# N-burn, K-deficency, something else?



## InuYasha (Nov 24, 2008)

I have 2 of my 9 1-month old CH9 Jack plants that don't seem to want to grown and green up like their sisters.  There is browning at the edges of the older leaves and some burn spots on them as well.  

I was told that it could be N-burn, but after reading the trouble shooter I think it could be a potassium deficiency.

600W MH-Conversion (72,000 lumens) about 22 inches from top of tallest plant, maybe 25 inches from the 2 problem plants.  

GH Lucas formula (5M-10B) at 3/4 strength.  PPM=470 ph=5.8. 







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Jorurnal: http://www.marijuanapassion.com/forum/showthread.php?p=363697#post363697


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## Kupunakane (Nov 24, 2008)

Yo Ho InuYasha,

  Just a little something that I found helpful in the past, maybe good for you too.
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remember to replace the x's with the two t's , and hope this will be of some little help to ya.

smoke in peace
KingKahuuna


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## blancolighter (Nov 24, 2008)

Looks more like a deficency to me man. Looks too pale green to be nute burn with nitrogen. I think you are on the right track with your diagnosis.


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## InuYasha (Nov 25, 2008)

I'm starting to lean towards K-deficiency.  Does anyone know of a good product to use to supply K?  I'm trying take a targeted approach to avoid simply adding more Flora Series nutes.

New mystery burn:





Burn on older leaves:



Plant not too bad looking at a distance :




Input is always valued.


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## HippyInEngland (Nov 25, 2008)

Hello Inu 

First things first.

What is your PH reading?


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## InuYasha (Nov 25, 2008)

Ph is about 5.5-5.8, I'm using a colour-match test kit, so it's a rough estimate.  I ordered a digital meter, it should be here tomorrow.


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## massproducer (Nov 25, 2008)

It looks like a PH problem too me


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## InuYasha (Nov 25, 2008)

Ph stays pretty constant at 5.5.  I'm using the GH Ph colour-test though, so there maybe some inaccuracy.  I'll have a confident Ph reading as soon as my new meter arrives.


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## massproducer (Nov 25, 2008)

What is the PH drift like, how much do you let it drift and how long do you let it stay


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## InuYasha (Nov 25, 2008)

I check Ph and TDS every day after I add top off distilled water.  I'd say the Ph might get as low as 5.3 before I bring it up.  It's a ph test kit, so it is a subjective "yellow-orange" that I call 5.5.  I'm getting a decent meter tomorrow or Friday.


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## massproducer (Nov 25, 2008)

Well that is kind of a problem, the PH should be drifting up where you should leave it for a bit so that the plant can uptake Mg


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## InuYasha (Nov 26, 2008)

That makes perfect sense when I look at the nutrient availability v. Ph charts.

I've been trying to keep mine constant at 5.5.  

How often should I correct the Ph? How much should I let it drift?


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## InuYasha (Nov 26, 2008)

I added some GroTek Pro-Silicate (3.8% soluble potash) to try to raise my K a bit.  I'm also switching nutes to grotek solo-tek.  

After adding the Pro-Silicate (potassium silicate) my Ph jumped from around 5.5 to a bit over 6.5.  How long should I let it run before I bring the ph back down?


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## trillions of atoms (Nov 26, 2008)

HippyInEngland said:
			
		

> Hello Inu
> 
> First things first.
> 
> What is your PH reading?


 


he stated in the first post it was 5.8



I might try a compost tea thats rich in n p and k plus micronutes if the digi ph meter reads correctly. it doesnt look like a burn, i think its an imbalance.


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## BuddyLuv (Nov 26, 2008)

pH problem for sure. I had it on my aurora indicas, because I forgot to check them for a few days.


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## InuYasha (Nov 26, 2008)

I've just noticed what looks like the early stages of this condition on 2 of the really healthy looking plants.  I'm thinking some sort of deficiency.  I'm planing on changing nutes next week.  Maybe these pics will help.

Healthy looking Plants



Signs of trouble on the left plant (Kagura)



Same thing on her neighbor (Eureka)


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## InuYasha (Nov 26, 2008)

BuddyLuv said:
			
		

> pH problem for sure. I had it on my aurora indicas, because I forgot to check them for a few days.



Buddy,  I'm growing a mostly indica strain (ch9 Jack).  What sort of pH should I shoot for?  How much should I let it drift?

I'm trying to keep it at 5.5-5.8 adjusted every day or two.


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## BuddyLuv (Nov 26, 2008)

I am keeping mine at 5.8-5.9 in a DWC at the moment. The new growth has shown no signs of stress since I raised my pH a little. I did have it a 5.6, I am using a Hanna digital monitor. I also added Advanced Cal Mg Grow to the mix as well. Sometimes pH stress can mimic Calcium or Mg deficiency so I figured I would just kill two birds with one stone.


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## InuYasha (Nov 29, 2008)

I came back from Thanksgiving holiday and the plants look nice and full.  There is still yellow / brown spotting on the old growth, but the new growth looks alright for now.  I plan on doing a water change and replacing the GH Nutes with the GroTek SoloGrow tomorrow.  

I have also got a new digital meter.  It takes alot of the guess work out of maintaining my pH.  I was at 6.1 on the full planter and 6.3 on the other planter.  They were at that level for about 2 days.  Following BudddyLuv's advice, I leveled them out to 5.7 and 5.8 respectively.  

I hear alot about allowing the pH drift so the plants can uptake nutrients that are more available at higher pH's.  How much should I allow it to drift and how often should I correct it?


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## Weeddog (Dec 3, 2008)

How is things goin with this one.  I'm curious as to what you find.  I also have this problem with my white widow.  Just cant seem to put my finger on what the problem is.


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## InuYasha (Dec 3, 2008)

I had it narrowed down to pH and a K deficiency.  I got a new pH meter.  I was keeping my pH a bit low, I'm now confident that I have it at 5.8 (really 5.7-5.9 with the +-.1 error).  I added some Gro Tek Pro-Silica because it was the only thing I could find to raise K without adding more N and P.  So far, the new growth seems alright, but most leaves over 2 weeks old show some small amount of burn.  The plants still seem to be growing well, so I'm less concerned.  I'm switching nutes from GH Flora-Series to Grotek Solo-Grow, so I'm hopping whatever deficiency I may have had will be corrected.

Here are the latest pics of the problem leaves:


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## BigSmoke41510 (Dec 5, 2008)

^that helped me out thanks! Im having the same problem, im gonna try to increase my PH a little bit and see what that does, im also using the color test which i am starting to hate lol


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## InuYasha (Dec 5, 2008)

After nearly 6 weeks of very subjective colour matching, I've come to the conclusion that the colour test sucks.  It's fine for getting "in the ball park", but I don't think I've ever guessed within .2 pH of what my meter tells me.  

Maybe it would be good for an interior designer, painter, or someone who can tell at sight the difference between 'creme' and 'eggshell', but sadly I'm not that talented.      

My new growth looks better at a confident 5.8.  Still some light burning / spotting of the older growth, but 80% less sever than before.  I'm also going to try a Ca/Mg/Fe product to see if I can't get 100% spot-free leaves.


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