How do I raise pH of soil while growing one?

[Fweed]

I got my ph tester after making soil and forgot to test it!

I've been growing for 2 weeks and my plant seem seek so I tested all the things and it hit me that I didn't test the soil and I tested.

Sadly it was 4.5.

Should I buy lime and mix another batch and replace it? or can I raise it by giving water with higher ph??

 

[Bush Doctor 77]

Hard water with Ca in it will help raise the pH. Be careful with lime. You can buy "pH UP" liquids for you nutes, too.

 

[bobrown14]

How did you test the soil pH?

 

[Emilya Green]

if your soil was actually down in the 4's your plants would have already burst into flames. It is not possible to grow in soil that acidic... so, I suspect that you really don't know what your soil pH is. So, is this a commercial soil or stuff out of your yard? If it is a commercial soil its pH is probably fine for growing cannabis...
If you try to adjust your soil by sending in fluids drastically the opposite, you will also blow up your plants. Let's just back up a bit and test some of your assumptions. Give us some more details, please.

 

[Fweed]

Thanks guys.

Here's some details.

How to Test Soil pH

This is how I tested soil ph. Mix soil with distilled water.
Distilled water was around 6.5 before mix, and mix was 4.5.

I mixed soil by myself with commercial stuff.
I searched soils for autoflower, and found out recipe below.

3 parts compost.
3 parts peat moss.
2 parts wet perlite.
1 part wet vermiculite.
(The Definitive Guide To The Best Soils For Cannabis)

Bought it separately and mixed.

Plant is 17 days old.
Watered with Dyna-gro nutrients(Pro-tekt, Foliage, mag-pro).
Always set ph to 6.5 using apple vinegar.

I'm first time grower, with only one plant for learning and to get feminized pollen.
I'll appreciate your help!

 

[Emilya Green]

Thanks guy.

Here's some details.

How to Test Soil pH

This is how I tested soil ph. Mix soil with distilled water.
Distilled water was around 6.5 before mix, and mix was 4.5.

I mixed soil by myself with commercial stuff.
I searched soils for autoflower, and found out recipe below.

3 parts compost.
3 parts peat moss.
2 parts wet perlite.
1 part wet vermiculite.
(The Definitive Guide To The Best Soils For Cannabis)

Bought it separately and mixed.

Plant is 17 days old.
Watered with Dyna-gro nutrients(Pro-tekt, Foliage, mag-pro).
Always set ph to 6.5 using apple vinegar.

I'm first time grower, with only one plant for learning.
I'll appreciate your help!

a couple of observations:
distilled water has to be 7.0 pH unless it has set out in the open for quite a while and absorbed a lot of co2. Then looking at the method they describe to measure soil pH, not stressing an equal weight of distilled water and soil, I suspect the accuracy of that test so I question the accuracy of your pH measurements and think that your mix must be in the 5s somewhere.
Since you went with the autoflower mix and not the supersoil mix, you should suspect that your adjusting the pH into the soil range might not be correct. I would contact the folks over there that recommended this recipe and see what pH they adjust to... I am suspecting 6.1 to be what they shoot for and then the acidic mix will drift the pH downwards thru the hydro range. Chalk this up to being just another one of the many different ways to grow this weed.

 

[bobrown14]

Yeah that's not how soil is tested for pH! Pretty 420% on that.

We have laboratories at all the state universities that do this testing. It's call the "county extension service". Novel idea really and its been a thing since about 1930.

Predating that name sake for that corporation the "expert" is working for.

Winrock - "Inspired by its namesake Winthrop Rockefeller "

I'm sure they are doing good work somewhere I hope.

What is a "Food Systems Expert" anyways??

He's teaching children this stuff. Be better working on the soil food web or something more important than soil pH.

Please people when you read stuff it doesn't make it true. Trust and verify.

Digging a hole in a field and pouring water in it to test soil pH? Really?

Thats just plain silly.

Yeah thats not a test. Its just pouring water in a hole. Be better off planting a tree along with. For sure.

 

[Emeraldo]

...I've been growing for 2 weeks and my plant seem seek so I tested all the things and it hit me that I didn't test the soil and I tested.

