Top 5 Best Soil Penetrometer & Compaction Testers 
When testing soil conditions there are two main tools at your disposal, a soil penetrometer or compaction tester.
In fact, in many States, a pocket penetrometer is required by OSHA on all excavation jobs. To avoid costly construction delays, you should have one on-site to produce valid readings when needed.
Regulations aside, buying the right tool is important and with the number of models available on the market these days, it can be a little confusing.
- Editor’s Choice
- Top 5 Picks
- Penetrometer/Compaction Tester Reviews
- How to use a Soil Penetromater
- Further Reading
When looking to buy a compaction tester, the probe length is one important variable. How deep will you need to test? This also impacts the psi capacity. In general terms, the longer the better.
This has to be balanced against your budget and the price point of the tool too.
A pocket penetrometer needs to be small and easy to carry. You also want the indicator to be clear and easy to read. Ton per square feet is an important measuring capacity.
In this review roundup, we have selected 5 individual tools covering a range of price points and testing capacity. We have also rated them based on verified customer reviews in tandem with intensive product research and analysis.
Using these criteria and more, the following 5 models are what we consider to be the best soil testers on the market in 2021.
Top 5 Picks
AMS 59032 E-280
0 to 4.5 tons.
0 to 4.5 tons.
Penetrometer/Compaction Tester Reviews
1. BEST COMPACTION TESTER: AgraTronix 08180, Soil Compaction Tester
Two soil compaction testers make our top choice list for 2021; the best of which is this tester from AgraTronix.
With a maximum penetration depth of 24”, this unit has a very good testing range that will suit users at both the home and on the farm.
The 08180 features 3 testing range outputs; green, yellow, and red. Intuitively, green signifies good growing conditions and works at 0-200 psi.
The yellow range is 200 – 300 psi and signifies adequate growing conditions. Poor conditions are indicated within the red range at 300 psi and above.
Each of the color ranges is displayed via an easy-to-read, color-coded, stainless steel dial.
The importance of accurate soil testing is clear. Using one of these tools will help you better understand the quality of the soil in order to increase root and plant development, as well as calculate the correct application of fertilizers, pesticides, and herbicides.
Two tips are included with the tester; a ½” tip for firm soil and a ¾” tip for softer soil.
An adjustable shock collar is also provided in order to protect the main rod when not in use, or in transit.
The tester has a rubber grip handle for better traction and comfort.
Our top pick soil compaction tester for 2021 is this very reliable unit from Agratronix. With great testing depth, 3 output ranges that are clear and easy to understand, and a build quality that will mean this tool will last you a long time, there is a lot to like here.
Highly recommended for both garden and farm use.
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2. Dickey-John Soil Compaction Tester, Silver
Another good soil compaction tester currently available is this one from Dickey-John. In fact there is little in it between this and out top pick from Agratronix.
True the testing depth is greater here at 30”, however the price point is also higher.
In short, if you need extra capacity on the length of the testing rod, this is the model to go for.
The probe dial is not as simple to read as the 08180, however, the results are still well defined and will help you ascertain the health of the soil you are testing.
The pressure range is impressive at 0 – 500 psi, however considering the extra depth available here (30” against 24”), the extra psi reading ability is necessary.
Two tips are also available with the Dickey-John, again these are easily interchangeable depending on the soil hardness you are testing.
Another benefit of this soil compaction tester from Dickey John is the fact it is manufactured in the USA.
The company has a good reputation for its customer service, and if you have any issues with the product, it is good to know you can get a representative on the phone without too much trouble.
This may be useful in the case of this tester, as to be honest, the instructions are rather poor. The provided manual does not fully explain the testing procedure and how to best interpret the results.
That being said, resources are available online.
This soil compaction tester from Dickey-John is another good unit that will be especially useful for those that require as much testing depth as possible.
You will pay a premium for that extra depth, however. That being said, the fact this is a quality, well-made probe with a large testing range, means it still comes highly recommended.
3. Sensor-1 AGT-Soil Tester Soil Compaction Tester
The Sensor-1 AGT-SOIL TESTER Soil Compaction Tester is another option from AgraTronix, however, this model is more premium than our top pick and the price-point reflects that.
