Potassium deficiency? Soil grow, White Widow from seed, Sept 2020

OrganiKz said:
How can you not ph your feed. Its instant problems if you give them some hot feed. You gotta know your waters ph and what it is when your feed is mixed in.
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If you are running a hydro or passive hydro type system then yes you need to pH your nutes. When using a product such as Fox Farm soils or Promix soilless media then there is no need to pH your nutes. Buffers such as lime and humus are added into those products which buffer to the correct level every time.
If you run ferts that are high in nitrate than you may find a pH rise in the media over time, but if your N ratio is pretty even between nitrate and ammoniacal then you'll most likely never encounter a problem. As mentioned above the alkalinity of your water will change the pH over time as well. The higher the alkalinity the faster the rise.
Keep in mind that the pH in the medium is what's important, not the pH in the nuted solution.
 
MrSauga said:
If you are running a hydro or passive hydro type system then yes you need to pH your nutes. When using a product such as Fox Farm soils or Promix soilless media then there is no need to pH your nutes. Buffers such as lime and humus are added into those products which buffer to the correct level every time.
If you run ferts that are high in nitrate than you may find a pH rise in the media over time, but if your N ratio is pretty even between nitrate and ammoniacal then you'll most likely never encounter a problem. As mentioned above the alkalinity of your water will change the pH over time as well. The higher the alkalinity the faster the rise.
Keep in mind that the pH in the medium is what's important, not the pH in the nuted solution.
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Makes sense. Yes I agree its definitely the ph of the medium that matters.
 
Really appreciate all the info; I am personally adjusting the ph of my nutes to within the recommended range however; I will read up on ph requirements for buffered soil. Being new, it just ‘appears’ to make sense to offer consistent ph levels but, I am always open to blowing my mind with knowledge... and really good weed !
 
Emeraldo said:
A potassium deficiency does look different. Bright yellow areas bordered by crisp dry brown edges would look like a potassium deficiency. Check this out How to fix Cannabis Potassium Deficiency (K) Pics & Symptoms

This summer, several of my plants looked like the photo of K-deficiency there, only it was mainly caused by a heat wave. I strongly suspected K-deficiency because of how it looked, but concluded it was not. Apparently, intense heat (above 100 F, 38 C) can cause a lockout that looks and feels like K-deficiency, even if there is sufficient K in the soil. The leaf markings went away as respects new leaf growth, but the damaged leaves did not recover. Here's a thread I started on this topic. Potassium deficiency? Or heat stress? Or soil pH too high?

A phosphorus deficiency also differs from your leaves (you have lighter splotches). How to fix Cannabis Phosphorus Deficiency (P) Pics & Symptoms

I think your first step would be to check your soil pH to see if it is in the right range before amending your soil. Soil pH fluctuations can also give rise to splotches not unlike yours. Cannabis pH Management - How to adjust pH in Water and Soil But contrary to conventional grow wisdom, you needn't pH your water -- if soil pH is in the right range, you're good.

Good luck and please post your further findings, like soil pH.
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I had given a thorough watering 5 days ago and again today with approx 10% run off, I sampled the water and they all read between 6.2-6.5PH

all looking good except for a potential inch worm
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really appreciate your help @Emeraldo!
 
Dadbod said:
Really appreciate all the info; I am personally adjusting the ph of my nutes to within the recommended range however; I will read up on ph requirements for buffered soil. Being new, it just ‘appears’ to make sense to offer consistent ph levels but, I am always open to blowing my mind with knowledge... and really good weed !
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Dadbod, it certainly does not hurt to pH your water or nutrient solution. It's just that, after all these years of doing all that work every watering, blindly following what cannabis "gurus" were saying, it turns out that it is pretty established soil science that soil pH is all that matters: if soil pH is good (between 6.0 and 7.0), then your water can be off, say at 7.5, and it will not make any difference. That was welcome news to me, a real game changer. Live and learn... Cheers
 
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