problems with quantum boards(yellowing)

[bigpeter]

These 2 dinafem Industrial Plants are now 3.5 months old they've been kept in small pots in coco constantly cut back to keep them small. They're under 100 watts of cheap warm white shop leds. I will be putting one or maybe both of them under my SF2000 at the end of my current grow about 2 weeks time.. It'll be interesting to see what happens

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[DiverDave]

I hope you take care to ween them into the higher light , first by dimming it if you can and start with light high and work it down over 4 or 5 day .. and show us all you did it right

DD

 

[farm3r]

Hi,

Light height is fine then

How much Mg did you give them per litre? Your plants need a lot, plus iron and trace elements. Sometimes Mg and iron deficiency look the same.

Did your plants start off losing colour like the picture of the plant below?

View Image

This is a picture of my Northern Lights under the QB. This was the start of a Mg and (maybe) an iron deficiency. I corrected it by adding CalMag for every watering until the problem disappeared, and it took a while. I don’t like using mineral CalMag and have since found an organic substitute. At the time I knew I had to fix the problem fast. The brand I used had Mg, Cal, Iron plus trace elements.

Your plants still need N during flower. When the plant transitions from vegetative growth to flowering, you should still be feeding Nitrogen feed so the plant has enough throughout flower, at least two weeks into the flowering period depending on variety. I found my plants under QBs needed more. I had to completely change my feeding regime under QBs!

I’m no longer using QBs because I wanted something more powerful and opted for single led cob units that I could have at different heights depending on plant height.

I’m still not sure what medium you’re using as I haven’t read the entire thread. I grow organically in soil and the above worked for me. If you’re hydro or coco then your problems might be PH/nutrient lockout.

@Kalbhairav what brand/product do you use that has cal/mag + iron?


I saw someone in this thread used Botanicare cal/mag + which had immediate result.


I too had issues with inter-veinal yellowing and burnt leaves due to QB's. Even at recommended distance and full blast, I'd burn the hell out of them.


In additional to additional cal/mag plus iron?, one needs to slowly dim the light so that the light intensity increases as flowering continues. Don't move the plants from one light source to QB's at full blast. Use the lux meter app on your phone for rough estimate. I converted lux to PPFD and use recommended PPFD values for different stages of growth, but the leaves still burned. So, take that recommendation with grains of salt.


I'm surprised no one mentioned VPD in this thread. Get your VPD right so that the plants can transpire (aka taking up nutes) at higher rate in order to keep up with the light. This means one need to always adjust the environment for different stages of growth.


Also, with QB's, the environment needs to run at maybe 2 to 3 C temperature higher than normal since QBs don't give out as much heat. This also gets the plants to run at higher metabolism inorder to take up nutes at higher rate.


I'm still trying to adjust and dial in to how to grow with QB's.


BTW, for cal/mag, I add extra gypsum and dolomite lime to my soil mix. Then I would also top dress additional gypsum, dolomite, and epsom salt. Now, I am very interested in those cal/mag plus iron products that a couple of you guys are using and saw immediate result in dealing with yellowing/burnt leaves. In case some of you don't know, inter-veinal yellowing is mag deficiency and burnt/dead area is necrosis due to cal deficiency.

 

[SuperBadGrower]

^ I don't know commercial products but the easiest & cheapest thing is probably to just get you some iron DTPA and experiment with that.

 

[Kalbhairav]

Hi farm3r,

The product I used (the non organic one) was Plant Magic Magne-cal+
This product has cal, Mg, Iron, plus trace elements.

I grow in soil, not hydro.. so might be different for you.
I never had any burning.
I don’t use any light meter.
I veg and flower under the same 3.5k light

Through veg, everyday I would increase light intensity by roughly 5-10%. Light would be at 100% power before I switch to flower. This way the plant has already adjusted to the power of the light.

When a plant is in veg, it recovers easier than when flowering. I prefer to not mess with light intensity during flower. I just want full power for all of flowering

Hope that helps

Good luck

@Kalbhairav what brand/product do you use that has cal/mag + iron?


I saw someone in this thread used Botanicare cal/mag + which had immediate result.


I too had issues with inter-veinal yellowing and burnt leaves due to QB's. Even at recommended distance and full blast, I'd burn the hell out of them.


