N-burn, K-deficency, something else?

[InuYasha]

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

 

[Kupunakane]

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

 

[blancolighter]

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.

 

[InuYasha]

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.

 

[HippyInEngland]

Hello Inu

First things first.

What is your PH reading?

 

[InuYasha]

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.

 

[massproducer]

It looks like a PH problem too me

 

[InuYasha]

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.

 

[massproducer]

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

 

[InuYasha]

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.

 

[massproducer]

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

 

[InuYasha]

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?

 

[InuYasha]

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?

 

[trillions of atoms]

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.

 

[BuddyLuv]

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

 

[InuYasha]

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)

 

[InuYasha]

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.

 

[BuddyLuv]

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.

 

[InuYasha]

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?

 

[Weeddog]

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.