The Best Soil Test Kits Will Help You Grow Your Perfect Garden

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If you want your plants to grow big and healthy, soil quality matters. Even if you aren’t planning on growing a lush veggie garden, all plants need nutrients to grow, in addition to light and water. Even if you believe you have generally “good” soil, there may still be room for improvement. Without testing the soil, you won’t know what specific nutrients your soil has in abundance, and which ones your plants still need.

Soil test kits are the easiest and most accurate way to cut out your indecision and figure out exactly what kinds of nutrients your plants and soil need. Testing your soil using a kit is simple and easy. With the best soil test kits, you can find out what your soil has enough of and what you may need to supplement to grow a stellar garden this year.

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The Best Soil Test Kits

What to Consider When Buying Soil Test Kits

What Do Soil Kits Test Do?

Though they come in many forms, soil test kits check your garden for nutrients and other things that plants need to grow, including pH levels, moisture, and sunlight. Gardening tool manufacturers broadly refer to these desirable elements as “components.” Most test kits give you the ability to test for many components at once. Here are some of the most common things gardeners track using soil test kits:

Nutrients: Plants need nutritious soil to grow, so many soil test kits focus on checking nutrient levels in the ground. Most look for “macronutrients,” which plants need most, such as potassium and nitrogen. Many also test for micronutrients like iron and zinc, which plants need in small quantities, but are still essential for growing a lush garden.

At-home kits that test for nutrients usually focus on a core set of macronutrient tests. Lab-based “professional” kits, which ask you to send a soil sample to a company lab, test for a much wider range of micronutrients. Some kits will also detect complementary components, such as organic matter and carbon, which don’t directly help plants grow but may impact the nutrient retention of the soil.

pH Level: Checking the pH level of the soil will reveal how alkaline or acidic it is. Most plants prefer neutral soil–a pH of 7–but your ideal results may vary depending on what you hope to grow. Some plants and trees, such as lavender and ornamental cherry trees, prefer slightly alkaline soil. Others, such as blueberry bushes and dogwood trees, prefer more acidic soil.

Temperature: Checking the temperature of your soil helps you determine the best time to plant new seeds. If you’re unsure if it’s warm enough to plant yet, it’s a valuable feature to have.

Light: Not every soil test kit will measure light, but it’s valuable if you want to figure out whether a plant will receive low, medium, or full sunlight in a specific spot.

Moisture: Some soil test kits will also test the moisture of the soil, although of course, this can change with rain or watering. However, measuring moisture content according to the instructions on the test kit may help determine how well the soil retains moisture.

Testing Format

Soil test kits come in a variety of formats. Different types are better suited for specific types of soil. In addition, some gardeners have a preference for analog or digital tests.

Paper strips: Paper, the simplest test in the kit, is usually reserved specifically for pH tests. To use one, you mix some soil with water, then dip the paper strip into the mixture, which will cause it to change color depending on the pH level. (Don’t worry, the test will come with a chart so you can check the results.)

Chemical: Chemical soil tests allow you to test for nutrients and check your soil’s pH level at the same time using water and a reagent. Simply mix a small amount of soil with a solution and wait for it to change color, revealing what nutrients are present.

Some chemical kits come with digital readers, which tell you results without the need to check color-coding legend and give more precise pH test results. These tests tend to be more expensive, but you can reuse them many times and streamline the testing process.

Analog: Analog test probes allow you to quickly test pH, moisture, and light levels by simply sticking a small metal spike in the ground. They only test a limited number of components, and cannot test your soil for nutrients, but they provide readings very quickly. Since analog testers don’t require a disposable chemical element or batteries, they’re also the most sustainable and long-lasting option in this group.

Professional: Some test kits also give you the option to collect a soil sample and ship it to a lab for professional testing. As you might expect, these tests offer the most information–including pH, nutrients, and carbon exchange capacity. They also tend to be more accurate than any of the at-home test kits.

Test Accuracy

The precision of soil tests can vary from kit to kit. The best way to ensure an accurate test is to rely on a lab-based test. That said, lab tests take longer and cost more, so they may not always be the best option. If you’re using an at-home test, I recommend taking multiple readings in different parts of your garden so you can see how conditions vary and get average results for your whole plot.

All that said, there are a few things you can do to make sure you get the most accurate reading with an at-home test:

• Check the expiration date of the test

• Verify whether the kit allows for multiple testings to double-check results

• Follow the testing instructions closely

• Test multiple areas of soil

Getting Results

The amount of time each soil test takes to present results varies from kit to kit as well. Chemical tests and paper strip tests require anywhere from a few minutes for results to up to 24 hours for the solution to sit. Analog and digital tests may be quicker, but can take up to a few minutes. The longest, of course, is a lab test, which typically takes at least a week.

Regardless of how you test, be patient and make sure to follow the instructions for the most accurate results. If a kit says to leave the solution for 20 minutes, set a timer. After 30 minutes, the results may not be precise.

How We Evaluated the Best Soil Test Kits

I relied on a mix of personal testing and research to select the best soil test kits. I personally tested many of these selections in my own garden. Those that I couldn’t test personally were evaluated based on their features and user reviews from Amazon and other retailers.

Soil Test Kit

This professional testing kit from MySoil allows you to collect a soil sample at home and mail it to a professional lab with a prepaid mailing package that uploads results to an app in about 6-8 business days.

Though it takes a long time, you can measure the pH of your soil and check for 12 other nutrients, including nitrogen, calcium, zinc, iron, potassium, phosphorus, magnesium, sodium, manganese, sulfur, copper, and boron with a single test.

One thing to keep in mind: MySoil uses a phone app to deliver your test results. There’s no way to access results without using the app. Also, the kit only contains a single test, so you need to buy multiple kits to test different gardens or areas of your yard.

