How to prevent LED bleaching

G

GROYO

Member
Been trying to research this as much as possible to prevent it before it happens. Im building a DIY light with 28 cree xp-e reds run at 700mah and 12 cree xp-g whites (5w) run at 1 ah i think. No lenses cause it'll be in a GL40 tent so i gotta be up close and personal without a lot of headroom. I've heard the higher power LED's (cool white, blue) cause bleaching and have seen the pictures. It makes sense to me, blue light has the most energy, however it is still needed. I've seen a lot of people supplement Iron or cal-mag when running LED's to help combat bleaching. Do you think ill have a problem with bleaching in my 3' 11" H tent? My DIY panel will run at around 80 real watts. in a 16" x 16" area. How close could i get my light to the plants while supplementing cal-mag? do you think im safe to run the white at 1 ah or should i knock it down to .7? The whites are 5w LED's which is why im worried. No lenses but then again LED's are still pretty powerful unfocused too. Thanks!

PS im new, hi all :mrgreen:
 
Endur0xX

Endur0xX

Well-Known Member
4' high is not bad, you can have big container or big rez and have the light way up high 30'' from the top of your container. you scrog 8'' away from the top of your container and you will not have to worry about bleaching with powerful leds. 80 watts in 16x16, it will be a challenge to get 2 oz! just so you know
 
G

GROYO

Member
Endur0xX said:
4' high is not bad, you can have big container or big rez and have the light way up high 30'' from the top of your container. you scrog 8'' away from the top of your container and you will not have to worry about bleaching with powerful leds. 80 watts in 16x16, it will be a challenge to get 2 oz! just so you know
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Think i need more watts? i felt like i was already pushing it with LED's! i can either up the amps on the whites for a 5-10 watt boost and im definitely not opposed to CFL/T5 either. I trust your recommendations Endur0xX, I've been a lurker of yours for some time ;-)
 
Endur0xX

Endur0xX

Well-Known Member
GROYO said:
Think i need more watts? i felt like i was already pushing it with LED's! i can either up the amps on the whites for a 5-10 watt boost and im definitely not opposed to CFL/T5 either. I trust your recommendations Endur0xX, I've been a lurker of yours for some time ;-)
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hehe thank you... well I didnt mean to add more watts ... only getting more than 1.5 oz per sq/ft is a challenge that's all :eyesmoke:
 
foreverflyhi

foreverflyhi

Well-Known Member
It's funny, I never ever once bleach my plants with any of my LEDs? I've once had my mag + 2inch away and no bleach? Just like you said I've seen pictures, but it's never happened to me.
I know your limited on space so I say, start with your light as far as possible and let the plant grow to the light, no adjusting unless u feel it needs to be adjusted
 
Voidling

Voidling

Well-Known Member
It happened to me when my bb2 grew into my led, twice. Stretchy plant. As long as it wasn't touching I had no issue
 
PSUAGRO.

PSUAGRO.

Well-Known Member
Here you go friend >> 001.jpg002.jpg Cree 460/630nm xp-e 3w diodes driven at 700ma @ 29 days since germ.......notice the tops are at three inches from the panel and no bleaching at all(even last round I saw none)..........keep in mind that the primary lens angles on these diodes are all over 100 degrees.....good luck
 
stardustsailor

stardustsailor

Well-Known Member
.keep in mind that the primary lens angles on these diodes are all over 100 degrees.....
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And total ppf is way lower than 500-600 umol/sec ,I might add...
'Bleaching' ,occurs where too much energy* is concentrated in a small surface/area of canopy or buds...
The more energy* ,the faster 'bleaching' will occur...
*( Energy= Power x Time )

Light power has to be distributed,as evenly as possible , all over plant(s),
should be at reasonable amounts (depending on plant's "juvenile photomorphogenesis" and on it's genome )
and should not exceed a proper duration of time irradiated ...(<= according to "wavelength mix" & total flux ... )
 
stardustsailor

stardustsailor

Well-Known Member
I've heard the higher power LED's (cool white, blue) cause bleaching and have seen the pictures. It makes sense to me, blue light has the most energy, however it is still needed.
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Well,as you put the whole matter...Nope...
1 Watt of light at a blue wavelength ,irradiated for 1 sec ,will provide 1 Joule of energy....
1 Watt of light at a red wavelength ,irradiated for 1 sec ,will provide,also, 1 Joule of energy....

It's not blue light ,that has the "most energy"....It's the blue photons ,that "carry" a lot of energy...
But they are way less in numbers i.e from red photons ,for the same amount of energy given.....
So ..
x Watts(Power) of light is either a lot of photons with low energy each,or few only photons with a lot of energy ....
Blue at i.e. 450 nm has (approx ) 3.75 umoles of photons per Watt of light ... (6.022 x 10^23 x 3.75 x 10^-6= 22.5 x 10^17 photons. )
While red at 660 has (approx ) 5.5 umoles of photons per Watt of light .... (6.022 x 10^23 x 5.5 x 10^-6= 33.1 x 10^17 photons. )
There's a...small..... difference of 1.060.000.000.000.000.000 photons....But blue photons carry more energy ,each....
So..Nope...
If same power( in Watts ) is applied for same duration...
Total energy ,remains the same.....
1 joule for both blue & red light ,for every output Watt .......
 
G

GROYO

Member
Hey thanks guys this has helped comfort me a lot baha. Psuagro especially, I had the Hans panel in mind when i designed my own.
 
jubiare

jubiare

Active Member
Hey groyo nice project best of luck!

You shouldn't have bleaching problems, especially if you don't pack up the diodes all together too much! As pointed out to you already, degree angle of the diodes you chose allow for more closeness:)

You are underdriving cree xpg at 700mA, so you are spot on with 1000mA! You can go up to 1100 with no problems and good compromise flux/heat!

I would drive the reds at 600mA though, but you are fine at 700 it's nothing excessively bad given good heat dissipation management!

Enjoy:)
 
Fonzarelli

Fonzarelli

Active Member
Endur0xX said:
hehe thank you... well I didnt mean to add more watts ... only getting more than 1.5 oz per sq/ft is a challenge that's all :eyesmoke:
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Do you ever grow with just straight LEDs? Or do you only use them as supplement. I'm pretty sure I've seen a HPS or MH in your setup before.
 
budman111

budman111

Well-Known Member
GROYO said:
How close could i get my light to the plants while supplementing cal-mag?

I would stick with the manufacturers distance recommendation and lower VERY slowly day by day but something to remember is a severe calcium deficiency and you can all but kiss bye to your crop.
Click to expand...
 
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