Way back when, green-fingered gardeners tested their soil by – apart from look and feel – performing a ‘smell test’ and a ‘taste test.’
Chemistry has come a long way since then and soil testing kits enable even a greenhorn to know far more about his soil than those venerable old-timers could. A comprehensive soil testing kit will tell you your soil’s pH value, EC, TDS, moisture and temperature.
Soil testing probe-based meters are made by diverse makers with certain makers focussing on one or another aspect of soil testing and making single-purpose meters. However, all-in-one meters, of which three are reviewed underneath, are becoming increasingly popular.
What these soil testing meters should have in common – as many of them do – is durability, ruggedness, lightweight, and compact design: durable so they can do the job season after season, rugged so as to withstand knocks and mud, and lightweight and compact so that it can be taken from one end to the other of a large garden without any difficulty. The probes especially should be both strong and durable, yet sensitive.
Last update on 2021-04-12 / All Pricing & Imagery from Amazon Product Advertising API
Care for your meter and ensure long life and accuracy by not inserting the probes in waterlogged soil (let alone in water), not forcing them into hard or pebbly earth, and not letting them stay in the soil after you have taken your reading.
This high-end soil tester contains four functions and is as easy as pie to use and read
Morthan’s 4-in-1 Soil Tester includes metering and measuring for pH, moisture, temperature, and sunlight. It operates on a 9-volt battery. It is a variation of a common style of soil testing meter.
This kit is not only comprehensive, it is sensitive and well-gradated: it measures sunlight across a range of nine levels and pH across twelve.
Morthan’s digital kit gives quick readings. The LCD is large, clear, and bright enough to be readable in direct sunlight. However, its display of metered data is rather cluttered. To obtain a reading, the probe must be inserted about four inches deep.
Issues with accuracy and reliability in measuring soil moisture have been reported. Some units reportedly display a soil pH value about 1.5 steps above the actual value. Other evaluators have observed clearly inaccurate moisture readings. At the same time, the readings on many other units have been confirmed to be accurate. Therefore, we conclude that reports of these inaccuracies are not a systemic problem but defects in particular meters due to poor quality control. If you choose this Morthan product, what you get depends on the luck of the draw.
The non-adjustable 90-degree angle of the display means that in order to read it you have to lower your head so your eyes are nearly level with the readout – rather an inconvenient proposition when the display is about two feet from the ground!
At 32 x 6.3 x 3.6 centimetres and 200 grams this tester is not as small or light as others, but it is certainly not cumbersome or heavy.
This 4-in-1 unit, though it cannot be called expensive, is at the higher end of the range for this type of multi-function meter. Therefore, though it cannot be deemed value for money, it is our top pick because of its overall quality, being one of the best-in-class.
- Comprehensive soil testing meter measures four parameters across a wide range of levels.
- Very easy to use and provides quick readings.
- Among 4-in-1 soil testing meters, it is one of the best.
- Among 4-in-1 soil testing meters, it is at the higher end of the price range.
- Quality control problems result in dud meters being sold to buyers.
- The non-adjustable 90-degree angle of display sticking up two feet from the ground means you have to kneel . . . before a soil testing meter!
A single-function testing kit at a rock bottom price, Bornfeel 14-hue test strips provide an accurate and fun way to determine pH levels of soil and other semi-solids and liquids.
Bornfeel’s pH Test Strips indicate the pH value of soil and thus indicates its acidity or alkalinity level.
A simple test for a low, low price, these test strips are similar to the litmus paper that you used in Chemistry experiments in Standard IX. The difference is that litmus paper reacts with the liquid it is dipped in and will stay or turn red or blue with red indicating acidic and blue, alkaline. In marked contrast, pH strips change colour and adopt a specific hue, one of 14, so as to indicate an exact pH level.
As the pack has 480 strips you are guaranteed 480 test results for your money.
Obviously, because this test uses pH strips, you can use it to test the pH value of any liquid, fluid, or semi-solid – sweat, detergent, fruit, coffee, peanut butter, homemade pickle, and the bug-infested marshy ground down the lane are all candidates for pH measurement should you so choose. Inserting these strips into soil poses a challenge.
Virtually upon insertion or immersion, the strip changes hue ranging from crimson (1; entirely acidic) to chartreuse (7; neutral) through dark violet (14; entirely alkaline). A chart of hues keyed with numbers from 1 through 14 is included. As soon as you remove the strip from the tested substance, match its colour to the same or closest hue on the supplied chart to arrive at the pH level of your soil.
