If you're serious about gardening, you probably know exactly what your plants need to thrive. Different plants grow well in different soils, temperatures, and humidity levels. But how can you be sure that your soil is right for your garden?
Simple: By using a soil test kit.
Soil test kits give you valuable information about the soil makeup of your garden. But different kits have different accuracy levels and available information.
We've compared many of the top soil testing kits on the market. These are our main recommendations.
Top 3: Best Soil Test Kits
Soil Moisture Meters
This is our top recommendation for a soil testing kit. It tells you all the important information you need to know about your soil's pH, phosphorous, potash, and nitrogen levels. The kit comes with everything you need to conduct the tests, including results cards that explain what your results mean.
The chemical testing setup is one of the simplest to use. You don't need to worry about mixing up different test components. The testing capsules are all color coded to the lid of their corresponding vial. Each color is used to test a different component of the soil.
There are ten capsules included for every one of the four tests, leading to 40 tests in total. This means that you can test several different soil samples at once, and you can keep doing tests to monitor your soil throughout the season.
Whether you're a seasoned expert or a beginner, the kit makes soil testing easy. Every package comes with detailed instructions that walk you through the process. There's even a list of several hundred plants and their preferred pH levels.
The nitrogen test will tell you about the nutrition of the soil. Nitrogen is the key nutrient needed for plants to grow. Because of how nitrogen is dispersed in the soil, it will be difficult to get an accurate reading, but you can get a basic estimate.
The phosphorous test will tell you about how fertile your plants will be. Good phosphorous levels lead to increased seeds and fruit. If you want a bountiful harvest, phosphorous is important. Just make sure you don't add too much, since the excess fruits might strain the plant.
The potash test will tell you about the strength of your plants. This component is used for plants to strengthen their stems, branch out their roots, and become resistant to the cold. Plants without adequate potash are more likely to wither and die in harsh conditions.
This testing kit is another one of the best options on the market. It is designed to teach beginners about how to read their soil results and adjust their soil makeup. For experts, the level of detail is super helpful.
The test will give you a full analysis of your soil's nutrition levels. Then you'll receive garden recommendations with specific actions you can take. Each test result includes fertilizer recommendations that use both synthetic and organic materials, so you can pick whichever one best suits your gardening taste.
Your report will tell you about a whopping 13 different soil components, including your acidity level and your nitrogen level. As with all tests, the nitrogen measurement might be inaccurate due to how soil is constructed.
The goal of the manufacturer is to encourage sustainable gardening. You can use this test kit on soil anywhere on your property. Whether you're analyzing your compost, garden, lawn, or the earth around a tree's roots, you'll get incredibly detailed information.
Every kit comes with all of the components necessary. These include return postage that's already been paid. You'll simply put your sample in the packaging and stick it in the mailbox. A lab will analyze the sample using precise measuring tools.
You also have access to a dedicated customer service team. If you have any questions about the soil collection process, concerns about your sample, or queries about your results, you can reach out to an expert.
When you purchase the kit, you'll make an online account with the company. This is where your results and recommendations will be uploaded. The kit itself comes with a soil measuring tool, sample jar, distilled water, and a capsule that absorbs the soil nutrients.
The return packaging is included for extra convenience. Instructions are easy to follow. You'll also receive professional guidelines on how to get the best sample, including information about why the accuracy range of different tests varies.
Your results will be shown in a bar graph form. This will tell you at a glance whether any of your components are outside the ideal range. You will also be able to access a personalized recommendation for fertilizers that will address any issues with your soil.
There are a few things that set this testing method apart from usual lab tests. In the end, you get a more accurate result than with similar lab procedures elsewhere.
The first important note is that the soil is not dried before being analyzed. With most other lab tests, the soil needs to be completely free of moisture before it is shipped. The components will also be ground into a fine powder to measure the nutrient percentages.
Doing these things alters the soil's integrity. Even though the nutrient profile is the same, there's no way of knowing whether the plants can access those nutrients.
With this testing kit, the capsule is dropped into normal moist soil. Instead of drying the components, the capsule moves through the soil and absorbs the important nutrients. When the scientists receive the testing package, they can observe the soil makeup in its natural state.
This testing kit can be used to measure the soil in indoor greenhouses, hydroponics setups, outdoor gardens, farmland, lawns, and other areas. It is designed to test the pH, moisture, and light levels of any given soil sample.
One important note is that the pH test needs to be done with wet soil. The sensor won't record the acidity if your soil is dry. It's important to water it prior to using the probes. Also note that you must use water to moisten it, as any other liquid will tamper with the results.
The soil meter tells you about everything you need to know with regards to watering your garden. By learning how much sunlight an area gets, how much moisture is in the soil, and how acidic the soil is, you get a sense of how much moisture your plants are absorbing per day.
The monitor uses a dual-needle system for increased accuracy. These needles will move to the corresponding result on the meter more quickly than most other probes.
Unlike digital testing devices, which require batteries, all you need to do with this is set the probes into the soil. Push them down anywhere from two to four inches. Toggle the testing switch. After that, the device will do all the work itself. You just have to watch the monitor readouts.
This test is easier to use than a chemical test. You don't need to harvest any samples or put together any complicated kits. You don't even need to worry about changing a device's batteries.
The manufacturer has engineered this device to be portable and lightweight. As such, you can take readings from multiple areas in your garden. Since analog sensors have a relatively wide margin of error, taking multiple readings will give you a better sense of your soil's average needs.
Keep in mind that while this will tell you a lot about your soil's water and acid needs, it won't tell you about the nutrients inside. If you want to learn about the nitrogen or phosphorous levels, you'll need to get a more advanced chemical testing kit.