The unit has a 24″ steel probe and as with the other compaction testers reviewed here, comes complete with 2 different tips suitable for varying ground hardness.
The 1/2″ tip can be used on softer soils, while the 3/4″ tip is better suited to hard soil.
The Sensor-1 AFT is designed to measure soil compaction with readings at 3″ increments over the 24″ testing length.
The device also opts for a color-coded range indicator in line with the AgraTronix 08180. This is a yellow, green and red band range that indicates the varying levels of soil compaction.
The PSI test range is impressive, with 0 – 300psi capacity. The Sensor-1 is also very well made, the sturdy construction is both lightweights to use and carry around, while also exhibiting the robustness you need for a tool while out in the field.
This device is very closely matched to our number one pick from AgraTronix in terms of specifications. Again, this is a reliable unit that will get the job done.
However, it is worth noting the increased price-point for what amounts to a very similar performance.
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4. BEST POCKET PENETROMETER: AMS 59032 E-280
The first pocket soil penetrometer to make our top 5 list is also our favorite.
Balancing a budget price point with great features and most important of all accuracy is a measuring tool that will not disappoint.
Use it to conveniently measure the compressive strength of your soil on the garden or farm, the fact this can be stashed away in your pocket ready for use really is a major benefit.
This is a spring-operated penetrometer that has the capacity to push a ¼” diameter loading piston into the soil to the depth of .25”.
The readout is clear to understand. The compressive load of the soil (in tons per square foot or kg per square cm depending on your preferred metric) is indicated on the small reading scale located on the barrel of the penetrometer. The range is 0 to 4.5 tons.
Friction rings run along with the display and the result of the test is clearly indicated.
Build quality is good too. The manufacturers understand that this is a small tool that will potentially get knocked around while in use. This rugged pocket device is made from anodized aluminum and also comes with a small carry case that can be connected to your belt loop.
For convenience, the penetrometer can also be placed in your pocket as it only measures a mere 6 ¼” in length.
If you are looking for a budget-priced, reliable pocket soil penetrometer, your search ends here. This easy-to-read device, with spring-loaded action, is small and effective.
Just shoot the piston into the soil for an immediate understanding of the soil compaction levels. What more could you ask for?
5. Humboldt Pocket Soil Penetrometer, 0 to 4.5 Tons
The first of our penetrometers to have a maximum capacity of 4.5 tons per square inch is this impressive little offering from Humboldt.
This tool is larger than the pocket penetrometer that is our top pick this year, (the length comes in at 7 ¾”), the design is also more robust, opting for a stainless steel build.
However, Humboldt is a more premium brand in this space and the price-point does reflect that.
Back to the specifications, however. The core diameter is also larger in this unit when compared to the tool reviewed above. Measuring 2/3” instead of a quarter-inch, the spring-operated penetrometer will quickly and efficiently take the compressive soil strength of your plot.
This, of course, makes it ideal for garden, farm, or construction use, and as with any good pocket, a tool can be easily carried around on your person.
In this case, a small carry case with a belt loop is provided.
The readability of results is also important. Here, Humboldt has provided scale readings between 0 and 4.5 tons per square foot.
A great feature of the indicator is that the last reading will remain on the scale until you manually reset it.
If you are prepared to pay a little more for your pocket penetrometer, this is the unit that we recommend.
With a sturdy build quality and accurate testing function, this is a reliable device that won’t let you down.
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How to use a Soil Penetromater
The video above shows the basics of using a penetrometer to detect soil compaction. Posted by the University of Wisconsin-Madison, College of Agriculture and Life Sciences, this is a useful introduction that will help you understand the process in greater detail.
- “Modeling unconfined compressive strength of fine-grained soils: Application of pocket penetrometer for predicting soil strength” CATENA Volume 196, January 2021, https://doi.org/10.1016/j.catena.2020.104890
- “Diagnosing Soil Compaction Using a Penetrometer (Soil Compaction Tester)”, Penn State Extension [Download PDF]
- “Hand-Held Electronic Cone Penetrometers for Measuring Soil Strength”, United States Department of Agriculture [Download PDF]
- “Soil Penetrometer Fact Sheet”, Sustainable Agriculture Research & Education (SARE), [Download PDF]