High pH expanded clay

[Maggie Culver]

Someone on here suggested that my media might be the culprit causing my high pH, so I tested some expanded clay from my beds and some that had never been used.  I put water in with each and waited a couple of hours and tested the water.  I also tested my well water for comparison.  My well water is pretty neutral.  The clay water in both cases was definitely more alkaline.  Isn't it a little odd for this to be the case?  I'm not sure what to do about it (other than I am having water run through some peat moss in cheesecloth to see if it will help lower the pH).  Any advice?

[Vlad Jovanovic]

Hi Maggie...take your well water and let it sit out in a glass for about 3 days...then test the pH and see what it says.

Your well water may in all likelihood actually have a significantly higher pH than you are being led to think, if you are testing it right out of the tap without letting it sit out first for a few days to off-gas the carbon dioxide. 

Carbon dioxide is only water soluble when pressure is maintained (like in your water pipes). In this dissolved state it is called carbonic acid (H2CO3). Since it is a weak acid, when you measure water right from the tap without letting it sit out for a day or so, it will give you a false low pH reading. Once the the carbonic acid has a chance to off-gas into CO2, and escape into the air, you can only then measure the pH of your water and confidently obtain a realistic reading. The difference can pretty big too. (something along the lines of one half to one and a half pH points..This is a simplified description of that relation:

 

CO2 + H2O --> H2CO3

After that the carbonic acid reacts slightly (and reversibly) in the water to form a hydronium cation H3O-+ and the bicarbonate ion HCO3-

H2CO3 + H2O --> HCO3- + H3O+

[Rob Nash]

I have heard of some clay having a sulfur smell and keeping the pH too low.. but it seams odd to keep it high..

my advice is the same as always ,.. leave the pH high for now.. it will kick start your system faster, and the pH will drop on its own later.. dont sweat it!  add some stuff like greensand, actino iron, and my personal favorite "Minerals Plus"(it has every supplement your plants will ever need, ) to your media... the Actino Iron will uptake even with the high pH.

[Maggie Culver]

Will do.  Thanks!   What about testing my clay? 

Vlad Jovanovic said:

Hi Maggie...take your well water and let it sit out in a glass for about 3 days...then test the pH and see what it says.

Your well water may in all likelihood actually have a significantly higher pH than you are being led to think, if you are testing it right out of the tap without letting it sit out first for a few days to off-gas the carbon dioxide. 

Carbon dioxide is only water soluble when pressure is maintained (like in your water pipes). In this dissolved state it is called carbonic acid (H2CO3). Since it is a weak acid, when you measure water right from the tap without letting it sit out for a day or so, it will give you a false low pH reading. Once the the carbonic acid has a chance to off-gas into CO2, and escape into the air, you can only then measure the pH of your water and confidently obtain a realistic reading. The difference can pretty big too. (something along the lines of one half to one and a half pH points..This is a simplified description of that relation:

 

CO2 + H2O --> H2CO3

After that the carbonic acid reacts slightly (and reversibly) in the water to form a hydronium cation H3O-+ and the bicarbonate ion HCO3-

H2CO3 + H2O --> HCO3- + H3O+

[Maggie Culver]

Rob Nash said:

I have heard of some clay having a sulfur smell and keeping the pH too low.. but it seams odd to keep it high..

my advice is the same as always ,.. leave the pH high for now.. it will kick start your system faster, and the pH will drop on its own later.. dont sweat it!  add some stuff like greensand, actino iron, and my personal favorite "Minerals Plus"(it has every supplement your plants will ever need, ) to your media... the Actino Iron will uptake even with the high pH.

My system is actually more than 2.5 years old.  I would have thought it should have been more acidic by now.  I will try some of those minerals.  Thank you!

[Scott Roberts]

What makes you say the action iron would uptake even with high pH? It's not synthetically chelated....

Rob Nash said:

I have heard of some clay having a sulfur smell and keeping the pH too low.. but it seams odd to keep it high..

my advice is the same as always ,.. leave the pH high for now.. it will kick start your system faster, and the pH will drop on its own later.. dont sweat it!  add some stuff like greensand, actino iron, and my personal favorite "Minerals Plus"(it has every supplement your plants will ever need, ) to your media... the Actino Iron will uptake even with the high pH.

[Rob Nash]

not sure why,, but it does its biological magic at high pH ranges... Green sand works at high pH too.

perhaps its because the higher pH is good for bacterial growth etc, thus the Streptomyces Lydicus WYEC 108 and 47% humic acid, can work at higher pH.,  it takes a while for it to get established, but it does a great job.. i add it in the hole of every plant i put in the media beds and it does the job for the life of the plant.

[Vlad Jovanovic]

Hi Scott...there are many, many non-synthetic ligands (or other structures) with which to chelate a metal ion...I got to do a presentation for Sylvia's team about this last winter...

In nature, competition between microbes can be fierce, and Iron is often a limiting factor. So microbes have developed mechanisms (siderophores) by which to "grab and hold onto" (chelate) and assimilate (and often redox) Fe. Some of he siderophores I've been using are called bacillibactin...Novozyme, the company for whom Natural Industries distributes for, use a desferioxamine to complex their Fe in Actino-Iron.

At present time, there are well over 500 known siderophores, humans have been able to determine the chemical structures of only about 270 of them. There are likely many more than 500 types. The reason there are so many and that they are not "interchangeable" is probably so that the microbes don't end up playing 'evolutionary kill the carrier' (the ball being the Fe ion) and just keep stripping and swiping each others iron...anywho's...

I'm only concerned with siderophores that have been developed by microbes in aerobic conditions where iron comes in the form of Fe3+, is only sparingly soluble, and is often the limiting factor of growth in both plants and microbes. Those are the ones that should interest folks with green thumbs (even wet green thumbs that smell like fish)...

