Plants need light, oxygen, water, and a growing medium that meets their nutritional needs. Commercial and natural fertilizers can provide essential nutrients that soil may lack, but to get the correct type of fertilizer, the gardener should first know the condition of the existing soil.
Testing garden soil is the best way to determine what it needs—if anything—and how much. Soil testers and test kits range from simple pH strips to complex chemicals that pinpoint deficiencies. The best soil test kit to help achieve one gardener’s goals may not be the best for another because various kits offer different kinds of results.
Read on for shopping tips and find out why these kits are trusted to identify essential nutrients lacking in your soil.
- BEST OVERALL: MySoil – Soil Test Kit
- RUNNER UP: Soil Savvy – Soil Test Kit
- BEST BUDGET: Atree Soil pH Meter
- TRADITIONAL PICK: Garden Tutor Soil pH Test Strips Kit
- BEST CHEMICAL TEST: Luster Leaf 1662 Professional Soil Kit
- BEST DIGITAL TEST: Luster Leaf 1605 Digital Soil Test Kit
- BEST FOR CROPS: Whitetail Institute Laboratory Soil Test Kit
- BEST FOR PRECISION: Bluelab PENSOILPH pH Pen
- ALSO CONSIDER: Kensizer Soil Tester
What to Consider When Choosing the Best Soil Test Kit
Many gardeners and home landscapers buy fertilizer and soil amendment products that promise to produce robust plant growth, improve soil structure, or result in abundant blooms. Still, unless the products provide what the soil lacks, the results may not be what the gardener expected. In some cases—like adding fertilizer to nutrient-dense soil—plants may even suffer from fertilizer burn. Soil testing takes the guesswork out of gardening and landscaping.
Soil quality varies from location to location. The soil in some regions might be perfect for growing vegetables and flowers, while the soil someplace else must be heavily amended with organic matter to grow anything. The following four common types of soil have different properties:
- Silt: Fine and soft, silt grains are smaller than grains of sand. Silty soil is associated with prior flooding that washed topsoil downstream. Silty soils are suitable for growing most types of plants but will benefit from adding organic matter to help increase drainage. Depending on its nutrient content, it may also require fertilizer.
- Loamy: An optimal blend of silt, sand, clay, and organic matter, loamy soil is a gardener’s best friend. It drains well, yet resists compaction as it dries out. It’s suitable for growing fruits, vegetables, and most types of flowers and shrubs.
- Clay: While clay soil is full of nutrients, it’s composed of ultra-fine particles that stick together when wet and become rock-hard when dry. Plants don’t grow well in clay soil because their roots can’t push as easily through thick clay as they can with other soil types. Clay soil must be amended with organic matter, such as compost, to help aerate the soil and make it suitable for growing plants.
- Sandy: Better than clay because it offers spaces between the grains for roots to grow, but not as nutrient-dense as loam, sandy soil drains well. It is suitable for growing bulbs, such as tulips, and root crops, including potatoes and carrots. When preparing soil for the upcoming growing season, adding organic matter will help it retain moisture when growing other types of plants.
Several soil-testing products are available to determine the amounts of different nutrients and macronutrients in the soil. Among the most comprehensive tests are those that involve taking soil samples and sending them to a lab for analysis. Still, at-home kits and instruments like these can be of help.
- Strips: A simple type of soil test, pH strips are coated bits of paper that determine the current acidity or alkalinity level of the soil. The gardener mixes soil with distilled water, using the recommended ratio on the package instructions. (Tap water can influence the pH readout.) After inserting the test strip in the solution, the resulting color of the strip lets the gardener know whether the soil in the garden is acidic or alkaline. A chart usually comes with pH test strips so users can compare the colors.
- Analog: These testers are commonly used to test soil for moisture content, pH levels, and some may even test the quality of the light in specific locations. They feature aluminum probes to be inserted in the soil when taking readings. Some may use batteries, but many analog testers react to wetness in the ground and often don’t need batteries.
- Digital: Like analog soil testers, digital soil testers often come with probes to insert in the ground to determine moisture content and pH levels. They usually require batteries and may also be used in conjunction with chemical testing to help determine nutrient levels, such as the amount of nitrogen or potash in the soil.
- Chemical: At-home chemical soil tests require adding a drop or two of a specific chemical called a “reagent” to a soil sample. The reaction helps show the health of the soil. Chemical soil tests are suitable for testing one or more factors, including pH, and specific nutrients, such as nitrogen or calcium.
- Professional: The most reliable of all soil tests, professional tests require the gardener to collect a soil sample. The sample is mailed to a laboratory, where it’s analyzed for structure and a variety of nutrients. Then the lab sends the results and soil recommendations back to the gardener.