Sadly it was 4.5.

Should I buy lime and mix another batch and replace it? or can I raise it by giving water with higher ph??

...This is how I tested soil ph. Mix soil with distilled water.
Distilled water was around 6.5 before mix, and mix was 4.5.

I mixed soil by myself with commercial stuff.
I searched soils for autoflower, and found out recipe below.

3 parts compost.
3 parts peat moss.
2 parts wet perlite.
1 part wet vermiculite.
(The Definitive Guide To The Best Soils For Cannabis)

Bought it separately and mixed.

Plant is 17 days old.
Watered with Dyna-gro nutrients(Pro-tekt, Foliage, mag-pro).
Always set ph to 6.5 using apple vinegar.

I'm first time grower, with only one plant for learning and to get feminized pollen.
I'll appreciate your help!

Fweed, how is your plant doing? You say it seemed "seek", but what symptoms is your plant actually showing? Can you post a photo? It sounds like you saw the low pH reading and concluded that you therefore have a problem. If the reading is false, then you don't know what the problem, if any, is yet.

Also, what amount of soil did you mix? Are you using a 15-gallon pot? or a 5-gallon?

I agree with Emilya that pH 4.5 would be way too acidic and your plant would most likely be dead by now if that were the correct reading. Peat moss is usually quite low, and depending on how much of that you added, that could easily create a soil pH below 5 (I've tested my peat moss and it was 4.5)

You mentioned lime. As I guess you know already, lime tends to bring up the pH of soil towards pH 7.0. If your 15-gallon pot of soil has a low pH, say it's in the 5.5 range somewhere, I would either 1. re-mix your soil with lime (probably 2 cups per 15-gallon pot) or 2. top dress your plant in the pot with lime, mix it into the topsoil, and water. Lime needs watering to become activated, and after a few weeks or so you'll have a higher soil pH.

As you also mentioned, you can adjust your water pH up to compensate for low soil pH. So instead of using water at 6.5 (which is often about right for cannabis), in your "5.5" soil you might use water with a higher pH, say water @ 7.0 or even higher if needed. This will also tend to bring up the pH in the growing environment, better for nutrient absorption. It's not a perfect fix, at best a short-term fix.

Hope this helps

 

[TorturedSoul]

This is how I tested soil ph. Mix soil with distilled water.

I've always done it in a jar, with equal parts soil and distilled water, screwed the lid on, shaken the <BLEEP> out of it, removed the lid, allowed the solids to settle for a bit, and then tested the water.

Distilled water was around 6.5 before mix, and mix was 4.5.

Hmm... Check the calibration on your meter, lol, and recalibrate properly if necessary. If meter allows for two-part calibration, be sure to use both.

By the way, I'm assuming it's a digital pH meter. If it's one of those cheap analog "3-in-1" meters, well... they make good back-scratchers .

I mixed soil by myself with commercial stuff.
I searched soils for autoflower, and found out recipe below.

3 parts compost.
3 parts peat moss.
2 parts wet perlite.
1 part wet vermiculite.

As has been mentioned, peat moss is acidic. Next time, use less of it. Skip the vermiculite, too, IMHO. Your mix will have a higher pH.

Always set ph to 6.5 using apple vinegar.

Personally, I'm not in favor of using vinegar and baking soda as pH adjusters; if you have to adjust the pH of your water and/or nutrient solution, use something that the plant can eat (usefully). Others' opinions might vary, I suppose.

 

[bobrown14]

I herd digging a hole and pouring water in it is a way to test pH. lol

Seriously, pH soil test at home is not that accurate.

Here's a study done by Oregon State University "extension service"

I can get a comprehensive soil test that includes pH test in a soil lab from our local county extension service (all states have an extension service) for $8 includes shipping.

Here's the study - it covers probes, test strips and meters.

A plus minus of 2 points on a pH test is what I wood call in-accurate at best.

So just a little food for thought. Your pH test might not be as accurate as you think it is.

Measuring Soil PH

 

[Dennis922]

I herd digging a hole and pouring water in it is a way to test pH. lol

Seriously, pH soil test at home is not that accurate.