In additional to additional cal/mag plus iron?, one needs to slowly dim the light so that the light intensity increases as flowering continues. Don't move the plants from one light source to QB's at full blast. Use the lux meter app on your phone for rough estimate. I converted lux to PPFD and use recommended PPFD values for different stages of growth, but the leaves still burned. So, take that recommendation with grains of salt.


I'm surprised no one mentioned VPD in this thread. Get your VPD right so that the plants can transpire (aka taking up nutes) at higher rate in order to keep up with the light. This means one need to always adjust the environment for different stages of growth.


Also, with QB's, the environment needs to run at maybe 2 to 3 C temperature higher than normal since QBs don't give out as much heat. This also gets the plants to run at higher metabolism inorder to take up nutes at higher rate.


I'm still trying to adjust and dial in to how to grow with QB's.


BTW, for cal/mag, I add extra gypsum and dolomite lime to my soil mix. Then I would also top dress additional gypsum, dolomite, and epsom salt. Now, I am very interested in those cal/mag plus iron products that a couple of you guys are using and saw immediate result in dealing with yellowing/burnt leaves. In case some of you don't know, inter-veinal yellowing is mag deficiency and burnt/dead area is necrosis due to cal deficiency.

 

[bigpeter]

As promised here are 3 pics of two industrial plants that were put under my spider farmer 2000 12 on 12 off after spending 12 weeks under a 100 watt led shoplight 16 on 8 off. The light was dimmed to around half power for a couple of days and to full power after that. The plants showed no signs of stress and are doing ok.

 

[DiverDave]

As promised here are 3 pics of two industrial plants that were put under my spider farmer 2000 12 on 12 off after spending 12 weeks under a 100 watt led shoplight 16 on 8 off. The light was dimmed to around half power for a couple of days and to full power after that. The plants showed no signs of stress and are doing ok.


View Image


View Image


View Image

Looking good

DD

 

[bigpeter]

I think this may have a lot to do with things, I add root stimulators and bennies at every feed. Good roots mean good healthy plants

 

[Kalbhairav]

I wouldn’t be able to comment from the pictures of the plants under the lights.

From the 3 pics with the light bouncing off them I would say those plants are Mg deficient. Very light green top growth of the canopy fading out. But it may be just the light.

 

[DiverDave]

Looks like a nice root ball so you know the growth should be good.
Let us know what the final dry weight is please.

DD

 

[bigpeter]

different camera settings, they look like this

 

[Klompen]

At least one of those pics earlier in the thread was clearly light-bleaching. Without all the UV and IR, LED lights can be placed a lot closer to the plants and sometimes that means you're overloading them with the wavelengths the light does emit.

 

[bigpeter]

27 days into flowering, a few leaves curling not sure why, temps dont go above 28C, plenty of air extraction. Everything else is OK. Lights at 100%.

 

[IckySticky]

Hi,

Light height is fine then

How much Mg did you give them per litre? Your plants need a lot, plus iron and trace elements. Sometimes Mg and iron deficiency look the same.

Did your plants start off losing colour like the picture of the plant below?

View Image

This is a picture of my Northern Lights under the QB. This was the start of a Mg and (maybe) an iron deficiency. I corrected it by adding CalMag for every watering until the problem disappeared, and it took a while. I don’t like using mineral CalMag and have since found an organic substitute. At the time I knew I had to fix the problem fast. The brand I used had Mg, Cal, Iron plus trace elements.

Your plants still need N during flower. When the plant transitions from vegetative growth to flowering, you should still be feeding Nitrogen feed so the plant has enough throughout flower, at least two weeks into the flowering period depending on variety. I found my plants under QBs needed more. I had to completely change my feeding regime under QBs!

I’m no longer using QBs because I wanted something more powerful and opted for single led cob units that I could have at different heights depending on plant height.

I’m still not sure what medium you’re using as I haven’t read the entire thread. I grow organically in soil and the above worked for me. If you’re hydro or coco then your problems might be PH/nutrient lockout.

Thanks bud, had same problem on a test run last time in straight promix cup and didn't calmag until transplant. Same problem again so it must be calmag missing from the getgo. Your picture just woke me up