Testing kits and instruments commonly help pinpoint soil characteristics. Knowing the makeup of the soil helps you better maintain your garden. Keep in mind that different plants prefer specific nutrients over others, so it’s essential to research the plant that will be grown before adding nutrients.
- Macronutrients: The three most common macronutrients needed for healthy plant growth are nitrogen (N), phosphorus (P), and potassium (K). Every bag of fertilizer will list an NPK number that identifies the amount of these three nutrients. The types of N, P, and K nutrients come in various forms, such as potassium carbonate for potash, and urea or anhydrous ammonia for nitrogen. In general, all the NPK varieties perform similar functions. The key is knowing which specific nutrient that a plant needs and then using the soil test results to add a fertilizer formulation that helps balance nutrient levels.
- Micronutrients: Plants may require trace minerals as well as macronutrients, and a soil tester that pinpoints micronutrients, such as copper, iron, and manganese, tells the gardener if too much or not enough of these nutrients are in the soil.
- Acid or alkaline: The pH scale runs from 0 to 14, with 7 being considered neutral. Most garden plants prefer slightly acidic soil, between 6 and 7. However, some plants such as lilac and clematis prefer slightly alkaline soils, while azalea prefer acidic conditions.
- Temperature: Testing soil temperature is much like testing human temperature; the tester has a thermometer that indicates how warm or cool the soil is. This is helpful for commercial growers who want to start production as early in the spring as possible. It also can be helpful for hobby gardeners who want to make sure the soil is warm enough before they set out seedlings.
- Light: Because plants need various amounts of light, a light meter can help determine whether a location will be optimal for a specific plant variety. While plants have different light needs, all need some light for photosynthesis, which is how the plant synthesizes water and carbon dioxide into food. Most at-home light meters will display low, medium, and high lighting conditions. A gardener can use these readings to determine whether a plant is receiving enough light (or too much light) in a specific spot.
- Moisture: One of the most common soil tests is for moisture, and it’s used to determine whether the soil is draining well. Moisture meters usually have a gauge that allows the gardener to see if the soil is dry, moist, or wet.
Soil test kits vary in accuracy, with professional lab tests ranking the most accurate of all. The quality and composition of the soil may also vary from one end of the garden to the other based on the amount of light that a specific spot gets, whether leaves fall and decompose in one spot, or what types of plants were grown there in the past. For example, plants in the legume family, such as soybeans or clover, can add nitrogen to the soil.
Choosing the most accurate test or tester can prove challenging, but look for things such as large, easy-to-read gauges on analog testers and probes that are solidly attached. Chemical kits should offer multiple testing processes for double-checking results, and pH test strips will be most accurate before their expiration date. No matter the individual test kit, gardeners can help avoid mistakes by performing multiple tests in different spots.
Speed of Results
The quickest results come from tests that determine pH and moisture. At-home test kits and instruments can determine these two factors in mere seconds. Testing for other nutrients may take longer, especially if the soil has to be combined with water and then allowed to settle before performing a chemical test. Light and moisture meters can often determine results in a few minutes. Retesting can be done as often as desired to get an idea of light quality during different times of the day and to see whether moisture evaporates more quickly from soil during higher outdoor temps.
The longest wait period comes when seeking professional laboratory results. The gardener must gather the soil samples, place them in a package, and mail the package to the laboratory. Depending on the speed of the lab, it may take a few days to test the sample and then a few extra days to get the results. Some labs can send results by email, which speeds up the process by a couple of days.
Ease of Use
Test kits that feature pH strips and meters with probes are simple to use and self-explanatory for the most part, but the best soil test kits come with directions on how to handle the strips and the probes, in addition to offering information for understanding the relevance of the test results.
Chemical test kits can be more complex, but they come with instructions on gathering soil samples, mixing them, and choosing the chemicals to use when conducting specific nutrient tests. Chemical kits will often come with charts that explain what the different results mean, such as various color changes that occur when testing for particular macronutrients and micronutrients.
Our Top Picks
To qualify as a top pick, a soil test kit must offer consistent and reliable results. Test kits and testing equipment vary by the type of test being performed, so some will be better suited to home gardeners while others may appeal to commercial and agricultural growers. The following soil test kits are some of the best in their specific testing categories.
For ease in testing and reliable professional results, consider MySoil’s offering. This kit allows gardeners to gather samples of soil and have them professionally tested for a range of nutrients as well as pH level. For those who want an in-depth analysis plus custom soil amendment recommendations, the MySoil kit reveals amounts of micronutrients, NPK, and macronutrients.
After receiving the test kit, users register online, then add soil to the provided testing cup and drop the pre-addressed return package in the mail. Results are available online within 8 to 10 days.
