Soil pH testing meters

Any body here use them and how well do they work?
Have you ever compared their readings to a professional soil test?

We have a very simple one which is surprisingly fairly accurate although it is affected by the pH of the water used to mix the soil.

They are not reliable as far as I know. Unless things have changed over the years. I am not aware of any improvements. Maybe someone can prove otherwise.

I have one that has a metal spike about 8" long which seems to work very well. I did some (not very scientific) testing of it. My soil is acid (typically 5.5-6 pH). I make compost that is neutral. I took equal quantities (a bucketful) of soil and compost and then sequentially added lime (by the tablespoon) to each specimen, mixing very thoroughly after each addition. The pH, as measured by the meter, went up, initially, very much proportionately to the amount of lime added.

Separately I mixed equal quantities of soil and compost with the result of a pH of just over 6... There would be precious few plants that need pH in the range ± 0.5 ....

I guess they can't be that inaccurate...

Mike

I may be in the minority here, but I think almost any pH testing method that you use at home is more accurate than "professionally" or extension service done ones. They direct you to take samplings from various areas and then mix them together. What is the point of that? The results you get are a statistical average of different areas which doesn't seem to me to be very helpful. If your entire lot has not been amended then it should be the same whether you take a sample from one area or 20. If it has been amended, mixing soil from an area that has been amended with peat and soil that has been amended with limestone only negates the results of both and provides you with a statistic that is accurate for neither..

I don't like the averaging approach either but, for different reasons. Soil itself can vary over short distances. That is especially true in my gardens. Each bed/garden is "tuned" to the plants growing there. Getting an average of my entire yard doesnt make sense..... for me. Averaging each bed/garden does.

You said it better and more sucinctly than I did John. That is exactly the reason I attempted to address.

most extension agents also have a Hanna Ph/EC meter. ask them to do a pour through test if you are so inclined.
Essentially, you measure the ph of the water, than flood a plant for awhile and test the water comming out of the pot. The ph will be different.... with this info you can figure the ph of the media. You can also measure in ppm Nitrogen and many other things.

It will measure ph and soluable salts, or tds (total dissolved solids).
one of these combo meters costs $120 or so.... a Hanna ph meter should cost $50 or so and last literally a lifetime.

ie, you get whatcha pay for. Don't expect a $5 meter from walmart to be worth anything more than $5.

drew

Absolutly, drew.

I am looking at the Rapitest Soil PH meter, which I see in a catalog for $26.95. They say it ...

"Measures pH on a zero to 9 range, and the relative levels of Nitrogen, Phosphorus and Potash (ppm) in the soil."

Anybody ever use one of these?

No, But I'm interested in what everyone has to say. I'd like to get one too.

I have the cheap pH only meter - it's not very accurate & a little hard to read but it's good enough to get it into the 6-7 range that vegetables like. I had soil samples taken and the lab said to add 2 to 2.5 tons per acre which is about 40 lbs. for my 14'x28' bed. About the same result I figured with my cheap tester. My soil seems to run between 5.5 & 6 before I amend it. The meter came with a little chart on various plants & recommendations for liming which is helpful. I've heard the NPK test is even less accurate but I just keep adding a balanced NPK organic fertilizer & compost when I plant. I add extra nitrogen (blood meal) if growing green leafy crops.

Here's a online link for Hanna meters: http://www.specialty-lights.com/meters.html . Does The Hanna only test liquid? With my probe, I can stick in the wet, muddy (red clay) dirt (that I'm trying to turn into soil) & get a quick & 'dirty' read-out. Poor pun, sorry;)

This thread got me interested in buying a better one but I like the convenience of the cheap one. On the more expensive models, is the TDS (total dissolved solids) reading of any value to gardeners?

I also have the kit with the colored tablets & plastic vials that seems fairly accurate but time consuming like a pool test kit.

Also, none these kits/probes give trace elements. According to my soil test, I'm suppose to add Zinc & Manganese which I'd never known had I not had the analysis done.

Photo below is of a rapitest(r) mini pH tester - stapler added for scale.

thanks, Jozeeben, that's pretty much what I wanted to hear! I'm thinking that since I am only growing veggies for our own consumption, I don't need to make this into rocket science. If the cheap meter gets me in the right neighborhood with the ph, that's close enough for me. I've been adding a lot of compost to my garden since I had the lab test done, and I am wondering if my black gold is really making much of a change in the ph. I like the convenience of being able to just stick the meter in the ground and get a fast read on where we are ph-wise. I'm going to buy that one for $26.95. We'll see how it works.

Whopeeee!! I got my new PH meter yesterday! I've been running around the house sticking it in every potted plant and a bag of potting soil checking the readings. It's raining outside so I can't go out and run around the garden and flower beds testing everything - but it's gonna stop raining sometime!! Like a kid with a new toy - YES!

hmstyl,
Let me know how the pH meter works... I've been thinking about getting one, and would like any info about it if it's worth getting-
Thanks,
Mara

GRRR - pet peeve. I have one - everyone tells me it works but I notice that if it is in the sun it will register more alkaline than in the shade. Literally would register a different number (drastically) if I shaded it with a hat. Frankly I didn't trust it - had the extension service test it also

I don't trust them either roxroe.

I use a Oaklon waterproof phTestr 2 that I got from www.benmeadows.com The accuracy is pretty good. I got this ph tester last year and I have been able to get better ph level reading's compared to other's that I have use.

How do you vouch for its accuracy?

In the past using prong type ph meters, I never got the correct reading compared to the lab results I got back. So, I asked the tech at the lab what ph tester I could buy giving me results as if I took the samples to a lab and he recommended the Oaklon. I got it and took samples, did a test, wrote down the results, took the same sample to the lab, they did there testing and the results were the same as what I got. I had the meter with me and they used it to see and the accuracy was on the money. There is alot of junk meters out there and for what I paid for mind, it better work. I also have a testing kit ordered.

Good testamonial. I will keep this in mind. Thanks.

LaMotte, Hach, Hanna, Oakton are all good meters for simple analysis. There are many in these manufacturer's product lines that are very accurate, they do, however have a probe that either needs to be stored wet or replaced after each test. I think that the easiest pH test is currently either the test paper or the test tube method. Soak a measured amount of soil in distilled or a neutral water and dip the test paper, It's accurate enough for aquaria. The paper is cheap and it is close enough + or - .25. If one is attempting to "dial in" a potting soil or a bed, this is certainly close enough for most plants. I'm not sure I want to even attempt to get the pH of soil closer than that to a target. Especially with tap water being what it is these days...lol.