led light burn ...lux meter?

taproot

Well-Known Member
Hello gents, I'm still having issues with my new Led adventure and wanted to point out a few things I've been trying and noticing reproducible. The summary is when I put my plants under the Led light I built the leaves start to turn yellow over time but under the hps they start to green up. I have a older thread here that has a lot of details but basically what I found out after transplanting and trying a few different ferts including scotts slow release granules is that I don't think it's a fert issue or a too much issues as the slow release works great under the hps. The pictures I have are plants in miracle grow soil mix with a little of the ocomote slow release fert, they looked great about 10 days ago , nice and lush green , when I pulled them from under the hps and put them under the led light. After a week or maybe two the leaves will start to lighten up as you can see and if I continue to keep them under the led light they eventually become yellow. This is repeatable over and over again..under the hps they thrive but under the led they yellow out and get sick. In the beginning it looks like a nute deficiency but end stages it looks like bad fert burn ...but again same everything under my hps they do well. I'm thinking this is light burn and it eventually gets worse and worse as it bleaches out the chlorophyll. I bought a Lux meter to compare the hps to the led but then found out you can't really measure led/s with a lux meter very accurately but might be able to get into the ballpark. I'm running 9x 2Ft Bridgelux EB Gen2 3500K led strips on a foot print of 24" W 18" deep. The driver is a HLG-185H-c1050 hooked up to a killawatt so I can measure wattage. They seem to get burned with only 130W - 150W and a lux reading of 20000 -- 22000K via the dr lux meter. The led lights are about 3 ft up from the canopy; the hps would be a 400w about 3 ft above as well for a comparison. The environmentals 77-82F with 35 to 45% humidity. I've grown a few times with decent success but always used hps for hempy and DWC and didn't have this issue. Has others experienced this coming from hps going to Led strips? Again these plants I'm attaching looked good just 5 or six days ago and I noticed the tops starting to get lighting going on again. Is this light burn? Are we supposed to use calmag with leds or is this a myth? Does anybody have lux readings they can share for veg and flower, maybe one day I can get a par meter.


https://www.amazon.com/Dr-Meter-LX1330B-Digital-Illuminance-Light/dp/B005A0ETXY/ref=sr_1_4?keywords=lux+meter&qid=1552181361&s=gateway&sr=8-4
 

Turpman

Well-Known Member
I run EBs and don't seem to have any burn problems. And I run close like 1" Looks more like the plants can't keep up with nutes. I would just dial them back and get your humidity up. Let the roots catch up.
 

Chip Green

Well-Known Member
I have the exact same LUX meter, and run multiple 2'x2' panels of 8x EB series 3500K 560mm (mine are gen1) with those exact same HLG185-1050 drivers... Ive had VEG LUX as high as 30K Lux, and I routinely flower with 45-50K.
I experienced "bleaching" one time, on a few upper leaves, with a larger EB panel, that could get to 75K Lux at 4" from canopy.
I find the new growth happening so fast, they often appear to be deficient. Magnesium seems to be consumed at an accelerated rate.
Some mediums, and or nutrients will lack proper Calcium and Magnesium levels. I basically water only in FFHF for up to 8 weeks in 7 gal, with 200ppm tap, and occasionally give some Epsom for the Magnesium.
Calcium carbonate in the tap water, Magnesium sulfate from the Epsom= Cal-mag.
 

taproot

Well-Known Member
I run EBs and don't seem to have any burn problems. And I run close like 1" Looks more like the plants can't keep up with nutes. I would just dial them back and get your humidity up. Let the roots catch up.
What's your lights dimensions, how many strips, what wattage are you running at, which driver are you using? What style are you growing hydro / soil? Which EB strips are you using 3500K? What nutes are you using and the dose for veg and flower? Are you using tap water, I'm using tap which has always worked well for me with a 250-300 ppm at about 7.0ph. What's your room / cab temp and humidity? Do led grows need to be feed less compared to hps as in ppm? Sorry for all the questions just trying to compare.
 

taproot

Well-Known Member
I have the exact same LUX meter, and run multiple 2'x2' panels of 8x EB series 3500K 560mm (mine are gen1) with those exact same HLG185-1050 drivers... Ive had VEG LUX as high as 30K Lux, and I routinely flower with 45-50K.
I experienced "bleaching" one time, on a few upper leaves, with a larger EB panel, that could get to 75K Lux at 4" from canopy.
I find the new growth happening so fast, they often appear to be deficient. Magnesium seems to be consumed at an accelerated rate.
Some mediums, and or nutrients will lack proper Calcium and Magnesium levels. I basically water only in FFHF for up to 8 weeks in 7 gal, with 200ppm tap, and occasionally give some Epsom for the Magnesium.
Calcium carbonate in the tap water, Magnesium sulfate from the Epsom= Cal-mag.