As I'm sure you probably know Scott, ferric iron (Fe3+) is a hard Lewis acid...and being one, it naturally prefers a hard Lewis base. Something like anionic oxygen, a 'material' microbes have learned to 'construct' with to their advantage.

After nabbing the Fe3+ with the pincer-like-Lewis-base-siderophore, they then (usually) redox and release the iron as Fe2+ (since the ferrous iron has no such affinity for the above described ligand). So just because it isn't "synthetically chelated" doesn't mean it wont work at high-ish pH ranges :) Just how well it will work and what those upper limit ranges are though is anybody's guess. But Rob is certainly onto something by applying it locally (in the hole of every plant) as opposed to dispersing it in into his system as you would want the Streptomyces (with their siderophores) to colonize the roots

*(The above only describes the siderophore that I'm familiar with [part of a family called Catecholates]...NOT Actino-Irons [desferioxamines])

[Maggie Culver]

I found the Actino Iron but I can't find "Minerals Plus".  Where might I find it?

Rob Nash said:

I have heard of some clay having a sulfur smell and keeping the pH too low.. but it seams odd to keep it high..

my advice is the same as always ,.. leave the pH high for now.. it will kick start your system faster, and the pH will drop on its own later.. dont sweat it!  add some stuff like greensand, actino iron, and my personal favorite "Minerals Plus"(it has every supplement your plants will ever need, ) to your media... the Actino Iron will uptake even with the high pH.

[Maggie Culver]

Vlad,  You were right!  After a day and a half, I tested it and it is already pretty alkaline.  What do I do now?  I have ordered the Actino Iron and some Excelerite minerals (can't find the "Minerals Plus") so I'll at least try to get that going.  I have read about using rain water and RO water but the RO would be a bit cost prohibitive even if I could figure out how to do it in my greenhouse.

Maggie Culver said:

Will do.  Thanks!   What about testing my clay? 

Vlad Jovanovic said:

Hi Maggie...take your well water and let it sit out in a glass for about 3 days...then test the pH and see what it says.

Your well water may in all likelihood actually have a significantly higher pH than you are being led to think, if you are testing it right out of the tap without letting it sit out first for a few days to off-gas the carbon dioxide. 

Carbon dioxide is only water soluble when pressure is maintained (like in your water pipes). In this dissolved state it is called carbonic acid (H2CO3). Since it is a weak acid, when you measure water right from the tap without letting it sit out for a day or so, it will give you a false low pH reading. Once the the carbonic acid has a chance to off-gas into CO2, and escape into the air, you can only then measure the pH of your water and confidently obtain a realistic reading. The difference can pretty big too. (something along the lines of one half to one and a half pH points..This is a simplified description of that relation:

 

CO2 + H2O --> H2CO3

After that the carbonic acid reacts slightly (and reversibly) in the water to form a hydronium cation H3O-+ and the bicarbonate ion HCO3-

H2CO3 + H2O --> HCO3- + H3O+

[Rob Nash]

minerals plus should be available online... try amazon

follow the directions on the bag... i did something like 4lbs / 100 sft.

[Scott Roberts]

Vlad - thanks for clearing that up! You're a font of knowledge. I look forward to meeting you in a couple weeks at the AquaponicsFest.

Vlad Jovanovic said:

Hi Scott...there are many, many non-synthetic ligands (or other structures) with which to chelate a metal ion...I got to do a presentation for Sylvia's team about this last winter...

In nature, competition between microbes can be fierce, and Iron is often a limiting factor. So microbes have developed mechanisms (siderophores) by which to "grab and hold onto" (chelate) and assimilate (and often redox) Fe. Some of he siderophores I've been using are called bacillibactin...Novozyme, the company for whom Natural Industries distributes for, use a desferioxamine to complex their Fe in Actino-Iron.

At present time, there are well over 500 known siderophores, humans have been able to determine the chemical structures of only about 270 of them. There are likely many more than 500 types. The reason there are so many and that they are not "interchangeable" is probably so that the microbes don't end up playing 'evolutionary kill the carrier' (the ball being the Fe ion) and just keep stripping and swiping each others iron...anywho's...

I'm only concerned with siderophores that have been developed by microbes in aerobic conditions where iron comes in the form of Fe3+, is only sparingly soluble, and is often the limiting factor of growth in both plants and microbes. Those are the ones that should interest folks with green thumbs (even wet green thumbs that smell like fish)...

As I'm sure you probably know Scott, ferric iron (Fe3+) is a hard Lewis acid...and being one, it naturally prefers a hard Lewis base. Something like anionic oxygen, a 'material' microbes have learned to 'construct' with to their advantage.

After nabbing the Fe3+ with the pincer-like-Lewis-base-siderophore, they then (usually) redox and release the iron as Fe2+ (since the ferrous iron has no such affinity for the above described ligand). So just because it isn't "synthetically chelated" doesn't mean it wont work at high-ish pH ranges :) Just how well it will work and what those upper limit ranges are though is anybody's guess. But Rob is certainly onto something by applying it locally (in the hole of every plant) as opposed to dispersing it in into his system as you would want the Streptomyces (with their siderophores) to colonize the roots

*(The above only describes the siderophore that I'm familiar with [part of a family called Catecholates]...NOT Actino-Irons [desferioxamines])

[Maggie Culver]

Thank you to all of you for your help!  I feel like such a "dummy" for not even knowing my water was so alkaline!  But I guess I'm in a better position to help others in the future having gone through this.  I will feed my plants with the Acto Iron and Minerals Plus, and I will use the muratic acid to lower my pH.  Hopefully, with time, maybe my system will naturally lower the pH on it's own. 

Again, thanks!