One of the most important factors to whether or not a plant will thrive is if the soil is acidic, neutral, or alkaline.
Even the pH being a little bit off in either direction can have disastrous effects on your plants.
That’s why it’s so important to use the best soil pH testers to make sure your plants are getting the nutrients they need to be happy and healthy.
Table of Contents
What is Soil pH and Why is It Important?
The main reason that soil pH is so important is that it determines the availability of all the nutrients plants need.
A pH of 6.5 is generally ideal but that number varies depending on the plant species as they all have different requirements.
If the pH is too low, the soil is acidic and nutrients like phosphorus are less available while other things can accumulate and become toxic. Soil that is too acidic is also not a good home for beneficial bacteria.
On the other hand, soil with high pH is alkaline and prevents the plant from having access to iron, manganese, copper, phosphorus, and zinc. Iron is very important to all plants but especially important for evergreens.
The Best pH Testers For Garden Soil
You can see why it’s so important for you to test the pH of your soil if you want your plants to thrive. Let’s take a look at some of the best soil testers out there so you can find the one that’s right for you.
1. Sonkir Soil pH Meter MS02 3-in-1 Soil Moisture/Light/pH Tester
One of the great things about this meter is that not only does it check pH, it also tests moisture and sunlight levels, too. You can make all the right adjustments to ensure that your plant is getting just what it needs.
It’s really easy to use, too, just insert the double probe into the soil about 2 to 4 inches and toggle the switch to what parameter you want to measure. It takes about 10 minutes to get results.
Another great thing about this meter is that it’s battery-free so you don’t have to worry about it losing power any giving inaccurate results.
Pros
The premium double-needle detection technology enhances the speed and accuracy of all readings.
You can easily carry this portable soil pH tester around for indoor or outdoor use.
Tests pH from 3.5 to 8.
This product is covered by 12-month money-back warranty and after-sale support.
Cons
Customers have few complaints about this product.
2. Atree Soil pH Meter, 3-in-1 Soil Tester Kits
This 3-in-1 soil tester kit is easy to use and a helpful tool for growing any type of flowers and plants. Simply insert the probes into the soil between 4 and 6 inches down and flip the switch to what you want to read.
Next, twist the probe slightly until you start to see the needle on the monitor move. Allow the meter to sit for about 10 minutes before you take a reading but be sure not to leave it in the soil for too long.
One more thing, because there are no batteries, you don’t have to worry about recharging or getting an inaccurate result from a lack of power.
Pros
You can use this probe both indoors and outdoors so you know when to adjust pH, water your plants, or change the lighting patterns.
There are no batteries required, just plug and read.
This inexpensive monitor gives accurate results.
Cons
This machine takes about 10 minutes to get a result.
3. Luster Leaf 1601 Rapitest Test Kit
For a simple test kit that measures soil pH, nitrogen, phosphorus, and potash, check out this innovative setup from Luster Leaf. It gives you quick, at-home results for nitrogen, phosphorus, and potash.
This meter is a little different than what we’ve seen so far. It uses small test kits and color-coded comparators rather than a probe.
To test pH, mix the soil with the green capsules, add a few drops of water, then compare the final color to the scale on the bottle.
Another great thing about this kit is they include a pH preference list for over 450 different plants so you know just what adjustments to make.
Pros
The easy-to-use color-coded capsule system gives you quick and reliable results.
This kit comes with 40 test kits in all, 10 each of soil pH, nitrogen, phosphorous, and potash.
Simple, detailed instructions are included so even beginners can get accurate results.
They include a soil pH preference list for over 450 different plants.
Cons
Results can be inaccurate if the process is not followed carefully.
4. Gain Express Soil pH & Moisture Meter
This meter uses a single, easy-to-use probe that measures pH levels between 3 and 8. It can tell you the moisture level, too, just press the button on the base for an accurate reading. Because it doesn’t require batteries, it’s always ready to go when you are.
One of the nice things about this meter is it’s really lightweight so it’s easy to take with you wherever you need it. The probe is really long, too, so you can even get soil readings deep down by the roots.
Pros
This meter requires no preparation at all. Simply push the probe into the soil and you’re ready to go.
The probe is about 11.5-inches long which means you can get all the way down to the root of the plant.
The waterproof metal probe passed strict quality and safety standards and is suitable for the agriculture field or for educational experiments.
Cons
This probe can be difficult to stick in the ground and calibrations are sometimes off.
5. Bluelab 716441 Combo Meter for Plant Germination
If you’re looking for a pH meter for hydroponic farming, check out this combo product from Bluelab. It measures pH, temperature, and conductivity so you can make the adjustments you need to keep your plants on track.