- Measures 13 plant nutrient levels
- Can test any environment or garden
- Comes with full instructions
- More expensive than other options available
- Results in 8-10 days
If you’d like to receive custom fertilizer recommendations for your garden, check out this option from Soil Savvy, which allows users to collect a soil sample and have it professionally analyzed. The kit comes with a scoop, a collection cup, a prepaid postage envelope, and complete instructions on collecting and submitting a soil sample.
The lab will analyze the soil for a wide range of macronutrients and micronutrients. It offers recommendations through email and on the manufacturer’s website on how to amend the soil, if necessary. The lab will also recommend specific NPK fertilizer ratios for applying fertilizers to achieve optimal nutrition levels.
- Tests for pH and moisture content
- Results in 10 minutes
- Built-in light sensor for testing light conditions
- Measures less plant nutrients than other comparable tests
To monitor pH and moisture levels in the soil and determine whether certain spots in the garden are receiving adequate sunlight, try Atree’s multipurpose tester. It has an analog scale, never needs a battery, and comes in at an affordable price point.
The Atree tester boasts two probes—one for detecting the soil’s pH and the other for determining its moisture content. A simple switch on the front of the meter allows the user to switch back and forth between the results.
Users can also choose to test the quality of the light conditions via a built-in light sensor on the meter’s face. The probe is inserted into the soil and left in place for 10 minutes to get the most accurate readings.
- Measures 14 plant nutrients and pH balance
- Comes with instructions for sampling
- Offers fertilizer recommendations through email
For simple pH soil testing, Garden Tutor’s test strips offer quick and accurate results in determining the acid/alkaline content of indoor or outdoor soil. The kit contains 100 test strips, so gardeners can monitor pH levels in multiple garden areas on an ongoing basis. It also includes a 16-page handbook that lists optimal pH levels for growing various plants, including turfgrass and specific flowering plants.
Testing involves collecting a soil sample, mixing it with water, and then dipping a Garden Tutor test strip in the mixture. Depending on the pH level, the pads on the test strip will change color. A chart is included so users can match the colors on the test strip to the coordinating pH levels.
- Analyzes pH balance for soil optimization
- 100 pH tests included
- 16-page testing handbook included
- Does not test for fertilization or other plant nutrition levels
In addition to determining the pH level of soil, Luster Leaf’s kit pinpoints the amount of the three most common soil macronutrients: nitrogen (N), phosphorus (P), and potassium (K). With this chemical test, there’s no need for the user to send a sample to a laboratory.
The kit provides for 80 tests: 20 each for soil pH and each of the NPK nutrients. With the results, growers can choose the best fertilizer formulation for the specific types of plants being grown. Complete testing instructions are included, and buyers also receive tips for amending the soil and altering its nutritional content.
- 80 tests included
- Specializes in measuring nitrogen, phosphorus, and potassium
- Instructions for testing included with kit
- Tips for proper fertilizing included
- More expensive than comparable options
- Less tests included compared to other at-home kits
Luster Leaf’s digital tester provides quick and easy-to-read readings of your soil’s pH and NPK levels. Users collect a dry soil sample, mix it with water, add a drop of the included reagent, and then pour the mixture into a small test tube. The tube then inserts into the test case. Once the test tube is in the case, the user can choose to view a breakdown for nitrogen (N), phosphorus (P), and potash (K) levels on a scale that shows whether there is a surplus of the nutrient, a sufficient or adequate amount, or whether the soil is deficient.
The soil’s pH level is also shown. In addition, an included booklet has suggestions for amending soil and a list of soil preferences for more than 450 different types of plants.
- LED light technology reveals results in seconds
- Performs 25 tests; 10 for pH and 5 for nitrogen, phosphorus, and potash
- Included informational guide for 450 plant types
- More expensive than some other testing kits
Hobby farmers and crop growers can receive an expert soil analysis with this soil test kit from the Whitetail Institute. After taking soil samples from the plot, the user combines the samples and sends them to Whitetail Institute’s lab for testing. As a part of the submission process, the user also lists the type of crop that will be grown. The lab results and specific recommendations for improving the soil to boost the crop are available within 1 week, by email or snail mail, making this soil test a benefit for large-scale growers who want to ensure a successful harvest.
- Measures for phosphorus, potassium, calcium, and magnesium
- Recommendations provided for lime and fertilizer
- Suitable for large-scale growers
- Results in 1 week via email
For commercial-scale growers, hydroponic growers, or gardeners who want the ultimate in precision pH testing, consider the Bluelab pH pen that provides highly accurate acid/alkaline results. The pen comes with a backlit LCD display that makes seeing the readings easy, and it features two-point calibration (calibration solution included) for ensuring accurate pH readings. The pen requires a AAA battery for operation, and it features a lab-quality glass probe.
In addition to testing soil, users can test hydroponic growing mediums, such as coconut coir. It can also be used to test the pH of any liquid, including the water in a pond or pool, and it measures temperature as well.
