How light spectrum affects nutrient use in plant tissue...

[Capulator]

So I have this tree I am growing and it is surrounded by (4) 1000w bulbs.

2 MH and 2 HPS.

Plant tissue (leaves) being pummeled with HPS light are showing what looks like a P deficiency (brown spotting, purple petioles etc)

Leaves hit my the MH do not show these symptoms. This is on the same plant.

So by this observation I am wondering if an HPS spectrum (more red?) causes the plant to take up more P...

Where the botanists at yo!? I am super curious about this.

 

[souf69]

Cap, Ive always wondered the same thing. I have a friend that uses reds all the way thru from transplant, and he seems to get very good growth. I have always used blues for veg and then reds in pre bloom. I have always read that blue is healthy for grow and red means death soon.

 

[619ster]

Great observation. Working with LEDs I've noticed a lot of this. Under LEDs my plants seem to enjoy more cal-mag (magnesium to be exact as I've only ever had mag def under LEDs). Yes HPS seems to take bloom boosters best, because under other lighting I have often burned my plants a bit when introducing a booster. Under CMH I've had maybe the healthiest plants. T5's as well, and flowered a damn nice plant under cfl's before as well and required the least amount of food. Not any science behind what I say. Just sharing my observations.

 

[Ohiofarmer]

I seem to always get best results when mixing mh with hps with slightly more red spectrum light during bloom and less during veg.

 

[DO IT]

This happened 1 time to me cap... i never figured it out and it never happened again... i lose about 12% on that crop.

 

[Capulator]

This happened 1 time to me cap... i never figured it out and it never happened again... i lose about 12% on that crop.

shit. :facepalm:

Were you running multiple lights as well (hps, MH)?

Here is pikchurz...

HPS: Leaves only doing this that are closer to light.

MH: Same distance leaves. You can see some symptoms but not nearly as bad.

I think I am not feeding enough. I am flushing now and gonna hit them with 1.8EC to be sure. Ill know if I made them worse in a couple days. Plants and flowers look healthy. Coco much better than MPB with no signs of bad health whatsoever but coco has been getting lots of food... MPB I've kept around 1.2 EC.

 

[We Solidarity]

are you foliar spraying? that looks more like spray burn.

 

[ttystikk]

That's not spray burn. I know you pack a lot of plants into a small space so RH will be higher. This will lead to slower uptake of moisture and thus less uptake of nutes. Not sure why it would show more in one light than another, maybe the hps is hotter/closer?

 

[DO IT]

same exact thing... 20k per room sunmasters HPS... ama see if i still have some pic's.

 

[DO IT]

i dont know how well you can see them but check out the fan leaves. I dont know why the site turns the pic's??? The second pic has a big fan there with the brown spot on it.

 

[DO IT]

shit. :facepalm:

Were you running multiple lights as well (hps, MH)?

Here is pikchurz...

HPS: Leaves only doing this that are closer to light.

View attachment 342956

MH: Same distance leaves. You can see some symptoms but not nearly as bad.

View attachment 342957

I think I am not feeding enough. I am flushing now and gonna hit them with 1.8EC to be sure. Ill know if I made them worse in a couple days. Plants and flowers look healthy. Coco much better than MPB with no signs of bad health whatsoever but coco has been getting lots of food... MPB I've kept around 1.2 EC.

I tried it all cap and nothing seemed to make them better so i just went on with the same routine and they finished ok.

 

[DO IT]

cap here is the thread i started when this was going on there are plenty of pic's from the start and as it got worse.

https://www.thcfarmer.com/community/threads/got-spots.56088/#post-1057937

 

[GR33NL3AF]

cap here is the thread i started when this was going on there are plenty of pic's from the start and as it got worse.

https://www.thcfarmer.com/community/threads/got-spots.56088/#post-1057937

What strain?
Have you ran this strain again with better results?

 

[Seamaiden]

Tagged, because I want to know the answer to this question and I've gotta head to Folsom.

 

[tweedy]

Id be interested to see the bulbs at an equal intensity distance, not just equidistant from the plant. That 1000 watt sodium is putting out 40,000 more lumens I'd guess and that is likely having an effect as well. For controls sake if you do experiment with this you should bust out the light meter and get the same lumens per square foot out of em to see if it really still makes a big difference.

 

[pussOGbrah]

i would treat it as either a K def or cal def,.. i think its a def for sure.. Dont think its p..

i really think its K tho..is it old leaves or new?

either way i would raise base and also couldnt hurt to bump the micronutes in your feed, but i doubt its a micro issue.

>>>just my opinion hope it helps

 

[dankworth]

I think tweedy has a good point. Light meter measurements would be great, PAR light meter measurements would be even better.
Increased metabolic rate due to localized increase in light values was my first guess. Thus the deficiency that does not show elsewhere.

 

[Jalisco Kid]

I agree with the above poster,I was off to get this study when he snuck in under the door. Good eye.
I believe it is a calcium caused problem. I was going to suggest you spray a branch today with your c25 then tomorrow night mix a batch of K nitrate,K,silicate,fulvic acid and some kelp just to help with the digestion,or some aminos for the kelp.
P def for me I notice they are crispy leaves with smaller necrosis spots
Anyway on the light spectrum go to UC Davis or TAMU they will have the spectral studies. I found this one which really has nothing to do with your question but is the same area.
JK
Edit: that download took so long another dog snuck in, And I agree with him also. It is why I believe it is a calcium problem as the leaf is not able to up load the Calcium as fast as it's getting locked out/ used.

 

[Capulator]

Id be interested to see the bulbs at an equal intensity distance, not just equidistant from the plant. That 1000 watt sodium is putting out 40,000 more lumens I'd guess and that is likely having an effect as well. For controls sake if you do experiment with this you should bust out the light meter and get the same lumens per square foot out of em to see if it really still makes a big difference.

I will check with my light meter tonight.

I agree with the above poster,I was off to get this study when he snuck in under the door. Good eye.
I believe it is a calcium caused problem. I was going to suggest you spray a branch today with your c25 then tomorrow night mix a batch of K nitrate,K,silicate,fulvic acid and some kelp just to help with the digestion,or some aminos for the kelp.
P def for me I notice they are crispy leaves with smaller necrosis spots
Anyway on the light spectrum go to UC Davis or TAMU they will have the spectral studies. I found this one which really has nothing to do with your question but is the same area.
JK
Edit: that download took so long another dog snuck in, And I agree with him also. It is why I believe it is a calcium problem as the leaf is not able to up load the Calcium as fast as it's getting locked out/ used.

Fuck man I spray Ca25 every week and I am running 60ppm Ca in my tap plus another 120 with the CaNit.

THe other night I hit them with AgSil, Ca 25, MKP, and fulvic!!!

Last night I changed the res and bumped up the K to 230ppm, P at 60ppm, N at 120ppm. Ca @150ppm. Mg @ 50ppm.

pH 5.5-6.2
EC was 1.2 now I am at 1.8.

Flowers look great. Not all plants showing symptoms. Only half in the MPB. ESPECIALLY the cookies. The starfighter just a little here and there, and the FPOG #7 looks perfect.

 

[Capulator]

I think tweedy has a good point. Light meter measurements would be great, PAR light meter measurements would be even better.
Increased metabolic rate due to localized increase in light values was my first guess. Thus the deficiency that does not show elsewhere.

Yeah you know what tripped me out.

Quantrill said under higher light intensities you actually need to feed less. I thought I was wring and asked him to clarify. He clarified.

I need to get at that guy and ask him why, because I have always heard the exact opposite. I figured maybe it was something to do with salt evaporation and leaf scorch.