This is a lightweight, extremely portable meter that has a really long probe cable of 6.5 feet which makes it really easy to stretch to get whatever readings you need.
It has a simple, easy-to-read digital display and the buttons are clearly marked and easy to use.
Keep in mind that this meter is specifically made to test water for hydroponic farming and is not to be used with soil.
Pros
Meter is powered with two AAA batteries and is equipped with a low battery indicator and auto-shutoff feature so you don’t accidentally run out of power.
pH Calibration is done with the simple push of a button.
Includes a 5-year limited guarantee.
Cons
Instructions can be difficult to understand.
Results can be less accurate over time.
6. Luster Leaf 1606 Rapitest Digital Soil pH Tester
This digital soil pH tester from Luster Leaf makes it easy to determine soil pH. It uses a special optical calibration system and advanced LED technology to read soil pH and gives you results in minutes.
While the instructions are extensive, they’re easy to follow so you can trust that you’re getting accurate results. It includes a test tube, 10 test capsules, and a liquid dropper so you have what you need to do 10 tests right out of the box.
One of the great things about this tester is that it comes with pH references for over 450 plants. This way, you know how to apply the results and what you need to do to get the right pH for your plants.
Pros
This product is designed and engineered in the USA.
The results from this kit are accurate and reliable.
You can order more test capsules so you can continue to use this kit for a long time.
Cons
The test capsules can be difficult to open and this kit only comes with 10.
It can take up to five minutes to get results.
7. Luster Leaf 1836 Rapitest Dig 3W Analysis
This pH soil tester from Luster Leaf is easy to use and, in addition to giving you an accurate pH level, it also measures soil temperature and fertility.
Results are displayed digitally and are easy to read. The screen displays one result at a time. Cycling through them is easy, just press the up and down arrow buttons until you see the result you want.
All you have to do is insert the probe into the soil and read the on-screen results. Note that the probe is a bit fragile. It should be cleaned before every use and should never be forced into the soil. It could break if it hits a rock or if the ground is too hard.
Pros
This pH tester was designed and engineers in the USA.
Both pH and fertility are auto-adjusted based on soil temperature to give the most accurate results possible.
Fertility takes into account the N, P, and K levels and gives a reading between one and 10.
Cons
Cleaning and care of the probe can be a bit tedious.
8. Garden Tutor Soil pH Test Strips Kit
These test strips from Garden Tutor are specifically calibrated for pH testing and deliver quick results. Each strip measures pH between 3.5 and 9. They deliver much more accurate results than universal test strips that are not specifically made for pH testing.
This kit includes a 16-page handbook with sulfur and lime application charts based on your soil’s pH. Most garden plants prefer a pH of around 6.5 and this handbook tells you how to get there.
Considering how many tests this kit performs, it’s extremely affordable. The process is a little involved but the instructions are easy to follow. The whole process takes about 20 minutes or so.
Pros
This kit comes with 100 test strips so it could potentially last a really long time, depending on how frequently you test your soil.
Results are determined using the easy-to-read color chart on the side of the bottle.
Because these strips are designed to only measure pH, testing is reliable and accurate.
Cons
The testing process is tedious and takes a lot longer than other testing methods.
9. Bluelab PENSOILPH pH Pen
This pH testing pen from Bluelab uses a lab-quality glass probe and can be used to measure pH in a variety of places. It’s great for soil testing but so accurate that it’s also used for testing swimming pools, water, brewing, and hydroponic gardening.
Calibration is easy and ensures the accuracy of the results and the probe automatically compensates for the temperature. The backlit LCD display is easy to read and also reminds you when it’s time to calibrate.
To test soil, all you have to do is insert the probe. Just make sure it’s soft and that there aren’t any rocks in the way. It reads pH from zero to 14 in temperatures between 32 and 122F.
Pros
This kit comes with the probe, a AAA battery, calibration solution, and a storage cap.
It’s covered by a one-year limited warranty.
The probe is fully waterproof.
Cons
This is on the extremely high end of the price range.
10. Yoyomax Soil Test Kit pH Moisture Light Tester
This probe pH tester from Yoyomax features a three-in-one design that tells you not only the pH but also the soil moisture and whether or not your plants are getting enough sunlight. Plus, you don’t need to worry about batteries or anything like that. It’s ready to go right out of the box.
All you have to do is set the switch to what you want to measure – pH, light, or moisture – then insert the probes about two to four inches into the soil. Wait for about 10 minutes and read the result. It measures pH from 3.5 to 8.
This probe is small and portable so you can use it just about anywhere. It’s great for container plants, especially for houseplants. Not only can you determine if the soil pH is accurate but you can also make sure they’re getting the right amount of light.
