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

[Capulator]

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

hahah people in yoru thread say P and K

People here say K and Ca

My first thought was P...

Ca starts with tip browning and moves to brown spotting. This has very little tip or margin burn and the necrosis starts more at the center vein. Plus the purple petioles. I will snap some pics of the GSC leaves and you will see how fucked they are.

 

[Capulator]

Anyway guys as much as I want to solve the problem of my semi sick plants, I also want to look at spectrum, and how plants are using strong light/weak light, HPS/MH etc.

Try to get to the bottom of this "mystery" you know. I am gonna ask quantrill to look over here right quick. He is good with nutes too.

 

[Jalisco Kid]

I think your K is getting locked up usually because of calcium. That is why I suggested spraying a branch with proper amount of Cal then spray your K. I too believe in lower nutes. with more light more photosynthesis , more N and aminos getting made/used. more sugars etc. Hope you find out what works for you. JK

 

[Jalisco Kid]

In post 18 the last line I meant to put K instead of Calcium but I can not edit it.JK

 

[Capulator]

I think your K is getting locked up usually because of calcium. That is why I suggested spraying a branch with proper amount of Cal then spray your K. I too believe in lower nutes. with more light more photosynthesis , more N and aminos getting made/used. more sugars etc. Hope you find out what works for you. JK

You think maybe too much Ca causing K lockout?

 

[ttystikk]

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.

I can guess why; basically amounts to needing a lot of water under such intense conditions. Thus, higher light intensities might tend to push effective VPD down, thus affecting the optimal feed strength and- my guess here, but it follows- CO² uptake. Therefore, I believe that the way to help the plant handle very high light pressures effectively lies in making certain RH levels are high, even around 75%. This is in addition to the usual advice of fans blowing air across the plants, CO² augmentation, etc. I believe the higher humidity helps protect the plant. Equatorial plants get the most intense sunlight, and the places they tend to do best tend to be humid.

 

[Capulator]

My RH is 68% and my temps are 78. CO2 at 1000ppm.

 

[ttystikk]

My RH is 68% and my temps are 78. CO2 at 1000ppm.

That seems to be in order to me... this may affect your honeycomb setup more, due to intense lighting and proximity to the bulbs.

 

[DO IT]

No

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

No GL it was a strain I put together and it did not get tall enough for me so I caned it... I still have beans though just in case. I never figured it out.... cap I give about 300ppm of calmag+ so I don't think that's the problem but I'm not sure... it only happened once and I have not seen I again.

 

[Seamaiden]

In post 18 the last line I meant to put K instead of Calcium but I can not edit it.JK

If you'd like I can edit it for you.

You think maybe too much Ca causing K lockout?

Yes, it would make a lot of sense. Look at the mineral wheel.

Pay closest attention to the arrows on the lines, they denote synergy or antagonism/interference. Look at the line that's connecting K with Ca. They are antagonistic to each other.

 

[obsoul33t]

when K is in excess it not only is antagonistic to ca but magnesium and nitrogen too ..

 

[Quantrill]

the more water that a plant transpires, the lower the EC of the nutrient solution should be.

 

[Capulator]

the more water that a plant transpires, the lower the EC of the nutrient solution should be.

Why?

when K is in excess it not only is antagonistic to ca but magnesium and nitrogen too ..

Yeah. I was running around 24ppm P so that's why I am thinking P. Plus the cookies are feeling it more than the rest. I 3 coco cookie trees in an MPB on one side, and 3 MPB cookie trees on the other side. Both sides are in the same room and the same lighting. The coco is crushing it. The MPB sucks. I know it's nutes. I have been feeding the MPB exactly half of the coco. I think next time I will feed them the exact same just to see what happens.

coco cookies:

MPB cookies (yeah I had some thrips I ignored for a while... they are all dead now):

Here is another MPB plant doing perfectly. The FPOG #7:

and some MPB starfighter doing just fine on 3/4 of the sides (MH sides)LOL:

I get a lot less shock from the coco when I move them in to the big girls room as well.

Anyway... back on topic.

I want to know why the plants started showing signs of what I think is P deficiency where the HPS was hitting them FIRST. Whether it's light intensity, spectrum, or what. All bulbs are 1k.

 

[Quantrill]

it has been shown that spectral quality of the light can affect the transpiration rate of the plant.

The CWX and GLF light sources increased

Ca uptake as compared to HPS (Table 1).

Since Ca uptake is related to the transpiration

flux (Armstrong and Kirkby 1979; Banuelos

et al. 1985) , the lack of blue in the HPS light

spectrum could explain our results. Indeed,

Matsui et al. (1981) have shown that transpiration

is affected by light quality in the visible

range and that blue light is more effective, and

green light less effective than red in

stimulating stomatal opening.

source:


whether or not that is what is causing your problems, or how you can use htat info to correct it, is beyond me.

 

[Jalisco Kid]

When plants transpire more they bring in more water, They can filter out some macros but it is still getting pulled up for the plant to cool and gas exchanges. JK

 

[clockworx]

I have the same issue on a clone that Im pushing as a test before a large run, I feel like the extra heat jamed up my calcium and k, started to get those brown spots and the leaves looked like paper, but the laser gun only says 82 for leaf temp but the light is super intense. So I went hunting thru NASA test for space crops and found that red light made calcium 140% more available is some plants and others dropped by 40% depending on what was being grown.. they also said that plants were in better health and had a higher dry weight when green light was used with red and blue, noting that green light is reflected but the small amount that is used by the plant made a noticable difference in health....I gave my pot a lite rinse and made a gallon of 1.5 tsp 2-0-0 calmag and 1.5 tsp pro-tekt and moved the plant into a more shaded area for 5 days and the color was better and brown spots stopped.....

 

[clockworx]

Its crazy how little information there is on such an amazing plant......people need to stop opening seed banks and start doing research.....everyone says they are for the plant and movement but all you really see is people making stupid shit to sell and make money.....Its sad that we have to read about corn and grape crops and then try to link it to cannabis in order to learn....

 

[Jalisco Kid]

"Yeah. I was running around 24ppm P so that's why I am thinking P."

Depending on what you use but I think you would get more then that with a pH down. That is low especially going into flowering. JK

 

[Seamaiden]

it has been shown that spectral quality of the light can affect the transpiration rate of the plant.


source:


whether or not that is what is causing your problems, or how you can use htat info to correct it, is beyond me.

Ok, I'm digging into this pdf now and they're discussing specific mineral nutrient uptake, or lack thereof, which seems to be quite specific to the issue at hand here. In fact, it's bringing me to wonder a WHOLE BUNCHA THINGS. Like, how come I get purpled/reddened petioles on a given strain when growing her inside, yet outside she's perfect? That's the big one, actually.

 

[clockworx]

Ok, I'm digging into this pdf now and they're discussing specific mineral nutrient uptake, or lack thereof, which seems to be quite specific to the issue at hand here. In fact, it's bringing me to wonder a WHOLE BUNCHA THINGS. Like, how come I get purpled/reddened petioles on a given strain when growing her inside, yet outside she's perfect? That's the big one, actually.

I was just about to say,,,I installed underside lighting on some grows and all the leaves exposed to the light seem to turned pink/red.....I've noticed this on a few other plants at different time through the years.....on my current sour diesel grow I checked the leaves and leaf stems on the underside (normal green) and then added a light that was hitting the side of the plant because it was on the edge of the garden and I watched for a week or so and sure enough, all the undersides of leaves being hit with light from below now have pink/red leaf stems and vains, and its 100% only the leaves that have had prolonged exposure to the underside light.....