Some customers have complained that Bornfeel’s pH strips do not work at all but one must be mindful that the efficacy of such chemically-reactive substances expire within some time period whether or not such is specified. Also, storage in conditions of temperature extremes or high humidity can attenuate the reactivity of these strips.
The strips are of card that, compared to common litmus paper, is thick and substantial.
At the bargain-basement price, so many strips and so many readings – close to 500 – are an easy choice as our value pick. Ideal for gardeners who are interested mainly in their soil’s pH levels.
- So easy to understand, a child can use Bornfeel’s pH strips.
- Rock bottom price and so many strips represent terrific value for money.
- Provided the strips are fresh and stored in optimal conditions, you get accurate readings of pH levels.
- The only parameter you can measure with this ‘kit’ is pH levels.
- Difficult to insert into soil; do so by tying a strip to a prong or a twig.
- If you get a pack of strips that are more than a few years old, or that were stored in conditions of extreme temperatures or humidity, they will likely not work.
This four-function tester is compact and ultra-light but many units are erratic or defective
Cost: Price not available
ZhongYe’s 4-in-1 Soil Tester includes metering and measuring for pH, moisture, temperature, and sunlight. It operates on a 9-volt battery.
While this kit is self-evidently quite comprehensive, it is also sensitive and well-gradated. Like the Morthan product reviewed above, it measures sunlight to a spread of nine levels and pH to twelve.
This soil tester’s styling, design, functionality, and power-source range from similar to identical to that of the Morthan instrument, and so much so as to lead you to conclude that one is a knock-off of the other.
This digital tester’s LCD is bright and easy to read, and the rubber buttons are waterproof.
Insert the probe three to four inches into the soil to obtain a reading. Unfortunately, inaccurate readings and errors are known problems in ZhongYe’s soil tester. Some units report wet soil as ‘dry’ and direct sunlight as ‘low’ (light). Some other units display incorrect pH values. Such defective units are a serious concern.
This tester automatically turns off after five minutes of inactivity. This five-minute span of time is really good design because it is quite annoying when soil testers (or whatever other device) shuts off after a minute or two of inactivity and just before you are about to start using it again.
On the other hand, it is affected by a poor design common to soil testing meters. The non-adjustable 90-degree angle of the display means that you have to get your eyes nearly level with it which is worse than a nuisance when the display is less than a foot off the ground! Insert it at a 30-degree angle to make things less uncomfortable.
This tester is very compact with its dimensions of 12.2 x 6.2 x 3.6 centimetres. At a mere 70.6 grams, ZhongYe’s kit is the ‘lightweight champion.’
For a 4-in-1 digital soil tester, this ZhongYe product is so downright cheap that if it were not for concerns about its defective units and quality control, we may have chosen it as our value pick.
- Remarkably low price; unnoticeable to the pocket.
- One of the smallest and lightest 4-in-1 soil testing meters.
- Does not auto-shutoff too quickly – the five-minute auto-shutoff time is a very good design choice.
- Quite a number of units appear to be defective, giving erroneous readings.
- To ensure you have an accurate instrument, you would need to test it with control inputs or with inputs whose values are known in advance.
- The non-adjustable 90-degree angle of display sticking up a foot off the ground means you had better be skilled at doing the limbo.
A traditional analogue 3-in-1 soil testing meter, this easy-to-use product works right out of the box
-1 Soil Testing Kit is not really a product specific to Suplong; this one and the same 3-in-1 analogue meter is manufactured in a factory and branded and sold by various makers under their own brands and packaging, for example Atree, Alotpower, CityFarmer, and Zeemplify, with some, such as KKmall, both branding it under their own name as well as supplying it for other sellers to brand.
Unlike the other multi-function testers reviewed above this one is an analogue meter. It has two probes, one for pH and the other for moisture. Light is measured via a sensor. No battery is needed.
To operate it, set the 3-position switch to choose the appropriate test, insert probes 4 to 4-1/2 inches into the soil, and leave for about ten minutes. Then take your reading. The soil should not be dry nor very wet.
Because this is an analogue meter, it does not display stepped readings like digital meters; it indicates a point over a continuous range within its limits.
Like the digital testing meters reviewed above, this analogue instrument too is troubled by quality control let-downs as many units behave erratically or indicate outright wrong levels, sometimes of moisture and often of pH; however, it is likely that some of these complaints may be rooted in impatient gardeners not waiting for ten minutes to get an accurate reading.