Pros
No batteries or electricity are required.
It also measures light and moisture so you can get a good overall picture of the condition of your soil.
This probe is extremely affordable.
Cons
It takes about 10 minutes to deliver a result.
What is the Best Soil pH Tester?
Our pick for the best soil pH tester is the Sonkir Soil pH Meter. Not only does it provide accurate pH readings, but it also checks for moisture and sunlight levels, too.
It uses double-needle detection technology to enhance the speed and accuracy of the readings and is simple and easy to use.
That’s not all, one of the best things about this portable soil pH tester is it’s covered by a 12-month warranty and includes after-sale support. This is the best warranty coverage we found.
How to Test Soil pH with pH Meter?
While each tester works a bit differently, they do have a lot in common. Since most of these meters use probes, here’s a general process for how to use them.
1. Clean and Calibrate
Turn on your meter and let it warm up for a bit. This usually takes about 30 minutes but you should check the specific instructions for your meter to be sure.
Next, clean the electrode by taking it out of the storage solution if needed and rinsing it with distilled water.
Once rinsed, blot the electrode dry. Don’t rub it because you could disturb any sensitive membranes or scratch the metal surface. If the distilled water isn’t enough to clean it, check the manual for your tester and use the cleaning solution they recommend.
Some soil testers require buffers for calibration. Check with the manufacturer to be sure. This is how you make sure that the probe is reading accurately. Once you’re used the buffer, discard the leftover liquid and don’t reuse it.
2. Using Your pH Meter
Using your tester isn’t always as easy as simply pushing the probe into the soil. While you should always follow the instructions that come with your meter, here’s one way to get good results.
Start by digging out the top two inches of soil from various places around the planted area. That includes different parts of the bed as well as soil from different depths. pH can vary widely from place to place and from one layer to the next in any garden.
Place all the samples you collect in the same bucket, mixing thoroughly and being careful to remove any rocks as they can damage the probe. Measure out about two cups of mixed soil into a clean container.
Add distilled water to the soil and compact it into the container. Turn on the meter and, using a clean probe, insert it into the soil. Twist it to make sure you have good contact all the way around and keep the probe away from the bottom of the container.
Next, you have to allow the probe to sit. How long will depend on the manufacturer but it can range anywhere from 60 seconds to 10 minutes or more. Once the allotted amount of time has passed, note the reading.
If you’re using a test kit with test strips or color-coded capsules, be sure to follow the instructions carefully. For some of these kits, different color testing media is added to the soil and activated with a few drops of water. Comparing the final color to the included chart will give you the amount of pH.
3. Clean up
Proper cleanup is important because it makes everything easier for next time. Rinse the electrode in distilled water and blot dry. Then, store it away until next time. Consult your manual for optimal storage practices.
How to Raise and Lower Soil pH?
One important thing to keep in mind before making adjustments is that not all plants prefer neutral pH.
For example, plants like blueberries and azaleas thrive in acidic soil whereas some plants, like lilies and hyacinths, prefer alkaline. Make sure you’re adjusting the soil to what your plants prefer.
The pH scale ranges from 0 to 14 with a pH of 7 being neutral. Below 7 is considered acidic, above 7 is alkaline. Most plants prefer a pH that’s between 6, which is slightly acidic, and 7.5, slightly alkaline.
If your pH is off, you can either choose plants that prefer the soil you have or change the soil’s pH to suit your plants.
Sphagnum peat. An added bonus to using sphagnum peat is that it’s also a great source of organic matter and can also act as a fertilizer. Add one to two inches of peat and work it into the top 8 to 12 inches of soil to make sure it’s available for the roots before planting.
One downside to using sphagnum peat can be expensive to use on a large plot of land but for potted plants, gardens, and flower beds, it’s a great choice.
Granular sulfur. This is the least expensive and safest option for lowering pH. The downside is that it doesn’t work very quickly. Note that you should less on sandy soils and more for clays.
Don’t apply more than two pounds per 100 square feet with each application and don’t reapply too soon. Remember, it works slowly so you’ll have to wait a while to see results. It’s best to wait three months between applications.
Aluminum sulfate and iron sulfate. These products are much faster than sulfur but they have to be applied at a much faster rate. Five to six times more often, in fact.
Don’t apply more than five pounds per 100 square feet of aluminum or iron sulfate at once. Too much can be harmful to your plants.
Fertilizer. Some fertilizers that include ingredients like ammonia sulfate, urea, ammonium nitrate can also acidify the soil. They’re generally safe to apply so you won’t have to worry about using too much. Check the label to determine if it’s acidifying.