These are the strips I bought are they the same as yours?

https://www.digikey.com/product-detail/en/bridgelux/BXEB-L0560Z-35E2000-C-B3/976-1734-ND/7907663

Do you use extra calmag with your feeding, how are you growing, what are you environmentals? I'm not sure what FFHF means. Thanks for your input!
 
Last edited:

taproot

Well-Known Member

Turpman

Well-Known Member
I use18x 4’3500 flower 600w hlg 4’x4’ area. Cranked at the end of flow. Close to tops.

4x4’ 3500+4000 mix veg. 16”x4’area can’t remember what driver off hand but I’m running about 50% on the pot.
Currently running veg. 20000 lux at plant tops 2” away. From cuttings about 10”tall. Just a cheep Chinese meter.
Mid 70s humidity 60-70.
Flood and drain. GH trio nutes. I error on the low side as far as PPM. RO water. No calmag currently. I do get some yellowing when I go from cutting dome to the f+d table. I keep a clear dome over the rooted cutting for a bit to dim the light and hold humidity.
Like I said I don’t think it’s your lighting per say. More lack of nutrient uptake. What’s your PPM runoff?
 
Leds typically bump up the cal/mag requirements. Check ph and ppms, make sure everything is kosher there. If anything id say the lights are too far away from those lights, not too close. Ive always kept my leds within 2 feet, as close as i can get them without seeing bleaching.

Also, ive never had issues with leaves bleaching, only bud tips (they literally bleach out white, but continue growing relatively normally. Ive seen claims of thc%s in the 30s from these, but who knows. Ill prob send a few buds out to find out for myself once things get chopped)
 

Turpman

Well-Known Member
I have read light distance should equal the spacing on strips.
My ideas is run close and turn down. Less rotations of the power meter LOL
 
I have read light distance should equal the spacing on strips.
My ideas is run close and turn down. Less rotations of the power meter LOL
The qb96s do a great job mixing the best of both worlds! Plus being able to run up over 200w passive...cant wait to build my room and have some real space to experiment with. 288s, 96elites, cmh, hps all laying arpund right now. Who knew this mj thing would really turn into an obsession with light?

I really want to get the cmh running with a few 96elites and see what happens...
 

taproot

Well-Known Member
I use18x 4’3500 flower 600w hlg 4’x4’ area. Cranked at the end of flow. Close to tops.

4x4’ 3500+4000 mix veg. 16”x4’area can’t remember what driver off hand but I’m running about 50% on the pot.
Currently running veg. 20000 lux at plant tops 2” away. From cuttings about 10”tall. Just a cheep Chinese meter.
Mid 70s humidity 60-70.
Flood and drain. GH trio nutes. I error on the low side as far as PPM. RO water. No calmag currently. I do get some yellowing when I go from cutting dome to the f+d table. I keep a clear dome over the rooted cutting for a bit to dim the light and hold humidity.
Like I said I don’t think it’s your lighting per say. More lack of nutrient uptake. What’s your PPM runoff?
I've not been checking the ppm or ph in soil...I never have. I thought you really didn't have to worry to much about this in soil. I was trying to get mother plants and wanted it to be easy so I figured soil would be the best approach ...so I went down to walmart and bought some six inch pots which is about a qt of volume and drilled a hole about one inch up from the bottom. I then put about a cup of washed lava rock in the bottom then I fill up the rest of the pot with MG potting soil that is suppose to have six months of fert already in the soil but I also put about 3 tbs of that osmocote slow release fert in there. Basically just a soil hempy bucket with slow release ferts.
I've only generally checked my dwc or hempy hydro grows for ppm and ph. I just watered two of them and until the point the water started running out of the hole then I tip them over a little to drain the small reservoir. One had a ppm of 200ish and the other had a ppm of 305. The ph was 5.7. I checked my tap water and it's coming out at 200 ppm at a ph of 6.8. The ppm seems low but maybe it's the slow release ferts that's breaking more down in the soil...I'm not sure a runoff test would be accurate for this but I don't know.
 