It is fairly well built. The metering scale and its markings are somewhat cluttered, and the lettering and numbers are smallish so those with poor eyesight typically find it hard to take a reading.
The non-adjustable 90-degree angle of the display means that you have to get your eyes nearly level with it – rather uncomfortable when the display is a foot-and-change off the ground! Insert it at a 30-degree angle to make readings less uncomfortable.
Clear and complete instructions are included. At about 85 grams this unit is quite light.
A good choice for those who do not care to buy and rely on batteries and like the old-time charm of an analogue display and a continuous range of readings.
- Very easy to use and no battery required.
- Portable and very lightweight.
- As an analogue instrument it indicates values over a continuous range.
- Small type and cluttered display make readings hard to take for those with poor eyesight.
- Some units are erratic and inaccurate so try to test your unit using moisture, pH, etc. of known or guaranteed levels.
- The non-adjustable 90-degree angle of display sticking up a foot-and-change from the ground means you’ll need to “get down and dirty” – paging Little Mix…
Notwithstanding a somewhat involved procedure, Rapitest’s estimates of soil macronutrients are of immense value to the serious hobbyist
Cost: Price not available
This soil test kit is a very valuable addition to the gardener’s armoury because it is a highly technical test, being a TDS (Total Dissolved Solids) macronutrients test that measures the concentrations of Nitrogen, Phosphorous, and Potassium – N-P-K – in your soil. Therefore, Luster Leaf’s Rapitest does not compete with the multi-function soil testing meters reviewed above but complements them.
Rapitest has a total of 40 tests, ten each for Nitrogen, Phosphorous, Potassium, and pH.
The capsule-based N-P-K tests indicate an estimate in one of five levels: depleted, deficient, adequate, sufficient, and surplus. These are represented by different shades of the same colour.
The colour-coded pH tests span seven steps with five steps for acidic values and one value each for neutral and alkaline.
The testing procedure is neither easy nor straightforward. You need to take the soil sample from a specific depth as necessitated by the particular type of plants, mix soil and distilled water in the correct proportions, and shake it well.
Then you have to be patient enough to let it fully settle, and the time can range from 30 minutes to 24 hours, depending on the soil. Then this has to be transferred to the test chamber after which powder from the desired capsule is added.
Finally, the reacted solution has to be transferred via dropper into the comparator. It is self-evident that if the procedure is not precisely adhered to, one will get erroneous results or perhaps incomprehensible colour indicators.
We think that most reports of wrong results and general dissatisfaction with this kit arise from not meticulously following the instructions.
Pulling open the capsule and getting all the powder into the comparator is no easy feat.
Contains excellent instructions and also technically sound and useful information that is comprehensible to the layman. Includes a chart of pH and N-P-K levels for 100-plus plants.
Though Rapitest does not produce precise values, the estimates it indicates more than suffice for the hobbyist who is serious about gardening. For the kinds of soil information Rapitest provides at its price point, it is very good value.
- Although the testing procedure is involved and less than straightforward, a technical test for macronutrients is a boon for the gardener.
- In view of the kit’s price, the N-P-K estimates that it provides are good value for money.
- Packaged instructions and information are top-notch.
- Not exactly simple to twist and pull open the capsules and pour all the powder into the test chamber. It may be smart to use some alternative method.
- After you use up the sets of ten capsules, you are stuck with a useless bit of equipment because you cannot buy capsules separately.
- The testing procedure is tricky and complicated, and not adhering to it meticulously will bring about incorrect and unreliable test results.
Fundamental Soil Tests
Gardeners test soil for manifold reasons. The primary reason, as would be considered by most gardeners, is to measure the pH value of the soil. The runner-up reason surely is to determine the conductivity of the soil by way of its Electrical Conductivity (EC) and Total Dissolved Solids (TDS).
The pH value is measured on a scale from 1 through 14. Seven is neutral pH. Progressively lower numbers indicate greater acidity while progressively higher numbers indicate greater alkalinity.
The pH value is of use in determining which plants will thrive and which will struggle in your particular soil. Also, it is only when you know your soil’s pH value that you can decide whether to leave it as it is, acidify it, or alkalinise it as best suits your needs. Most plants are content in soil of pH between 6.0 and 7.5.
Soil EC determines the salinity of the soil as measured by the number of soluble ions of salt. The greater the ions of salt, the greater the soil’s conductivity. Excessive salinity damages the roots. Fertilizing the soil indirectly increases its salinity.