Here's a study done by Oregon State University "extension service"

I can get a comprehensive soil test that includes pH test in a soil lab from our local county extension service (all states have an extension service) for $8 includes shipping.

Here's the study - it covers probes, test strips and meters.

A plus minus of 2 points on a pH test is what I wood call in-accurate at best.

So just a little food for thought. Your pH test might not be as accurate as you think it is.

Measuring Soil PH

A slurry test is actually a pretty accurate way to test soil ph. Google it.

 

[Emilya Green]

A slurry test is actually a pretty accurate way to test soil ph. Google it.

in a vacuum, so that collected co2 doesnt skew the result. A slurry test is not a hole in the ground, it is a scientifically measured equal weight of a representative soil sample, mixed in an equal weight of distilled water. It is an accurate test if done correctly, but only tells you the base pH of that soil, when dry. Until you know why that number is typically adjusted to 6.8 or so, soil can be confusing.

 

[bobrown14]

A slurry test is actually a pretty accurate way to test soil ph. Google it.

I'm well aware of this test you speak of.

The accuracy of this method is well not accurate so why do it?

I think the +/- accuracy is like 4pH either way. Same with a probe.

You need lab equipment and a lab to to an accurate test.

At any rate, soil pH is dynamic, it's not a very important part of a soil test. In a living soil the pH is in constant change. You could measure 5 times and get 5 different readings. Which one is correct??


Measuring things like CEC (cation exchange) is a much better test result to look at. As are the nutrient test results.

 

[TorturedSoul]

in a vacuum, so that collected co2 doesnt skew the result.

I've been wondering about that kind of thing in general. I know that it'll quickly change the result of "0 PPM" distilled water, but that's sort of a special case (if it were me making the decision, I'd have probably set the neutral pH point to be 0 instead of 7, lol). Is it really going to affect a standard slurry test enough to cause problems for the average cannabis grower? Or even the average large-scale food crop farmer? I'm assuming, here, that people don't normally open the container that their distilled water comes in and leave it that way for a week or two before using it.

I'm well aware of this test you speak of.

The accuracy of this method is well not accurate so why do it?

I think the +/- accuracy is like 4pH either way. Same with a probe.

I got the impression that the accuracy was more like ±.2 if done correctly, and possibly better with a more accurate meter (one with an accuracy greater than ±.1). I've also gotten the impression from reading some of the posts by the "organic" soil growers that this would be more than close enough for a soil grower's needs. IDK, really, that's just the impression I've gotten.

The folks at Cole-Parmer Instrument Company, LLC. recommend a slurry test with the usual instructions (dry soil weighed out in grams, equal mass of distilled water in ml, both soil and water at the same temperature, accurate meter, two-part calibration using the correct second calibration solution for the expected pH of the sample), and seem to think it's accurate enough.

But that's just an equipment manufacturer/distributor. While I'd hope that someone at the company has enough sense to know whether or not the pH meter they manufacture, and recommend for this purpose, and the procedure they recommend for this purpose... would be capable of producing valid results, I have no real way of knowing that other than purchasing that meter, using the company's recommended procedure to test multiple samples, then having them retested at a proper lab. And that seems like it'd cost a fair bit of money, so... no.

I know you recently posted an article about such things from a state's extension office. Here's another such article, written by Paul Carter (associate professor, extension agronomist, and precision agriculture specialist, WSU Department of Extension Ag and Natural Resources (ANR)). He seems to think one can get accurate enough results without using the services of a lab. He also mentioned one particular soil pH meter (not one of the cheap 3-in-1 POS things), the ExTech Soil ExStik 110 pH meter. The probe is somewhat different than the digital meters I'm used to using at home, looks like it's flat on the bottom (and possibly larger than the usual ones), I assume for a greater direct contact patch with the soil.

https://pubs.cahnrs.wsu.edu/publications/pubs/fs205e/?p-page=1

I'd like to get a look at one of the sources he listed:

Davenport, J.R. and J.D. Jabro. 2001. Assessment of Hand Held Ion Selective Electrode Technology for Direct Measurement of Soil Chemical Properties. Communications in Soil Science and Plant Analysis, 32(19&20), 3077-3085.