How to Raise Soil pH
There are a few common causes for low soil pH that should be evaluated before treatment because removing the cause can correct the problem.
Inappropriate fertilization can cause this kind of problem, especially with ammonium-based fertilizers.
If you live in a particularly wet climate, know that high amounts of rainfall can cause high acidity as can soil that contains consistent decomposing organic matter.
Finally, the native vegetation can also lead to problems. For example, soils that are formed under forest vegetation tend to have a lower pH.
If you can’t identify a cause, there are some ways to correct the problem. Here are some things you can use to raise soil pH:
Lime. This is the most common choice for raising pH but there are a few ways to use it. If applied directly to the surface, it usually only affects the top layer of soil. It’s best to mix it before planting when possible.
Because lime has low solubility, you can’t apply it through irrigation or count on water to pull it into the soil. Keep this in mind when preparing to plant.
Potassium carbonate. If you’re looking for something that’s highly soluble, try potassium carbonate.
It can quickly and easily be applied through drip irrigation and distributes throughout the root zone to reach deeper into the soil.
Potassium carbonate can have rapid effects and is a great choice for soils that consistently drop in pH. It can even be applied regularly for maintenance.
How Accurate are Soil pH Testers?
While they may not be as accurate as having soil sent out to a lab, soil pH testers can give you reliable and consistent results. If you want to get the best results possible, there are a few things you can do.
First, make sure you’re using the tester accurately. Read the instructions carefully and follow them exactly. Make sure you’re placing the probe deep enough and waiting long enough to get an accurate result.
Next, make sure you clean and store your tester appropriately. Probes should be cleaned using distilled water both before and after use. Always be gentle when cleaning and be sure not to rub the probe too hard because it could cause damage.
Finally, calibrate your tester if recommended by the manufacturer and make sure to use the buffers they suggest. This usually involves calibrating the probe to a neutral, acidic, and alkaline liquid.
Conclusion
In order to make sure your plants grow to their full potential, proper pH is important. If you notice that leaves are turning yellow or any other anomalies, checking the soil pH is a good place to start troubleshooting.
It’s important to use the best soil pH meter available in order to get the most accurate results, especially if you’re treating the soil to correct the pH.
If you have done treatments to raise or lower the pH, make sure you start with a reliable base reading. Then, recheck periodically after treatment to be sure you’re getting the right results. This can avoid any over-correcting which can lead to other problems.
Also, keep in mind that a lot of the products we chose to test for multiple factors so you can really check the overall health of your soil to make sure your plants are getting everything they need.
I watched my probe change values while just sitting there. Further, I tried calibrating and got inconsistent results. The worse part is that the probe instructions tell the user to directly insert the probe into the soil without saying a sample should be removed from the ground or moistened with distilled water. The typical user has ZERO ways of knowing proper use from the instructions.
I tried the RapiTest as well. It is extremely subjective and problematic. Even if I let the test sit for over a day, fine clay suspended in the solution (plus other material?) altered the solution color so it didn’t match ANYTHING on the color scale. For example, the pH test ranges from orangish to greenish. My test water, even after sediment settling, was a brownish greenish grayish color. So, unusable. Also, the tests are poor for the 8-10 percent of men who have color vision problems!
Any test is also fairly useless giving a single number, so mixing the soil is not a good idea. My yard has various layers in different locations. Mixing them into one sample gives an average, but one should know the pH of ALL samples because roots encounter all of those places with different responses. In the end, I think all I could determine was that my yard needed nitrogen badly, but other things were probably OK. Specificity is elusive.
Is this a joke? These ‘probes’ are notoriously inaccurate.
I watched my probe change values while just sitting there. Further, I tried calibrating and got inconsistent results. The worse part is that the probe instructions tell the user to directly insert the probe into the soil without saying a sample should be removed from the ground or moistened with distilled water. The typical user has ZERO ways of knowing proper use from the instructions.
I tried the RapiTest as well. It is extremely subjective and problematic. Even if I let the test sit for over a day, fine clay suspended in the solution (plus other material?) altered the solution color so it didn’t match ANYTHING on the color scale. For example, the pH test ranges from orangish to greenish. My test water, even after sediment settling, was a brownish greenish grayish color. So, unusable. Also, the tests are poor for the 8-10 percent of men who have color vision problems!
Any test is also fairly useless giving a single number, so mixing the soil is not a good idea. My yard has various layers in different locations. Mixing them into one sample gives an average, but one should know the pH of ALL samples because roots encounter all of those places with different responses. In the end, I think all I could determine was that my yard needed nitrogen badly, but other things were probably OK. Specificity is elusive.