Soil TDS essentially indicates the level of nutrients already present in your soil. This information assists you in deciding whether or not to fertilize your soil and, if so, how much fertilizer to use. A more comprehensive TDS test is the macronutrient test that measures the individual nitrogen, phosphorous, and potassium in the soil. These N-P-K readings assist you in deciding which fertilizer to use, i.e. what its N-P-K balance should be. (In Chemistry and in the periodic table the letter ‘K’ stands for Potassium by virtue of this element’s Latin name, Kalium.)
Soil pH, EC, and TDS values are not independent of one another. They are inter-dependent, and one influences the level or extent of the other.
Other Tests for Soil – Hows and Whys
Soil pH, EC, TDS, and macronutrients are fundamental tests performed using soil testing kits. However, other tests are of value too. These include a feel test (texture test), drainage test, light test, and moisture test.
The Feel Test
The feel test, practised by gardeners through the centuries, involves collecting a handful of moist soil, squeezing it into a ball, and then evaluating it by trying to shape it into a ribbon.
Using this technique, you can estimate what mixture of sand, silt, loam, and/or clay your soil is composed of. A more involved method to determine soil composition has to do with putting a sample of soil in a jar, adding water, shaking it vigorously, and then letting it sit for two days so that the various components separate.
Soil Drainage Test
To do a drainage test, dig a hole twelve inches in diameter and one foot deep. Fill it with water and leave it overnight. The following day fill the hole with water once again. Stick a measuring tape into the hole so as to measure the level and drainage of the water. Make readings every hour. Two inches per hour is the optimum soil drainage rate but any mark between one and three inches an hour indicates good drainage.
Testing for light properly and rigorously is a lengthy and time-consuming process because it has to be done at different times of the day, and also during different periods of the year. The former exercise is to ascertain the mix of sun-shade your garden gets on a given day of the year, and the latter to determine the same for different days of the year. The test is done using a light meter (usually a function available in all-in-one soil testing kits). The light meter actually measures the intensity of light. The units of measure are lumens or lux (lumens per square meter). Normal light ranges from 500 to 1000 lux. You would need to prepare a chart or table of times of day and days of the year to get a true picture of the sunlight your plants get.
Soil Moisture Test
Testing soil moisture can seem like a futile activity – after all, you know when to water your plants, right? Not quite. The soil moisture test will tell you when your plants – each to its particular needs – require watering, and, therefore, if you do it often enough, you can develop a scientific schedule for watering your plants
Apart from telling you when to water your plants, the soil moisture test can also tell you if your soil is waterlogged or if you are watering too much, noting that over-watering can cause severe harm to your plant by causing root rot. Soil moisture can be measured using dedicated meters which may be analogue or digital, or with multi-function meters.
What Should You Look For In Healthy Soil?
Here are some interesting properties that will reveal the health – or lack thereof – of your soil.
Porosity is that property of soil that dictates and indicates how well the soil will hold water or how well it will drain it. Sandy soils have the most porosity and they will barely hold moisture, and water will drain very quickly. Clayey soils have the least porosity. Such soils, provided the clay is not compacted, will hold water to the extent of it being unhealthy for the roots, and will drain very slowly. Loamy soils of in-between porosity, the happy medium, are considered ideal. They hold water for sufficient time for the plant to feed but drain very well yet retain moisture.
Fresh Organic Material
Soil can ‘get jaded’; it can lose its nutrient content, and the reflex reaction is…fertilizing! However, soil can never get jaded as long as it has fresh organic material – the precursor of compost.
Simply scrape and scrabble with a trowel in your soil to check whether it has sufficient fresh organic material. If it does not, add compost. Little or no fresh organic material or compost is a sign of less-than-healthy soil.
Worms are a good indicator of healthy soil. When the soil temperature is 60 degrees Fahrenheit or more water it lightly so that it becomes moist. Then dig out the soil, stacking it on a piece of burlap, so that you make a hole about one foot in depth and one foot in diameter.
Examine the pile of soil with hands and fingers as you put it back in the hole, looking for worms. (Okay, we hear you going, “Yuck!”) If you count about ten worms, then your soil is healthy. Five or less means that your soil is lacking in the microbes and organic matter that worms need to survive and that are beneficial to your plant life.
Other properties of healthy soil that you should be aware of are that it should have little or no compaction, should not be over-fertilized and should be free of Roundup and other similar herbicides.
Kersie learnt the basics of gardening as a toddler, courtesy of his grandfather. In his youth he was an active gardener with a preference for flowering plants. He is a professional and vocational writer and his freelance projects have spanned various kinds of writing.