Soil pH Testing- ever done it?


King of Splices
Mar 30, 2005
Snowless California
I do a lot of planting consulting- guiding people on what kind of tree to plant. Currently, I base my decision on what would fit the space and what would fit the new owners' desires (shade, flowers, evergreen, etc).

I'd like to be more confident that the soil is a good match for that tree. I have books that tell me what kind of soil the tree would like, but I don't have a way (yet) to know if a particular site has a high pH level, is low on nitrogen, etc.

Have any of you ever tried the small affordable kits that are out there? I see some products like this one that run $50 and give you enough to do 25 tests. I've seen other products online (via the google shopping button) that will let me do about 5 samples for about 50 cents per test.

Any tips?

I have a Hanna TDS meter that I used to use with hydroponic setups, lost my pH 'pen' a few years back. They were/are good indicators in liquid, PITA in a slurry. Doing the math to figure the water pH, the soil, the amount of water to soil volume etc was a skill I didnt take the time to master.

The color reagent type tests are also a bit of a PITA with a soil slurry, you have to wait till the sediment settles then take a gander at the remaining liquid compared to a little color sample chart.

I have a couple of those $8 pH measuring devices that the garden shops sell, probe is about 12" long with two different metals at the tip, measuring pH via soil conductivity. They are cheap and cheezy thats why I use two, if they both read the same and it seems out of wack I consider a lab test to be really accurate, catch is, that goes to an independant lab and costs about $60 per test.

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You know, I wouldn't mind paying the $60 per test. Honestly that cost, plus a processing fee would just get passed on to the customer. This is LA. I think a statement like, "a lab test is $80, but considering this is a tree you'll have perhaps for the rest of your life...."

But if there is a way to do it moderately reliably and more affordably, sign me up!

lab test wise here, they want about 2 cups of material, damp, in a ziploc. Takes them a few days then you get a printout with organic material %, pH and mineral levels including the einsteinium, VERY complete. Usually I will take a few shovel fulls from the test area, mix it in the wheelbarrow and extract the sample material fromthat. I think it gives a good general soil profile.

and yes, pass that along to the client and charge them for time to send or drop off the sample AND time to get the results and explain it to them.

For consulting on trees I usually carry a soil core sampler; very good at getting a soil profile, the 2 pH meters and my mini pulaski for digging.
Soil is interesting to me, I am going through a soils book I got at the college bookstore (second, maybe thirdhand) and I have a friend that has told me some of the field basics for analysis like smells, colors etc.
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I remember joking with kids that took soil classes offered by the Ag department in high-school. Now I wish I was right there taking notes alongside them!

I'll have to find a lab around here that can do the testing.

I took a short course at Penn State and we had a soil scientist do a presentation. One student called it "dirt" and I actually thought I saw a tear in the profs eye.

He seemed to think that basic on the spot tests could tell you 99% of what we need to know, pH, compaction and soil type (sand, loam, silt).

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Tom, by spot test, I'm assuming you mean it's something that gets done right on the spot. This would be by doing a slurry of some sort, then dipping something into the water then comparing colors?

I wish there was a more definitive way.

I also think there'd be a value in doing spot tests, then sending stuff out to a lab to check your math. After a while, you might find that the lab stuff really is or isn't necessary.

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There are tests that will show you how much is in there, and it's up to you to find out how much it is "supposed" to have for what ever it is you are dealing with.

Soil tests won't be a realistic option for people until the remedies for soil deficiencies become realistic. So my soil is alkali... am I supposed to spend a b'zillion dollars amending it ?
Just my .02
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They are realisitic, for some people. I live in of "I have a ton of money and want to be better than the neighbors." Every job I see, I tell them EVERYTHING that ideally should be done. I've seen people pull up tons of grass based simply on the word that I said it is bad for the tree. I convinced a homeowner to convince the developer to change the planned trees for their site. The developer was going to plant Tipu (Tipuana tipu) trees. I knew (thanks to sunset garden guide) that the tree doesn't like high alkaline soils which is exactly what they had on that site.