 

[Emeraldo]

A slurry test is actually a pretty accurate way to test soil ph. Google it.

Yes. I agree. I test a slurry of equal parts (a) soil and (b) water with pH of 7.0. Shake and allow to settle. Test the liquid on top. (I use a Hanna Instruments meter.) Result may not be within +/- 0.1, but if the result is less than 7, then I have an indication of acidity. For example, a result of pH of 6.0 would be the combined result of the water (pH 7) and the soil (which we know must be less than 6, possibly around 5.5). Not precise, but imho the slurry test is close enough.

I'm well aware of this test you speak of.

The accuracy of this method is well not accurate so why do it?

I think the +/- accuracy is like 4pH either way. Same with a probe.

Bob, do tell how you arrived at your opinion on the accuracy of the slurry test method. Is it really your information that, for soil with a pH of 7, the slurry test if done properly will produce a result with a deviation of +/- 4? So, to follow that, in any given case the same soil might come out somewhere between 3 and 11? If that were true, the slurry method would tend to cause more harm than good. It just seems to me that you once again have not substantiated the basis for your opinion, with the risk that thousands of innocent 420 newbies will follow you down the primrose path to cannabis doom.

 

[TorturedSoul]

Yeah, come to think of it, since a change of 1 (not .1, but 1) denotes a 10x change in acidity/alkalinity, since it's a logarithmic scale. I expect that you could get within ±4 by tasting the soil.

But I'm not willing to test that hypothesis. There are unleashed dogs in the neighborhood .

 

[bobrown14]

OK slurry test in the field is NOT accurate.

If it was why does every state have a "Extension Service" so that farmers (all sizes) and home gardeners can send in soil to be tested and the pH is part of the test and it's done in the LAB not in the field.

There's reason for that. Emiliya hit on it earlier.

This is not an argument. This is fact and science.

If you don't believe me, thats fine and dandy. Do your pH slurry test from your soil, then send that same soil into your state soil lab and have it tested. Compare and report.

I'm just saying that your slurry test is NOT accurate or your probe result.

pH is a logarithmic, so a reading of 6pH is 10 times more acidic than a reading of 7pH.

Maybe you can get in the ball park maybe not with your slurry test. I'm just saying the slurry test is not accurate.

I depend on my local extension service to do this test for me. I feel pretty good about the result. A soil test is much cheaper than a test probe. My cost is $8 includes everything I need to know about my soil including pH.


As an example of how a slurry test is done and it won't be accurate:

Take tap water with say a pH of 8 and do your slurry and test. That 8pH of your tap water is going to skew your results BIG TIME and give you wrong results. Lets say your now want to lower your soil pH and you adjust accordingly. You going in blind. No way you're able to achieve the result your looking for.

Lab testing removes all variables. Thats my argument.

We are paying for these labs (extension service - soil labs) with tax money. Take advantage of them. It's basically completely paid for all you pay for is shipping - not even really. My cost where I live is $8 for a comprehensive soil test includes soil pH.

So, to follow that, in any given case the same soil might come out somewhere between 3 and 11? If that were true, the slurry method would tend to cause more harm than good. It just seems to me that you once again have not substantiated the basis for your opinion, with the risk that thousands of innocent 420 newbies will follow you down the primrose path to cannabis doom.

Emeraldo - one question, do you "flush" your soil??

What I'm saying is have your soil tested in a LAB - not in your back yard.

Anyone taking that advice won't be going down a path of doom. 420% on that.

 

[TorturedSoul]

This post might be a bit lengthy for a quick glance from a cell phone. Sometimes... you'll have that.

OK slurry test in the field is NOT accurate.

