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Do we need to pH adjust our nutrient solutions?

MrSauga

Photo of the Month: Sept 2018 - Member of the Month: Feb 2019

InTheShed

Member of the Year: 2018 - Member of the Month: Jan 2018, Nov 2018 - Grow Journal of the Month: Aug 2018 - Plant of the Month: Oct 2018

Amy Gardner

Member of the Month: March 2018 - Photo of the Month: April, Dec 2018, Apr 2019
Thanks. I was curious and I guess I need to read up about about the differences of ammonium or nitrate based to understand a little more what is going on.
I know I’ve read that the different forms do different things and both are required, for all plants, not sure in what ratio it at what time tho.

:Namaste:
 

Amy Gardner

Member of the Month: March 2018 - Photo of the Month: April, Dec 2018, Apr 2019
I'm sure it's different from species to species as well.
I’m sure that’s right :thumb:


Thanks Amy..that's a step in the right direction for me as I didn't even know both played a part. I assumed most nute manufacturers used one method (if that's the correct term) or the other.
I’m not sure they have to both play a part, but I know they can (so maybe I shouldn’t have said ‘required’ earlier). One is more readily available and the other requires certain things in place for availability but is then much more efficient for the plants’ purposes. I can’t remember which is which tho. I think it’s the nitrate form that is the less easily available one that is more efficient - but don’t quote me on that.:4:
 
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FelipeBlu

Well-Known Member
We had discussions on the correct way to check the pH of soil or soil-less medium (none involved checking our nute runoff:)). I'll post the various methods he sent me in a different thread and post a link here. I don't want to distract from the info above!
Are we ready now?
 

farside05

Plant of the Month: Dec 2018, June 2019
I think it would be difficult to formulate given the variation in water alkalinity, as well as differences in substrates when they are making nutes for coco/hydro/soil/soil-less. I mean MegaCrop can't even figure out which NPK formula they want to go with (three different ratios over the last three months!).
I believe that the company that makes MSU Orchid Fertilizer will custom blend fertilizers based on medium and water samples you provide them, but that's for like big green house type volume of fertilizer.
 

Amy Gardner

Member of the Month: March 2018 - Photo of the Month: April, Dec 2018, Apr 2019
Oh, and for some reason I had work today!
Outrageous!
I believe that the company that makes MSU Orchid Fertilizer will custom blend fertilizers based on medium and water samples you provide them, but that's for like big green house type volume of fertilizer.
Interesting! :thumb: high-Brix hobby gardening is the same in that it’s taking a system of principles and measurements designed for large scale agriculture and applying it to hobby growing. That could surely be done with this company. Take a lot of R&D to work out what the balance needs to be at each stage of a cannabis grow... but it’s not impossible. The general science is already there :Namaste:
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
Greetings all!
How ya doin', lol? I'm going to do something I rarely do and post a reply after reading ONLY the first post (it's late and if I start thinking, I'll be up all night ;) ) - but I'll read the remainder of the thread in the next day or three, when I get time.

What you posted in post #1 - insofar as (I think) I understand it - agrees with other things that I have read (insofar as I think I understood them). I think everyone has heard or read something like "soil has buffers."

"It is the potential acidity or basicity of the fertilizer chemistry and the alkalinity content of your water that affects the pH of the growing medium. For the fertilizers, it is called ‘potential’ since it is determined by the chemistry and the quantity of fertilizer nutrients that are applied and the ‘potential’ they have to interact with the plant root system and influence the pH of the growing medium up or down."

All related to the medium. And the interesting use of the word "potential," but again ended it by talking about moving the pH of the growing medium.
Yeah, municipal water quality reports (everyone who pays a water bill should get one of these once a year or so) sometimes mention this. They don't always mention pH ;) .

1. Ideal pH range for mineral soil is 6.0-6.5. Soil-less growing media, such as PRO-MIX, have an ideal pH range of 5.5-6.0.
I knew that stuff was closer to a hydroponic media than it was to actual soil, lol. Well, some of it. Turns out they have a range of products, and some seem to be... closer to soil than others. (If I'm not mistaken - which is certainly a possibility here.)

2. However, pH of nutrient water is irrelevant to the pH of any soil or growing media. It is the alkalinity of nutrient water and the potential acidity/basicity of the fertilizer(s) that influence the pH of the growing medium and root zone. For example, if the alkalinity of nutrient water is moderate or high, pH of growing medium will rise over time.
At that point, did you find yourself thinking, "But alkaline water has a high pH...?"

