5.8 PH for Hydro/6.5 for soil- Why?

Jimdamick

Jimdamick

Well-Known Member
Always been taught 5.8 is the sweet spot if you use water, but 6.2-6.5 PH for dirt. Why, seeing as the most balanced uptake for all nutes and minerals, at least for Cannabis, is actually 6.0-6.1 I'm confused, so please enlighten me. I'll bet no one knows, and that's why all my food is at 6.0, because I'm a dickhead (no surprise for anyone that knows me)

+REP for good reasons.
 
Last edited:
hotrodharley

hotrodharley

Well-Known Member
Because at a pH of 6.0 in soil or hydro the uptake of Phosphorous, Calcium and Magnesium are almost nil. But you ARE the expert so who am I to argue? You need to revise all the charts the greenhouses are using. Straighten them out.
 
A

AlaskanAutoGrower420

Well-Known Member
hotrodharley said:
Because at a pH of 6.0 in soil or hydro the uptake of Phosphorous, Calcium and Magnesium are almost nil. But you ARE the expert so who am I to argue? You need to revise all the charts the greenhouses are using. Straighten them out.
Click to expand...
You're basically right, except you forgot manganese and iron and potassium when growing in soil, aka organically, because those require a ph between 6.2-6.8, for soilless, its required at 5.8, other professional growers call it "hydro" too because its not soil and there's no nutrients already available in the medium, like hydroponic grows, but this comes to be an argument over time. Im no expert. Just kind of informed on the topic when people ask me what's the difference between them all.
 
hotrodharley

hotrodharley

Well-Known Member
AlaskanAutoGrower420 said:
You're basically right, except you forgot manganese and iron and potassium when growing in soil, aka organically, because those require a ph between 6.2-6.8, for soilless, its required at 5.8, other professional growers call it "hydro" too because its not soil and there's no nutrients already available in the medium, like hydroponic grows, but this comes to be an argument over time. Im no expert. Just kind of informed on the topic when people ask me what's the difference between them all.
Click to expand...
OK so now tell us how to create and maintain 2 different pH levels in one container.
 
boilingoil

boilingoil

Well-Known Member
First off peat products have a pH of 4.9 hence the addition of lime to stabilize the pH.
Second is pure water has a pH of 7.
Third is as your plants use up their nutrients The pH will rise from the exchange of hydrogen atoms.
 
Dr. Who

Dr. Who

Well-Known Member
boilingoil said:
First off peat products have a pH of 4.9 hence the addition of lime to stabilize the pH.
Second is pure water has a pH of 7.
Third is as your plants use up their nutrients The pH will rise from the exchange of hydrogen atoms.
Click to expand...
For some strains in my water only I try and have my pH at 6.7 as they get fussy about Mg uptake if the soil drops and stays lower then 6.5.....
When I have heavy feeders and supplement with a liquid organic mix I blend for the purpose. I always ph it to 6.7 because it starts out to low and drops the soil by at least a point when you water with it.....more so if it's too low.

Keep in mind Jim that soils will drop in pH about that point of pH value and as the soil dries back out it raises back up again. As the above post alludes to. With that in mind, starting a bit higher is good.
The biggest problem I get in Organic soil growing has been pH going low and blocking or restricting P, Ca and Mg uptake! (always seem to see Mg first and all of them together if during bloom if you don't amend the soil right)
For the most part , yeah soil self pH's! BUT, it's what you build the soil with and how you amend for pH stability that REALLY matters over the course of a water only organic run...

Doc
 
Rrog

Rrog

Well-Known Member
Build a natural soil with an eye toward pH neutrality. If you let the system operate, the pH will be shifted by the plant / microbe symbiosis to the pH it wants.