Again, the guy who wrote the article I grabbed (from a state extension office's website) seemed to think it was accurate enough. But maybe he's just some mouth-breather goof that they've got on staff to sweep the floors? Let me check... ... ... Well, I found some information about him - and if he's their janitor, then their personnel requirements are fierce, lol:

(From the Washington State University's Center for Precision and Automated Agricultural Systems website) "Associate Professor... WSU Extension and Columbia County Director... Paul Carter joined WSU Extension in 2005 serving Columbia County Extension Office as Director and Educator. In 2011 he completed affiliate status with CPAAS as a remote sensing and dryland precision agriculture specialist. From Purdue University, he earned his B.S. (1974) in Agriculture Mechanization, M.S. (1999) in Agronomy Soil Science, and completed Ph.D. (2005, all but dissertation) Agronomy Remote Sensing. While completing degrees at Purdue University, he worked as a staff member with the Laboratory for the Applications of Remote Sensing (LARS). Paul’s Extension programs in agriculture include precision technology applications, soil nutrition, and weed management. He participates in many of the state’s agriculture organizations including Sec/Treas of the Washington State Crop Improvement Association. Internationally, he serves on the editorial board of the Journal of Precision Agriculture and presents at international conferences. Paul has initiated local Precision Farming seminars in Columbia County, presented at Lincoln-Adams, Garfield, and Walla Walla counties in Washington and Morrow county in Oregon. His leadership has impacted the adoption of precision technologies in the dryland wheat production area of Washington State."

Nah, probably doesn't have time to sweep and mop after all, what with him being busy running the place and all . But IDK, maybe he is one of those people that manage to insert themselves into organizations and then just coast, not really contributing anything other than drivel and embarrassing staff Christmas party memories. I'll read on and see what I can come up with...

Extension agent honored for soil health support for Washington farmers - October 9, 2018
By Seth Truscott, College of Agricultural, Human, and Natural Resource Sciences

In southeast Washington’s Columbia County, WSU Extension Agent Paul Carter has earned national recognition for his efforts helping farmers preserve the health of their soil.

Carter, director of Columbia County Extension and an Agriculture and Natural Resources agent, received the 2018 Distinguished Service Award from the National Association of County Agricultural Agents (NACAA). This award honors members who have served at least 10 years in cooperative extension, led outstanding Extension programs, and earned the esteem of their colleagues.

Based at Dayton, Wash., Carter works with farmers to balance nutrients in their crop systems, improving soil health and reducing soil acidity. He conducts soil health workshops for farmers and decision makers to prevent soil degradation, leads on-farm demonstrations, organizes seminars, and speaks at local and regional grower meetings.

“Our soils are the basis of life, and soil health determines the quality and health benefits of the foods we grow and eat,” said Carter. “Whether it’s crops for feed, grain or for our own table, by working with producers to improve the soil, we ultimately improve the nutritional value of our diet.”

A productive member of the WSU Wheat and Small Grains Extension Team in Pullman, and affiliate faculty with the Center for Precision and Automated Agricultural Systems in Prosser, Carter has authored several book chapters, curriculum materials, and educational publications on soil health.

“It was a great honor, and a humbling experience, to be selected by my peers here in Washington, and then be recognized at the national annual meeting with many other recipients,” Carter said. “As an Extension agent, I help in any capacity that I can for the benefit of my stakeholders and the community.”

https://cpaas.wsu.edu/our_people/paul-g-carter/

Extension agent honored for soil health support for Washington farmers

WSU Extension Agent Paul Carter has earned the 2018 Distinguished Service Award from the National Association of County Agricultural Agents.

news.wsu.edu

Fawk, IDK, man, I'm with you on this one - we shouldn't believe anything this clown says or writes.[/SARCASM ]

If it was why does every state have a "Extension Service"

Lots of reasons, I expect. The things have existed since Congress created the extension system with the Smith Lever Act. Let me strap on a proxy chain and go visit a government website, and I'll see if I can find something short. Okay: "...created the extension system to address exclusively rural, agricultural issues. At that time, more than 50 percent of the U.S. population lived in rural areas, and 30 percent of the workforce was engaged in farming." Yeah, lots of reasons.