- LCD display and 2-point calibration for precise pH readings
- Provides accurate acid, alkaline, and coconut coir measurements
- Can be used for ponds and pools to measure pH balances
- Includes required AAA battery
- Expensive compared to other options
Kensizer’s soil tester eliminates accidental overwatering and lets the user know if the soil is draining adequately. This battery-free tester is always ready to go and features double probes, one for testing pH and the other for testing moisture levels. It also has a light sensor for determining the quality of light that the plant is receiving.
A handy three-way switch allows the user to switch between tests and read the results on the same analog gauge. The tester comes with a large dial face and a color-coded scale to help the user see at a glance if the moisture, pH, and light readings are within normal ranges for growing healthy plants.
- 3-in-1 device; determines pH level, sun exposure, and moisture content
- Results in 10 minutes
- Does not require batteries
- Lightweight; can be used indoors and outdoors
- Does not test for fertilizers or other plant nutrients
Testing kits that identify pH balance, moisture levels, and light exposure with fast results stood out as most efficient. The MySoil test kit takes care of diverse plant needs in this way and makes recommendations specific to your plants’ indoor or outdoor conditions. The Atree soil tester provides these crucial readings on a budget, without soil-specific recommendations—if that compromise suits you, it’s a great testing alternative.
How We Chose the Best Soil Test Kits
After conducting research on the best soil test kits available today, the above picks reflect the easiest to use, most reliable and versatile choices for your garden. Many of the above options are also lab tests or home test kits which provide different levels of accuracy and advice.
For example, the home testing kits above mainly focus on testing for pH balances, light exposure, and moisture levels. Whereas all of the lab test kits from our top picks can test for nutrients and fertilizers for growing plants including phosphorus, potassium, macro and micronutrients, and acid/alkaline.
But, both types of testing kits provide accurate, fast, and easy-to-understand results, all while being hassle-free. Above all, these selected picks for the best soil test kit measure your soil with different needs and preferences in mind for a flourishing garden, house plant, or potted plant.
FAQs About Soil Test Kits
The best soil test kit can help a gardener figure out the most beneficial fertilizers or amendments to add to a garden. Below are answers to some common questions about soil testing kits.
Q. Why do I need to test soil?
If plants are thriving, there’s no need to test the soil. However, if plants seem to wilt, die, or just do poorly, testing the soil could help determine if the problem is due to a structure or nutrient deficiency in the soil.
Q. Can I test my own soil?
Absolutely. Many DIY-type soil testers are available for testing everything from moisture and pH to the amount and type of nutrients in the soil.
Q. Are digital soil testers accurate?
Digital soil testers are usually reasonably accurate. Gardeners can increase accuracy by performing multiple tests in different spots of the garden and comparing the results.
Q. What are the soil-testing methods?
Soil test kits feature pH strips, analog or digital meters, and chemical testing. Professional testing is available by sending soil samples to a lab.
Q. What does a pH test measure?
A pH test measures the acidity and alkalinity levels of the soil.
Q. How do I adjust the pH level of my soil?
Soil treatments are available that will either raise or lower the soil’s pH level, depending on what the gardener is growing. These are often called pH-UP and pH-DOWN products.
Q. Do soil test kits expire?
Kits with pH strips may expire in a few months, especially if they’re not kept in an airtight container. Meters and monitors will not expire. However, if they’re battery operated, they will require new batteries when the old ones run down. Chemical kits are often good for 2 to 5 years.
Why Trust Bob Vila
Bob Vila has been America’s Handyman since 1979. As the host of beloved and groundbreaking TV series, including This Old House and Bob Vila’s Home Again, he popularized and became synonymous with “do it yourself” home improvement.
Over the course of his decades-long career, Bob Vila has helped millions of people build, renovate, repair, and live better each day—a tradition that continues today with expert yet accessible home advice. The Bob Vila team distills need-to-know information into project tutorials, maintenance guides, tool 101s, and more. These home and garden experts then thoroughly research, vet, and recommend products that support homeowners, renters, DIYers, and professionals in their to-do lists.
Glenda Taylor is a freelance writer for the residential remodeling, homebuilding, and commercial roofing industries. She and her husband have been general contractors for over 20 years, and Ms. Taylor has written for leading media outlets, including the Houston Chronicle, SFGate, and the eHow Now Live Handyman Channel (a division of eHow.com) as well as National Association of Homebuilders. In addition to her construction experience, Ms. Taylor is a Master Gardener, a former real estate professional, a universal design enthusiast, and an advocate for green building practices. The recipient of Journalism and Marketing degrees from the University of Kansas and Bauder College respectively, she enjoys life on a farm in the Midwest with her husband and their five Saint Bernards!