OneHitDone

Well-Known Member
I've not been checking the ppm or ph in soil...I never have. I thought you really didn't have to worry to much about this in soil. I was trying to get mother plants and wanted it to be easy so I figured soil would be the best approach ...so I went down to walmart and bought some six inch pots which is about a qt of volume and drilled a hole about one inch up from the bottom. I then put about a cup of washed lava rock in the bottom then I fill up the rest of the pot with MG potting soil that is suppose to have six months of fert already in the soil but I also put about 3 tbs of that osmocote slow release fert in there. Basically just a soil hempy bucket with slow release ferts.
I've only generally checked my dwc or hempy hydro grows for ppm and ph. I just watered two of them and until the point the water started running out of the hole then I tip them over a little to drain the small reservoir. One had a ppm of 200ish and the other had a ppm of 305. The ph was 5.7. I checked my tap water and it's coming out at 200 ppm at a ph of 6.8. The ppm seems low but maybe it's the slow release ferts that's breaking more down in the soil...I'm not sure a runoff test would be accurate for this but I don't know.
Haven't read this whole post but you could be having issues with soil being too wet in "hempy" causing that osmocote to release too quickly.
I know where I am on the cool coast with lot's of rain the nursery's do not like or use osmocote do to the high moisture levels :peace:
 

Turpman

Well-Known Member
I've not been checking the ppm or ph in soil...I never have. I thought you really didn't have to worry to much about this in soil. I was trying to get mother plants and wanted it to be easy so I figured soil would be the best approach ...so I went down to walmart and bought some six inch pots which is about a qt of volume and drilled a hole about one inch up from the bottom. I then put about a cup of washed lava rock in the bottom then I fill up the rest of the pot with MG potting soil that is suppose to have six months of fert already in the soil but I also put about 3 tbs of that osmocote slow release fert in there. Basically just a soil hempy bucket with slow release ferts.
I've only generally checked my dwc or hempy hydro grows for ppm and ph. I just watered two of them and until the point the water started running out of the hole then I tip them over a little to drain the small reservoir. One had a ppm of 200ish and the other had a ppm of 305. The ph was 5.7. I checked my tap water and it's coming out at 200 ppm at a ph of 6.8. The ppm seems low but maybe it's the slow release ferts that's breaking more down in the soil...I'm not sure a runoff test would be accurate for this but I don't know.
Sounds like low nutes. If your going for mother’s low nutes is what you want. Slow growth, less repotting, better cuttings. Turn light down, light fert is what I would do. They will stretch more and make for earlier cuttings and cuts may do better with lower nitrogen in them.
 

taproot

Well-Known Member
Haven't read this whole post but you could be having issues with soil being too wet in "hempy" causing that osmocote to release too quickly.
I know where I am on the cool coast with lot's of rain the nursery's do not like or use osmocote do to the high moisture levels :peace:
Honestly I hate all the mess of soil and perlite etc. The best grow I've ever had was with dwc but I can't pull that off in the summer as I can't afford to run the AC all day and it's generally in the 80's in the grow room which is why I'm trying to get LED/s to work for me. Our summers are pretty hot with average temps in the 100's F for several months which puts my house about 82F without any lights running. The DWC was nice because I knew what level the ph and ppm was very easy. And, I loved no soil or perlite getting spilled and when I was done I just drained the tub and there's was not mess to get rid off except some roots.
 

OneHitDone

Well-Known Member
Honestly I hate all the mess of soil and perlite etc. The best grow I've ever had was with dwc but I can't pull that off in the summer as I can't afford to run the AC all day and it's generally in the 80's in the grow room which is why I'm trying to get LED/s to work for me. Our summers are pretty hot with average temps in the 100's F for several months which puts my house about 82F without any lights running. The DWC was nice because I knew what level the ph and ppm was very easy. And, I loved no soil or perlite getting spilled and when I was done I just drained the tub and there's was not mess to get rid off except some roots.
I don't like the "unknown" of soil in pots either.
Don't know if you can get Royal Gold Tupur where you are but here on the west coast it's cheaper than buying bags of perlite and you run it just like hydro.
Throw some GH Flora Nova Grow on them and be done. Maybe CaliMagic to deal with heavy mag strains and led BS :peace:
 

taproot

Well-Known Member
Sounds like low nutes. If your going for mother’s low nutes is what you want. Slow growth, less repotting, better cuttings. Turn light down, light fert is what I would do. They will stretch more and make for earlier cuttings and cuts may do better with lower nitrogen in them.
Yes, I'm going for mothers. I'm older and don't like the high THC strains of today so I'm strain hunting for strains that help my nerve / muscle and joint inflammation pain without causing anxiety. Most of what I have is CBD.
 

Turpman

Well-Known Member
I can’t grow I’m dirt either. Tried DWC root rot got me. Went to flood and drain and it’s looking great. No worries about res temp or aeration. I do plan on using some worm compost this summer with outdoor to see how it goes.
 
>
Top