The owner spent a few thousands getting the developers to change the tree to another species...then later on they decided they wanted uniformity throughout the development so their solution....they are taking out all the fill on that area of home and bringing in the right soil for the tree!

Friggin ridiculous, but they have the money and know what they want. If I would've shopped for them with MY pocket book, I woulda came to a different conclusion that was more along the lines of, "well, we'll just have to cross our fingers."

Velsicol Corp. sells box kits to chemistry labs that include a "pen-style" pH meter, and two standard reference solutions. It's really important to standardize you pH meter with a solution of known pH to calibrate the pH meter. Frequently, their off by a bit, and need to be standardized and recalibrated.
For me it's more realistic when determining what tree to plant in the first place. Around here, unless you're on a culm bank, there aren't going to be prohibitive mineral deficiencies. It's rare you'd have to go further than pH, does it flood, how much clay, sand etc. To get folks to remedy ($), beyond mulch and water, would be difficult.

Glad you're back Theresa.

I asked my extension about the ph testers. He said the probe ones are hokey. He said the dimpled well type that you put soil in then solution , mix and get some solution to drain out and then check the color do work. I did master using them but there is a bit of a learning curve. Checking for nutrients is a bit more complicated and i think a lot of them are gimicky. The ph well tester is very cheap . Check with your ag extension agent [county or state]
I took a soils class at Santa Rosa Junior College in 1972. About a 16 week course. Very intensive and the teacher expected full partisapation in such mundane matters as "dirt"

The methods we use to measure PH and NPK, were done mostly with dyes and color comparison charts. Particulates of course were measued by suspension and settleing characteristics, and shifting in the field. Very timely, but fairly accurate for the time. I really don't know if the methods we used to test soils then have been improve upon today even with all the latest technology.
We can get a complete soil test done by the ag extension or independent soil test agency for 20 or 30 dollars. The 25 test for $50dollar deal looks like it could be ok. You could try one and check with a lab soil test to verify.
Mr. B you was testing soil before most of us came along.:)

I'll share my experience for what its worth.

I was living in Brunswick, Ga. AkA(brunstink) thanks to this huge Hercules plant that spews tonnes of wood and chemical waste into the town via smoke stacks daily. They turn fat lightered stumps into gunpowder and toilet paper. Probably the largest employer of the town.Venturing out on my own I decided to do free soil testing on beautiful live oaks as part of my service. It was free to me via the county extension agents and the homeown got a printout and I got a print out of what was in the soil. After about 25 samples one client says, "Hey does it show toxiphene?" We looked at his read out, I siad, " I guess it dont whats toxiphine (sp)? Well, he said your gonna cut Joe's tree next arent you I said yes just a trim job. Are you gonna test his soil? Why yes sir, its standard and free and give the homeown an idea of what to add or subtract to his trees." He thought for a moment and said. "Hercules, pulled a add in the paper 10 years ago giving away free mulch to all these residents, they said there was some dirt mixed in with it and it would be great for your yards and besides it was free. You know joe got some of that dirt and his family member got sick and died cause of it. No way I said. Yes he said they just now 10 years later finished up the settlement in court it went class action and over 50 people sued the plant and won. Did alot of people die from the free dirt I ask, yes he said allot of them did. Well I wont be testing Joes dirt then. And I haven't tested any since.
I remember checking out my soils, I was really surprised at how different they are here from one side of a field to another. I did a quick google (soil layers mix jar settle) and found a bunch of pages that describe it: This one sounds close to what I did.

This might be of interest to your customers in their (your) decision making.....

We get all our soil testing done by the county extension here, too.
Gerry B, as said, you were testing soil before some of us were concieved... :) just curious were you in that class in the spring or fall, I was born in Aug 72.... :D
Nick, FWIW I've seen grand old tipu trees growing very happily in what was essentially crushed coral.

Here's something that might be useful.


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That's a good visual to add here, Leon. It helps to use this chart when explaining to customers why iron chlorosis needs to be addressed by more than simply pumping iron into a tree or soil.
People seem to understand soil(s) better when I use the analogy of how the human body uses nutrients >>> If you are pumping your body full of vitamin C but are B12 deficient, it cannot be utilised.
It takes a balance.