Led distance/light burn

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ReggieDobson

Active Member
Hi guys I’m in the fifth week of flowering and I’ve got Lumatek ats pro 300w led. Tent size is 3x3x6 so I hung it 12 inches from plants canopy and thats the highest I can go. I had ran the light at 75% with temp being 24C but yesterday I dimmed the light to 100%, the temp now is 26C, im just wondering if i wont fry them with that light being as 12 inch distance, maybe I should go back to 75% (which would be approx 230w), thoughts ??
 
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ReggieDobson

Active Member
amneziaHaze said:
i talked to some people most of them say 30cm. but let me know if it works or doesnt
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I had them at 100 on beginning of flowering and I think I had some light burn that’s why I dimmed it to 75% but back then I had the light slightly closer than 30cm so yesterday I put it but higher it a bit so it’s exactly 30cm from the tallest canopy so I see how it goes today, if id notice any light stress then probably I’d have to go back to run my light at 75%
 
Moflow

Moflow

Well-Known Member
Sounds like you don't have much headroom to play with. - 12"
Probably best to dim the light down a bit again .

Full blast at 16" looks optimum from their Par map.
For flowering you need around 800 - 1000
ATS300Pro_720x.png
You could maybe bend the branches down with string to give yourself more distance between light and canopy.
 
Rurumo

Rurumo

Well-Known Member
I've seen significant light bleaching with some individual plants at 80% AND 16 inches with one plant, while the plant next to it was perfectly happy. Ideal light distance in your particular light conditions will depend on the individual plant (genotype.) So if you only have 12 inches, you have two options-lower the %, or supercrop your plants to create more distance. With 300 watt bar lights a good starting point in flower is 80% and 20 inches distance, just to give you an idea of what I've seen work well. It's easier to start with slightly less light than ideal, and dial in from there, than to burn your plants and dial in from a point of damage. VPD, nutrients/media style, air circulation, co2 level, etc all influence how much light your plant can "take."
 
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ReggieDobson

Active Member
Rurumo said:
I've seen significant light bleaching with some individual plants at 80% AND 16 inches with one plant, while the plant next to it was perfectly happy. Ideal light distance in your particular light conditions will depend on the individual plant (genotype.) So if you only have 12 inches, you have two options-lower the %, or supercrop your plants to create more distance. With 300 watt bar lights a good starting point in flower is 80% and 20 inches distance, just to give you an idea of what I've seen work well. It's easier to start with slightly less light than ideal, and dial in from there, than to burn your plants and dial in from a point of damage. VPD, nutrients/media style, air circulation, co2 level, etc all influence how much light your plant can "take."
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I’m in the fifth week of flowering so supercroping isn’t an option at this stage. I’m gonna lower the % down back to 75 and do you think I should run on thatlevel till the end or increase percentage in last 3-4 weeks of flower ?
 
amneziaHaze

amneziaHaze

Well-Known Member
Moflow said:
Sounds like you don't have much headroom to play with. - 12"
Probably best to dim the light down a bit again .

Full blast at 16" looks optimum from their Par map.
For flowering you need around 800 - 1000
View attachment 5236080
You could maybe bend the branches down with string to give yourself more distance between light and canopy.
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where did you get this photo do they have this for less %

edit
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1670683228165.png
 
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ReggieDobson

Active Member
I’m so f***in confused to be fair cus I had more read about them distances and seen the charts as well and there are just so many info. Few people on some other forum said that they usually run their leds 300w on full strength having them 12 inches from the canopy. I rotated them a little so the tallest buds are on the edges but generally I’ve had some nutes lockout issues and I flushed them yesterday but todays morning I’ve noticed this on the leaves (see photos) so I’m not sure if that’s the effect of the lockout progressed since yesterday or if that’s the light. It’s weird because normally only two of my plants has canopy tall enough to reach te distance around 32cm whereas the other one is exactly 18 inch - 16 inch so I don’t know if I should lower the percentage back to 75% cus thats a light Burn there starting or fxxk knows. It weird cus it seems like only top fan leaves are affected
 

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hotrodharley

hotrodharley

Well-Known Member
ReggieDobson said:
I’m so f***in confused to be fair cus I had more read about them distances and seen the charts as well and there are just so many info. Few people on some other forum said that they usually run their leds 300w on full strength having them 12 inches from the canopy. I rotated them a little so the tallest buds are on the edges but generally I’ve had some nutes lockout issues and I flushed them yesterday but todays morning I’ve noticed this on the leaves (see photos) so I’m not sure if that’s the effect of the lockout progressed since yesterday or if that’s the light. It’s weird because normally only two of my plants has canopy tall enough to reach te distance around 32cm whereas the other one is exactly 18 inch - 16 inch so I don’t know if I should lower the percentage back to 75% cus thats a light Burn there starting or fxxk knows. It weird cus it seems like only top fan leaves are affected
Click to expand...
Buy a cheap quantum PAR meter and it ends the guessing immediately.
 
hotrodharley

hotrodharley

Well-Known Member
ReggieDobson said:
Right that’s what I’m gonna do. So is it 50k
Tops I should aim to?
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That’s not a PAR rating. Get a quantum PAR meter. Not a light meter for photography. Then avail yourself of the DLI calculator on the Photone website. You’ll be amazed how easy it gets doing those two things.
 
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