would be appreciated....please
 
U

Uzzi

Well-Known Member
Thank you very much and great video (about to check ebay for a Kind LED light haha), but it doesn't indicate how to determine the ideal height of your LED light. The lights I have may be crap or even superior to other lights but I want to be able to determine the ideal height. I would imagine this would change with the age of the lights aswell. I also don't want to rely on manufacturer specifications. Thanks very much for taking the time though. Cheers!
 
justugh

justugh

Well-Known Member
Uzzi said:
Thank you very much and great video (about to check ebay for a Kind LED light haha), but it doesn't indicate how to determine the ideal height of your LED light. The lights I have may be crap or even superior to other lights but I want to be able to determine the ideal height. I would imagine this would change with the age of the lights aswell. I also don't want to rely on manufacturer specifications. Thanks very much for taking the time though. Cheers!
Click to expand...
to get your reading u set the lights at lvls

1 foot 2 foot 3 foot 4 foot 5 foot .......each one of those will have a different par ...the rating will go down as it goes higher from the floor
here is a reading from my lights
http://www.ledzeal.com/p44.html
midway down the page they will show u the par rating for the light at 1 meter and 2 meters
 
nomofatum

nomofatum

Well-Known Member
Par is the more perfect measure, but lux should be very close. Both measures are stongly related especially when the light color is isn't changing. Lux target will change slightly depending on your lighting color (slightly higher reading expected/desired if your lighting has more blue end spectrum.)

How much is a decent Par meter? A decent lux meter can be had for $20-30. A 95% accurate measure should be good enough when the alternative is to go off someone else's readings or buy a much more expensive meter. I would make lux work (it's close enough) or just go with trial and error. Unfortunately you may have to be the guinea pig and do trial and error while taking note of your measures.





I would compare your readings to these charts and guestimate with your trial and error.

I would note that I think these charts show a bit high for top end of optimal, I wish they put another color at the 8,000+ line for CO2 supplementation light levels.
 
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U

Uzzi

Well-Known Member
justugh said:
to get your reading u set the lights at lvls

midway down the page they will show u the par rating for the light at 1 meter and 2 meters
Click to expand...

nomofatum said:
Par is the more perfect measure, but lux should be very close. Both measures are stongly related especially when the light color is isn't changing. Lux target will change slightly depending on your lighting color (slightly higher reading expected/desired if your lighting has more blue end spectrum.)

How much is a decent Par meter? Unfortunately you may have to be the guinea pig and do trial and error while taking note of your measures.

I would compare your readings to these charts and guestimate with your trial and error.

I would note that I think these charts show a bit high for top end of optimal, I wish they put another color at the 8,000+ line for CO2 supplementation light levels.
Click to expand...
Thanks to both of you! I should be able to get in the ball park using the info you both supplied and then experiment a little. Yep, my lux meter was fairly affordable at ~$150 and PAR meters form a quick look are more like $400-500.

It will take a while but I will post any findings here in time to come. Unfortunately I don't really have the rest of growing dialed enough to consider any findings to be scientific but it should be interesting anyway.

Thanks again!
 
U

Uzzi

Well-Known Member
Just a quick thought...

The tables from Nomofatum above are for HPS. If HPS had the same heat out put as LED; would they still bleach the plants from being too close like LED do? Or in other words, is the bleaching that LED's cause when they are to close to plants do to the amount of Lux/Par received by the plant or due to some other factor produced by LED lighting?
 
justugh

justugh

Well-Known Member
no that i have ever seen and i have bleached plants with HID .........if u were with in 6 inches the plant would bleach on 600w

i have led with in 2 inches of the leave it only makes the upper sets of leaves thicker
 
U

Uzzi

Well-Known Member
Hmm I have read a lot about bleaching from LEDs though? I have two 300s and had previously thought I'd light bleached my plants but again I'm not sure as the rest of my grow isn't dialed in so I can't discount other factors as being the cause of the burn...
 
Stoner 420

Stoner 420

Active Member
nomofatum said:
Par is the more perfect measure, but lux should be very close. Both measures are stongly related especially when the light color is isn't changing. Lux target will change slightly depending on your lighting color (slightly higher reading expected/desired if your lighting has more blue end spectrum.)

How much is a decent Par meter? A decent lux meter can be had for $20-30. A 95% accurate measure should be good enough when the alternative is to go off someone else's readings or buy a much more expensive meter. I would make lux work (it's close enough) or just go with trial and error. Unfortunately you may have to be the guinea pig and do trial and error while taking note of your measures.





I would compare your readings to these charts and guestimate with your trial and error.

I would note that I think these charts show a bit high for top end of optimal, I wish they put another color at the 8,000+ line for CO2 supplementation light levels.
Click to expand...
Can you help with my drivers on Mars Hydro ts3000
 
F

Funbudd

Member
You can download a free app on your phone. I have Photone and it works pretty good. Just make sure you use a defuser per instructions (Piece of paper). Also I have my leds just inches above my plants and leaves have never burned.
 
Stoner 420

Stoner 420

Active Member
I have app tent buddy but at like 2-300 it's a little bit too much for my seeds even like I don't have the lux meter dryer I just don't know how to read it right
 
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