Hey, why does every oil change business have their employees check the inflation on their customers' vehicles? I mean... It's pretty simple and easy to walk to a tire, unscrew the valve cap, stick a gauge on the valve stem, screw the cap back on, and repeat the process on the other three tires. And this "may" produce even more useful results than one gets from driving on those tires (and, therefore heating up the tires/wheels and the air within the space they define) to their local oil change business and having someone else do it. But, you know, people...

so that farmers (all sizes) and home gardeners can send in soil to be tested and the pH is part of the test

Yes, that's one of the many services that these entities provide.

and it's done in the LAB not in the field.

Huh. You got me there. Maybe I better call a state agricultural extension and ask. Er... This might take a little time; I'm still feeling a little paranoid from recently visiting a ".gov" website, lol, so I'm going to choose a state at random and head to the nearest pay phone (and they're not as easy to find as they once were, because technology has progressed to the point that the average person in this country can carry around a phone in his/her pocket instead of requiring a (relatively) huge case to store one in instead of a pocket - kind of like how it's possible for the average person to purchase an accurate handheld pH meter these days ). But I'll be back!

Here's how that call went:
"<REDACTED> State Extension office, <REDACTED> speaking. How may I help you today?"
"Good afternoon. I'm... a farmer. I understand that you folks offer pH testing for soil."
"Yes sir, that's one of the many services we provide. We can perform basic soil testing for free. If you'll tell me your name and address, I'll send you--"
"No, wait! Can't you come out to my... farm and test it right here?"
"But, sir, um... We offer this test for free. There are approximately <REDACTED> farms here in <REDACTED>, plus we offer these services to everyone who has a garden or even just a small patch of lawn. If we sent an agent out each and every time someone wanted their soil's pH tested, we would have to charge for doing so, and since we'd have to hire a lot more people, it wouldn't be cheap. And even if we did hire substantially more people, if you consider travel time to and from people's locations, you would see that it could take months for an onsite test. On the other hand, I can send you a kit in the mail and it will arrive in a couple days. It includes instructions on the proper way to collect a sample, along with a Ziploc bag to place the sample in and a postage paid envelope for you to-- Hello? Hello?"

Okay, I made that up. But think about it. Isn't such a conversation plausible?

This is fact and science.

That's why I went into this thing with an open mind and no real preconceived beliefs one way or the other. I had heard and read about slurry tests for years, but at the same time I was willing to admit that I didn't know the answer. (How about you?) I read the article you posted, the entire thing - did you do the same, in regards to the one I posted?

Look, both of these people are highly educated professionals who hold significant positions in their field. One assumes that neither of them is lying to us. But they seem to be drawing opposite conclusions. Therefore, one should consider things such as context and the sources that were drawn on for the articles. Now the latter is a bit of a problem, because the author of the article you posted didn't bother list any by name at the end of his article . He did mention one, and post a chart from it - but without knowing the name and/or author(s), it makes finding the thing "somewhat" problematic. At least I can quickly bring up article abstracts for some of (maybe all, but I didn't bother going through the entire list) the cited references in the article I linked to. Come to think of it, the author of that article didn't actually mention any particular pH meter, and from the impression I got when reading it, might not have even performed any of these tests himself but, instead, just read someone else's article and then whipped up a nice "for general consumption via the Internet" rehash / summary / opinion piece. You'll notice (if you bothered to read it) that the author of the article I chose to support my position mentioned a specific pH meter (which isn't all that expensive, and is a downright bargain when considering things such as its accuracy, it's refillable probe, etc.). And he went through the proper procedure for performing a slurry test. Which kind of makes it a valid reference document, IMHO.

But, anyway, I read the article you posted the link for. It seems a little more... geared toward a general/unknown audience. Which is fine, don't get me wrong. If you're writing a health-related article that's intended to be presented to a team of thoracic surgeons - or even to a "general" group of the doctors attending a large conference - then you would, naturally write it substantially differently than you would if you were publishing it for the general public (even though "general public," naturally, is going to include some doctors). Context...

In that article, he discusses a study that compared four in-field testing methods. He mentions that, of the four methods, the handheld pH meter produced results closest to the laboratory average, and that the pH probe gave the same result for three different samples. We all know this already, lol, and have been recommending the former for years whilst laughing at the latter ("pH probe" refers to those cheap "3-in1" devices that make excellend back scratchers, but that's about all they're good for). He showed a chart that lists the four methods along with the results (but for only two soil samples). He shows that the handheld meter is only off the lab average by .2 for one sample, and is spot-on for the other one.