1602 Soil Test Kit

This paper strip kit from Luster Leaf comes with 20 tests, which will check the pH of your soil along with its nitrogen, phosphorus, and potassium content. (There are also larger kits with 25 or 40 tests.)

The number of tests allows you to test multiple beds or areas to get an accurate read on your nutrient levels. It also means that you can test the soil before and after adding nutrients to make sure your levels look good over time.

One thing to note: The pH test will present results in just a few minutes, but the nutrient test requires 24 hours to get a proper reading.

Soil Tester

Although this soil tester from Kensizer doesn’t measure the nutrient content of the soil, it can read the pH and moisture content in your soil quickly. The results show up in about 1 minute, so you can get in there and start gardening right away.

Since it’s an analog tester, the test is reusable and doesn’t require batteries to run. You can use it whenever you want, on as many sites as you want. (Just make sure to wipe the probes clean after each use.)

One downside to this kit, beyond not capturing nutrient data, is that it does not measure sunlight. (Many analog tests measure sunlight, in addition to pH and moisture.) That said, it’s very inexpensive and easy to use, which makes it a fine addition to any gardener’s toolbox.

Soil pH Meter

If you need to measure pH, moisture, and light, this probe from Sonkir is a nice, affordable option. Like our pH test pick, reusable, easy-to-use and doesn’t require batteries. Analog tests, generally, are the most portable, which makes them perfect for testing indoor and outdoor plants.

Though it performs an extra test and costs slightly less than my pH test pick, the Sonkir takes substantially longer to run–about 10 minutes. It isn’t as if 10 minutes is a particularly long time, but you may prefer the faster read if you aren’t planting new seeds.

Soil Test Kit

If you’re looking for a more comprehensive testing kit that includes both nutrient and pH testing, this kit includes everything you need to test 13 different nutrients in the soil, as well as pH levels. Like my top pick, Soil Savvy is a lab-based test, so you get accurate results, but the test costs more and takes seven to 10 days.

Plus, the report offers fertilizer recommendations based on your results to help you know what to do next. It’s a slow but thorough test, which is perfect if you need someone to tell you exactly what your soil needs to support healthy plants.

1665 Soil Test Kit

This chemical testing kit from Luster Leaf comes with 50 sets of four tests–pH, nitrogen, potassium, and phosphate–making it the perfect option for anyone who needs to test many plots over a long span of time. With this many tests, you can check multiple spots in a few gardens on a regular basis over the course of a growing season.

The tests show results in just a few minutes, so there’s no waiting for a lab result to come back. It also comes with a handy portable carrying case, so you don’t need to find a place to store everything, and it’s easy to bring the tests from garden to garden.

1605 Digital Soil Test Kit

This battery-powered chemical soil tester from Luster Leaf makes testing the pH, nitrogen, potassium, and phosphorus content of the soil very simple. Just mix dirt with purified water in a test tube and add the capsule that contains the reagent. Place the test tube into the slot on the digital reader and press the corresponding button for the component you want to test.

Unlike standard chemical tests, this test gives you clear results that you can read without a color-coding chart. Misreading a chart at the end of a test can easily lead you to add too much or too little fertilizer to your soil, which may hurt your garden, rather than help.

The system isn’t perfect. The reader is reusable, but only comes with 25 reagent capsules. Technically you can buy additional capsules through the LusterLeaf website, but you have to fill out a form and pay by check or money order.

I also found that the test vials are small, which can make it challenging to add the reagent. Still, the Luster Leaf 1605 Digital test is fast, accurate, and takes the headache out of reading test results.

Soil Test Kit

Like the other lab-based testing kits on this list, SoilKit can check for a variety of nutrients and other components, such as potassium and phosphorus. It gets extra credit, however, because it includes tests for a few components that most kits don’t check for, such as buffer pH, organic matter, and carbon exchange capacity (CEC) in your soil.

A Buffer pH test measures your soil’s “residual acidity,” which can specifically be neutralized by lime. It gives you a more specific recommendation for whether you should add lime to your soil and, if so, how much.

Carbon exchange capacity testing measures your soil’s capacity to store nutrients, indicating whether it’s a good or bad place to grow plants. In soil with low CEC, you will likely need to add more nutrients and test frequently to grow a full garden, as the soil will not hold its nutrients for very long.

Lastly, an organic matter test measures plant residues, living biomass, fecal matter, and decaying organisms (such as dead bugs). Like CEC testing, an organic matter test can help you gauge the fertility of your soil.

If you are starting from square one in a new garden, this test can help you figure out if your soil is ready for gardening. You’ll not only see what nutrients are in the soil, but get an overall read on the condition of the ground.

Q+A With Gardening Expert Jenn Ryan

PM: Can I test multiple areas with one kit?

JR: Aside from lab-based tests, which rely on a single sample, most soil test kits give you enough material to test multiple areas with a single kit. With some tests, like paper strips, that means using multiple single-use tests. Others, like analog and digital tests, are reusable so you can test as often as you like.

PM: Are soil test kits only for outdoor use?

JR: Most soil test kits work for both soil beds outside and potted soil inside. Specifically, analog, digital, chemical, and paper strip tests all work well on indoor and outdoor soil. In most cases, it doesn’t make sense to use a lab-based test on potting soil. All that said, be sure to read the instructions on whatever kit you buy, as it should tell you specifically whether or not the test is made for potting soil.

PM: When should I test my outdoor soil?

JR: I recommend testing in early spring, after the last risk of frost has passed, and in the fall, before the first frost sets in. If you’re using a professional test, make sure to get it in as early as possible, especially in spring. There’s usually a surge of tests at the start of growing season, which may lead to delays at the lab.

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