If you're adding bottled nutes, that's not natural, and so you very well may need to adjust pH as you go. I'm not familiar with bottle feeding grows
 
T

THE KONASSURE

Well-Known Member
I ph my hydro down to 5.2 as my max low point and will let it go up to 6.2 as a max then I`d drop it down

I find that higher ph increases my chances of getting root rot in hydro

some where between 5.2 and 6.2 each plant seems to have a sweet spot, the extra pk in flower seems to drop the ph a bit too

As for soil I buy coco or soil or fytocell so don`t normally have ph issues but I always check the water source at the start and set up a feed that`ll keep it nice but most tap water/ bottled water is normally a good ph for soil

but yeah I find ph`ing is just as handy for stopping root rot as it is for helping uptake
 
Keighan

Keighan

Well-Known Member
bongsmilie I would assume in searching for the most suitable ph for the absorption and use of macro and micro nutrients in cannabis there would have to be strenuous tests testing the exact soil composition and how they displace electrons and bond given certain conditions. Given the same could be assumed in hydro from how the photons affect your reservoir, if there are other elements in your water, possible leeching from plastic or pumps, etc. But I'm with hotrod on this one, think it's just a general theory(consensus) that somewheres between 6.2-6.8 has best absorption for micros and macros in soil and 5.5-6 for hydro. IMO.
 
Dr. Who

Dr. Who

Well-Known Member
THE KONASSURE said:
I ph my hydro down to 5.2 as my max low point and will let it go up to 6.2 as a max then I`d drop it down

I find that higher ph increases my chances of getting root rot in hydro

some where between 5.2 and 6.2 each plant seems to have a sweet spot, the extra pk in flower seems to drop the ph a bit too

As for soil I buy coco or soil or fytocell so don`t normally have ph issues but I always check the water source at the start and set up a feed that`ll keep it nice but most tap water/ bottled water is normally a good ph for soil

but yeah I find ph`ing is just as handy for stopping root rot as it is for helping uptake
Click to expand...
Interesting conclusion. I always found it was high res temps that started rot problems....
Ebb or DWC, I always keyed to 5.8 to 6.2 as my limits.......Start at 5.8 and adjust it down every day at lights on......If my pH dropped and not rose...root problems starting!

There were strains that liked it a bit lower but, in the end. I didn't end up caring for those strains - Hydro or soil.....go figure.
 
swiftkillpapa

swiftkillpapa

Well-Known Member
From what I've learned in my SOILS class, meaning I can only speak from knowledge on what goes on in soil. The pH is potential hydrogen. So its a chemistry question. The higher the pH elements like iron get bonded to other elements and can't break down into compounds the roots can uptake. pH is too low things like phosphorus can't become soluble and can't get uptaken by the roots. pH refers to the acidity and alkalinity. 6 pH is 100 fold more then a pH of 5. As 7ph is 100× a pH of 6 and so on. So if something needs more hydrogen ions (acidic) to convert its chemical components such as ammonium phosphate to a useable ammonium nitrate and phosphate but the pH is too high then neither get changed and roots can't break the bond thus rendering it ineffective as a fertilizer. The pH is what allows for fertilizer salts to be broken I to simple compounds roots can use.
Note this is also overlooks microorganism because were talking purely salt based fertilizers.
 
Dr. Who

Dr. Who

Well-Known Member
swiftkillpapa said:
From what I've learned in my SOILS class, meaning I can only speak from knowledge on what goes on in soil. The pH is potential hydrogen. So its a chemistry question. The higher the pH elements like iron get bonded to other elements and can't break down into compounds the roots can uptake. pH is too low things like phosphorus can't become soluble and can't get uptaken by the roots. pH refers to the acidity and alkalinity. 6 pH is 100 fold more then a pH of 5. As 7ph is 100× a pH of 6 and so on. So if something needs more hydrogen ions (acidic) to convert its chemical components such as ammonium phosphate to a useable ammonium nitrate and phosphate but the pH is too high then neither get changed and roots can't break the bond thus rendering it ineffective as a fertilizer. The pH is what allows for fertilizer salts to be broken I to simple compounds roots can use.
Note this is also overlooks microorganism because were talking purely salt based fertilizers.
Click to expand...
So out comes someone with the science end.....Nice - To bad a lot of that will be lost on many here........sometimes that frustrates the hell out of me......whatever..

SO, with what you said....I think you should have mentioned the natural "swing" in pH when soil gets wet/watered....This is how nature makes available the whole nutrient spectrum. Of course again that correlates to the plant and the soil coming to pH "harmony" or symbiotic relation with each other.

Liquid organic nutrition has been, for the most part, a very low pH value when mixed - adjustment is needed or you get the low pH problems from out of range swings that result in the Mg, Ca and P problems I mentioned earlier.

Anyway, I liked your post! I hope someone learns from it!!!!

Doc
 
You must log in or register to reply here.
Top