I don't know how that constitutes valid evidence for an in-field test being accurate to only ±4 pH .

In that article, the author states, directly below that chart: "The accuracy of the hand-held meters is offset by cost and complicated operation. The hand-held meter is a portable version of a laboratory meter and must have the same care and calibration with buffer solutions before each use. Fresh and accurate buffer solutions are needed for each time the hand-held pH meter is calibrated. The accuracy of the hand-held meter is dependent on the operator’s care and condition of the electrode. A hand-held meter kept in a truck with a dried electrode cannot be expected to perform adequately. Improper storage and treatment of an electrode will not only produce poor results but require replacement before the meter will again perform to standard."

We all know that, too. Or at least we certainly should. After all, we've been discussing proper care and feeding (lol) of pH meters since at least as far back as 2009 on this very forum, and probably longer than that, but I've only been following threads here since I became a member. "The accuracy of the hand-held meters is offset by cost and complicated operation." IMHO, they're pretty reasonable in price (and I'm poor!). The operation isn't complicated for anyone who can read and follow simple instructions that are written at a fourth-grade comprehension level. "The hand-held meter is a portable version of a laboratory meter" Okay, I agree with that statement. And think, for just a moment, what that statement implies.

And the rest of the paragraph is just things that we know (or, again, should know). And, yes, that includes the statement that the things really should be calibrated before each use. At least for maximum accuracy. That information is readily available from manufacturers' websites. We don't always, or perhaps even often follow best practices when it comes to our pH meters. But we can. There's a difference between accurate and accurate enough. The one, naturally, requires more stringent practices than the other. You're not stupid, so you must know this.

So I really cannot understand what your motivation is, here. Unless - and this is purely speculation on my part - you happen to be one of those personality types who, having stepped on the old trap, either refuses to admit it or else refuses to believe it ("I can't be wrong!!!"). Me... I'm just an old hillbilly, lol, and am wrong lots of times. I don't get all frazzled when I get schooled. When it happens, I admit it. I'll often even thank the person for adding to and/or correcting my knowledge. But... whatever.

Buy decent tools, take care of them, and use them properly... and they tend to work pretty well.

Again, I don't disagree with Sam Angima, as such. I just realize that it's important to view his article, such as it is, with an understanding of the context of the thing and it's apparent intended audience. To read the entire thing, and to understand same. To approach a thing/question/concept with an open mind and to examine multiple articles/papers - instead of having a preconceived notion, searching for an article that supports that preconception... and then to stop looking.

But, hey, that's just how I do it .

If you don't believe me, thats fine and dandy.

If you were taught such things in Debating 101, well... I hope you didn't have to pay much for the class .

Do your pH slurry test from your soil, then send that same soil into your state soil lab and have it tested. Compare and report.

I probably should. A slurry test is one of the primary methods... that the testing labs use (FFS, lofl). The meters are somewhat more accurate, they're generally calibrated more often, and the employees use an auto-stirring device, but basically. I haven't done exactly what you suggested, but I used to hang out a good bit in a municipal wastewater treatment plant's laboratory during the midnight shift (should have gotten paid for training two of their employees, or at least for calming one of them down and explaining how to set things right after he got a little too high on his second night, wandered off, and returned right after the alarm went off to say, "I think I might have f*cked up," lol - but I was into certain other substances back then, the making of which required lab equipment. So it worked out...). I've compared my results with my inexpensive Milwaukee pH56 to the "proper lab test" procedure using high-end ($10,000+) constant-monitoring lab grade stuff, and they comparable. I use the term "comparable" because my Milwaukee only reads to two decimal places instead of four. Now if you want to talk EC/PPM, no meter I've ever used can compare to taking a sample, flash-drying it, then weighing the residue on a scale that's accurate to a ten thousandth of a gram. But one must simply make do the best that one can, I suppose .