Some of this stuff appears to be counterintuitive . At least it does to me. Especially when it's past my bedtime.

a. Plant roots are electrically charged and must maintain a neutral balance.
Who was it that did the "electroshock therapy" plant experiment a while back, Emilya? I wonder if any positive results that she might have experienced could have been chalked up to the process helping out a plant that happened to be in a less than perfect environment? (NOTE: A less than perfect environment... can still be pretty good; I am not trying to infer that it was bad.)

And at the bottom of that summary I added one last direct question:

"If I’m growing in ProMix HP and I mix up the nutrient solution and it reads 7.4 pH, it is not necessary for me to adjust that number down using phosphoric acid or the like. I can pour it into the pot at 7.4 and my plants will be able to uptake those nutrients?"

His response was a direct "Yes."
Well, a lawyer might, if you asked him, "Is it necessary to put a coat on before venturing outside when it's below 32°F?" say, "No." After all, lol, you wouldn't have been asking if it is a good idea to do so, or whether you might eventually regret not doing so.

I don't know if that's the same mindset that he answered your question from, though. We add lime to soil if that soil is too acidic (for example), but I don't know if we then proceed to add (in the process of feeding / watering) stuff that has a (too) low pH for the next several weeks... if we are, by doing so, "using up that lime." I'm just way too ignorant to know one way or the other, as you can no doubt tell by the general wording of this post. I have grown in soil(ish) before, but I don't consider myself to be a "soil guy." Which is ironic, because I've been in a bit of a panic trying to buy some without having to call Guido the Knife's boss for one of his "special" loans :rolleyes: ; I saw that Amazon had "FREE" shipping through the end of the month, so I hit their website to buy a 2 cubic foot bag of Fox Farm Happy Frog - and noticed that all their $13.50 bags are now suddenly $39.95 "for some reason." #@%&ing fraudsters, lol, that's like when a local grocery store (since gone out of business) used to jack the prices on its "sale" items (and quite a few other items, too) 25% immediately before their "10% off" sale circular showed up in the Sunday paper. But I digress.

We had discussions on the correct way to check the pH of soil or soil-less medium (none involved checking our nute runoff:)).
Did he happen to use the words "slurry test," lol? Because that's how I've always heard ( / read / stated / typed) one should test the pH of a soil(ish) substrate.

Interesting topic, and thank you for posting this thread. BtW, there was an article about pH, ions, et cetera some time ago in that advertisement that Advanced Nutrients publishes. I think the publication is called Maximum Yield. I don't remember the title of the article, but it has also been published on the Internet, so I've probably got it bookmarked. If I don't forget, I'll try to hunt it up when I return to properly read this thread. It might be an aid in understanding some of this stuff (or it might not, lol, since I cannot swear that I am correctly remembering what it was about).
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
Okay, I lied - I read the second post, too.

Hmmm, I wont argue, but who's gonna be the guinea pig? 7.4 seems high to me.
All the countless growers who never bothered to check the pH of anything throughout the history of growing cannabis and still managed to get a harvest from their efforts?:19:
 

FelipeBlu

Well-Known Member
From the source provided by Farside:

“The primary problem associated with low alkalinity water is a tendency for substrate-pH to drop over time, which can cause micronutrient toxicity problems. Usually, low pH problems are a result of fertilizer selection. Fertilizers high in ammoniacal nitrogen are acidic, and without any alkalinity in the water to balance the reaction (resist lowering of pH), acidic fertilizers will tend to drive the substrate-pH down over time.”
 

farside05

Plant of the Month: Dec 2018, June 2019
From the source provided by Farside:

“The primary problem associated with low alkalinity water is a tendency for substrate-pH to drop over time, which can cause micronutrient toxicity problems. Usually, low pH problems are a result of fertilizer selection. Fertilizers high in ammoniacal nitrogen are acidic, and without any alkalinity in the water to balance the reaction (resist lowering of pH), acidic fertilizers will tend to drive the substrate-pH down over time.”
When I was researching this topic heavily about a year ago, I noticed a lot of nute companies seem to balance the amout of Ammoniacal Nitrogen (drives pH down) with Nitrate Nitrogen (drives pH up) in a 1:3 ratio. It's probably not a coincidence that ratio seems to occur often, across several companies.
 
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