Flowering Stage - Need Help with Diagnosis - Nute Burn or Potassium?

  • Thread starter ottomangrows
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ottomangrows

ottomangrows

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Hi All,

I'm a new grower working toward my first harvest of 5 plants. Two are looking ill in the flowering stage. (Other three look fine on same feeding schedule.)

I need a little help from experienced growers on:
  1. A diagnosis
  2. How to treat at this stage in the game (if potassium deficiency.)

I am thinking this is either Nute Burn or Potassium Deficiency.

I am going to lower the canna A B nutes to 2 ML per liter of water; .5 ML of Cal Mag per L of Water.

If this is Potassium, how do I adjust (or do I need to add a supplement)?

THANKS IN ADVANCE FOR YOUR GUIDANCE!

THESE ARE NORTHERN LIGHTS AUTOFLOWERS AT 9 WEEKS:
  • LIGHTS: 18 inches above plants
  • WATERING SCHEDULE: What daily with fertigation until run-off
  • WATER PH: 5.75 PH (Coco)
  • SOIL: Coco Coir
  • NUTES: Canna Coco A B (2.5 ML of each nute - per L of Water)
  • OTHER SUPS: Cal-Mag Plus at 1 ML per L of Water
  • TEMP: Steady 70
  • HUMIDITY: Steady 55
  • STATUS: 9 Weeks
  • TYPE: Northern Lights - AUTOFLOWER

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mysticepipedon

mysticepipedon

It's not nute burn and I don't think it's potassium, either. (There may be a touch of nute burn, but it's not your big problem.)

I can't say for sure. Is it possible that your pH fluctuates a lot?
 
ottomangrows

ottomangrows

3
1
It's not nute burn and I don't think it's potassium, either. (There may be a touch of nute burn, but it's not your big problem.)

I can't say for sure. Is it possible that your pH fluctuates a lot?
My PH is pretty steady.

I use an automatic fertigation system that waters 5.75 PH (Coco Coir) every morning for 90 seconds (about 20% run-off).

It is a 20 Gallon system that I only have to refill once a week.

I am very curious, because it is only affecting 2 of 5 plants and they are all on the same feed schedule/system.

The two plants affects are a Northern Light and a Blue Dream. I have another Northern Light and Blue Dream doing just fine on the system.
 
RookieBuds

RookieBuds

One of mine is doing that but not as bad, i believe my issue is calcium lockout and/or pH swing. I also do believe 5.75 is on the low side, maybe aim for closer to 6.1 and see if that helps?
 
mysticepipedon

mysticepipedon

40% of your plants is a lot. If almost half don't like how they're being treated, you have to adjust.

I don't use coco, but I believe @RookieBuds is correct, and that pH is a little low.
 
ottomangrows

ottomangrows

3
1
Thanks all. I do appreciate your replies/thoughts.

If anyone else has any other thoughts (beyond PH issue), please do share.
 
extractoilminussixty

extractoilminussixty

  • Little late here in reply, but I am learning as well. My last grow did the same thing I ended up getting a nice harvest with good quality material but the leaves just dried up basically …turns out my ph was low. I spent the money on a digital instant pH reader and it has been worth every penny!
  • Quote-“pH level out of range: Potassium has an optimal pH range between 6.1 and 7.1. If the pH of the soil or water/nutrient solution is above or below that, potassium won’t be available to the plant.”
  • Cont-
  • “Poor soil: Soil that isn’t suitable for cannabis, or is low-quality, will likely be deficient in potassium.
  • Giving too much calcium: Too much calcium can lock out potassium and magnesium.
  • Not providing adequate amounts of nutrients: Not all cannabis strains have the same nutrient requirements. A feeding regimen that works for one cannabis variety may not provide enough nutrients for another.”
Not certain if that’s your problem, but sure looks a lot like it.
I’m now using pH up and down as well as more potassium & phosphorus nuits
(I really have a hard time telling the difference between the two deficiencies)
  • 1625664647613.png


  • 1625664694278.png

1625664775651.png



Below is Phosphorus deficiency—
Plants that are deficient in Phosphorus will look abnormal [leaves will be abnormally shaped] with possible discoloration.

The-Macro-Nutrients.jpeg
 
extractoilminussixty

extractoilminussixty

You know, after going back and looking at your original posted northern lights pictures, I’d have to say that’s definitely phosphorus deficiency !
 
extractoilminussixty

extractoilminussixty

Bloomspect 300 Led
Bloomspect 600 Led
Viperspectra 300 Led
all draw about 130 w - 150w each

Nothing great, but have 7 so figured I’d run them through their life they seem to work fine for me
Much better led lights out there obviously
 

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