I'm just saying that your slurry test is NOT accurate

Yeah, exactly - you're just saying. Try reading a little more, lol.

pH is a logarithmic

I believe I might have mentioned that in the post immediately preceding the one of yours that I'm quoting from.

I depend on my local extension service to do this test for me. I feel pretty good about the result. A soil test is much cheaper than a test probe. My cost is $8 includes everything I need to know about my soil including pH.

Whatever works for you. And it does work, of course. You're correct about the cost factor, too. Even my little meter was $60+, and the last time I bought a probe (pH junction, whatever they're technically referred to) for it, it cost me something like $32. It's the second one I've bought, so... Maybe $126? That's enough for 15 of your local ag extension office's tests, I suppose. Then again, I've done more than 15 pH tests in the last ten years...

As an example of how a slurry test is done and it won't be accurate:

Take tap water with say a pH of 8 and do your slurry and test.

So if I state that, since frying an egg at 550°F for nine hours will produce something inedible, that we should only be eating breakfast prepared by master chefs, that would be evidential, in your opinion? Because that's pretty much what you've just done.

When I argue that a slurry test will produce accurate enough results for our purposes, I am, after all, presupposing that the person performing the slurry test... does it correctly . I'm just sayin', lol.

That 8pH of your tap water is going to skew your results BIG TIME and give you wrong results. Lets say your now want to lower your soil pH and you adjust accordingly. You going in blind. No way you're able to achieve the result your looking for.

See above.

Lab testing removes all variables. Thats my argument.

Gotcha. Why didn't you just post "People who can't be trusted to pour p!ss out of a boot even if the instructions are written on that boot's heel... should have someone that has a modicum of sense do their pH testing for them," lol? I'd have agreed with that.

We are paying for these labs (extension service - soil labs) with tax money. Take advantage of them.

Well, fawk, I wish I'd have thought of that argument 20 years ago. Because we pay for the welfare programs, too, and it's probably a lot easier to walk to the mailbox and collect a check once a month instead of hustling work.

Oh, it almost slipped my mind (have been doing several different things simultaneously). While I was (unsuccessfully) attempting to track down the source reference that wasn't actually mentioned by name in the article you posted the link to, I did happen to find a published article titled Determination of pH of Soils by Different Methods:Collaborative Study. They also collected samples and sent them off to labs. They didn't use a couple, or even a few samples - they used lots of samples, and lots of labs from multiple countries:

"Fifty-three laboratories from Canada, India, Israel, and the United States participated in this collaborative study. To make the methods as widely applicable as possible, a broad range of soils differing in pH, texture, organic matter, and other properties, was selected."

This article is helpful, IMHO, for a number of reasons, including the fact that the author explained the testing procedures pretty fully (it's well worth a read, especially for people who are interested in performing their own tests - so you might choose to skip it, IDK). But one thing that I noticed that surprised me was the variance in the lab results. On pages seven and eight of the document, there are two charts (two testing methods were used). I'm not even going to try to reproduce those charts in a forum post (but I will include a link to the article). However, I'll list some test results for the first sample: 5.90, 5.48, 5.18, 4.92, 5.64, 5.30... 7.08, LMFAO. Thanks, but I'll stick to performing my own pH tests .

https://www.researchgate.net/profile/Raju_Thapa3/post/What_is_the_principle_and_the_method_used_to_measure_the_pH_of_soil/attachment/59d6534479197b80779ab3c2/AS%3A516185469210624%401500079614689/download/1.pdf

BtW, distilled water is good for some soils, but might not give the most accurate results for others. That was probably mentioned in the above document, but if not I could probalby find the information on thesubstance/strength/explanation again.

 

[Emilya Green]

and in the end, a long discussion of soil outside in the field, even by very distinguished scientists, has very little to do (and this had nothing) with growing medicine in a container. Just come in at 6.3 pH and all will be fine. 'nuff said. Sensible Emmy, out.

 

[TorturedSoul]

and in the end, a long discussion of soil outside in the field, even by very distinguished scientists, has very little to do (and this had nothing) with growing medicine in a container. Just come in at 6.3 pH and all will be fine. 'nuff said.

Lol, no doubt.

So... how are they supposed to do that, exactly? <WINK>