There are many soil testing kits available to suit a variety of needs. Some will instantly tell you basic facts about your soil's nutrients. Some include detailed analysis by a lab. Some tell you about the moisture and sunlight levels, so you can adjust your garden watering schedule.
For overall testing quality, we recommend the Luster Leaf Rapitest. This kit comes with the necessary materials to conduct 40 tests. It's exceedingly easy to use, and it gives you the most important information about your garden soil. Just keep in mind that you won't get micronutrient readings.
If you're interested in a much more detailed panel of information, the MySoil kit is the best place to start. Your sample will be analyzed in a lab, and then you'll see your results for 13 different components. The company offers personalized recommendations for fertilizers and plant growth. It's also one of the most accurate lab testing options available.
For a basic test that tells you about your soil's moisture and pH content, we recommend the Sonkir device. This testing device doesn't require you to harvest samples or install batteries. You just stick the probes in the dirt. The product comes ready to use and has extremely simple instructions.
This will give you information about how much water your soil is retaining. However, it won't tell you about what nutrients or metals are present in the soil. If you're looking for a more detailed nutritional reading, you're better off with a chemical kit.
Frequently Asked Questions
There are a variety of reasons that someone might use a soil test kit. These kits are sometimes used to detect potentially hazardous materials in a patch of land. For gardeners, though, testing kits are more commonly used to assess their soil quality.
Plants need a delicate balance of nutrients to grow and thrive, similarly to people. When you buy fertilizer, it's generally enriched with these common components. Garden store soil tends to have phosphorous, calcium, potassium, and nitrogen in abundance.
If you're using the dirt in your backyard, or you're working with a new patch of soil, you should test it right away. This tells you exactly what type of soil you're using. It will give you valuable information about the types of plants that can thrive, and it will let you alter the soil to suit other plants too.
Testing is necessary to check whether your initial soil has the nutrients and makeup you need. If you don't test, you might be starting out at a disadvantage. Not only will fewer seeds propagate, but they won't grow as well or produce as much fruit.
You won't always need to add fertilizer to your base soil. Plants can actually be harmed by too much fertilizer, as the excess nutrients lead to erratic growth. For example, the roots of overfertilized carrots tend to fork into multiple tips.
It's also important to find out the pH level of the soil. Different plants need different acidity levels. If your soil is too alkaline or acidic for a certain plant, your sprouts might not take root. Most common garden plants require a neutral acidic range.
Macronutrient testing is a way of testing your base soil and your fertilizer to see the nutritional balances.
Store-bought fertilizer will usually come with an NPK rating on the label. This tells you about the balance of the specific nutrients nitrogen, phosphorous, and potassium. But before you purchase fertilizer, you need to know what nutrients your base soil lacks - if any.
A variety of tests are available to measure nutrient levels in the soil. These might show varying accuracy with potassium and phosphorous, but it's difficult to find an accurate nitrogen test.
This is because nitrogen tends to move around the soil. Instead of being spread evenly throughout the particles, it tends to clump in patches. In addition, plants use it primarily to grow their leaves and stems. You'll have a hard time gauging how much nitrogen your plants have already soaked up, and how much they will soak up in the future.
Nitrogen is such a finicky element to test that even professional testing facilities struggle to get an accurate reading.
Phosphorous is responsible for helping flowers and fruit grow. If you're growing produce like cucumbers or tomatoes, you need an abundance of this element. Keep in mind that excess phosphorous can lead to excess flowers. Though the blooms are pretty, the plant may become overstressed when it creates fruit.
Potassium is responsible for helping the plant's roots develop. If a plant wants to branch out and take root in deeper soil, it needs potassium. Inadequate potassium leads to small roots, which prevents the plant from getting enough nutrients to grow.
If a plant has too much potassium, it can cause misshapen and erratic roots to grow. That's not a problem in most cases. But if you're growing carrots and other root produce, you'll want to keep the potassium levels steady. Otherwise, your produce will be seemingly mutated when you pull it out of the ground.
Macronutrient testing looks for the levels of the three most important nutrients for plant growth. But a lot of home kits don't measure any nutrients beyond these three. And yet plants need nutrients like iron, magnesium, zinc, and calcium.
A micronutrient test can look for other nutrient levels in the soil. The exact nutrients being tested for will vary depending on the kit.
In addition, micronutrient tests might be used to look for potentially toxic materials. They can detect the presence of sulfates and lead. If you do have heavy metals in your base soil, they can leech into your plants. That won't necessarily kill your garden, but it can be dangerous if you intend to eat any of your garden's produce.
For this reason, you should always get a comprehensive micronutrient panel that screens for heavy metals before you start gardening in a new area.
The pH level of your soil measures how acidic or alkaline it is. The majority of plants prefer a neutral soil balance, meaning somewhere between acid and alkaline. However, there are some that need more acidic balances.
It's important to know the ideal pH level of the soil for whatever plants you plan to grow. Once you know about the level of your base soil, you can either adjust the acidity or leave it as is.
The accuracy of pH testing varies because different patches of soil might have different chemical makeups. However, you can get a basic sense of the garden. If you have a large garden area, you might want to take samples and readings from multiple areas and compare the results.
There are a variety of ways to alter the pH level of your soil. Most can be done without investing in any expensive gardening products. For example, adding calcium or lime can have an immediate effect. Keep testing the soil until it has the range you're looking for.
In the past, farmers didn't have advanced measuring tools to analyze their soil. Instead, they had to determine the acidity levels by tasting it. A sweet-tasting soil was closer to alkaline, while a sour one was closer to acid.
The struggle of this testing method, obviously, is that the tester had to eat dirt. Today's methods are much simpler!
There are a few different kinds of testers that are calibrated in different ways. For some, all you'll need to do is put the testing stick in the ground. It will then mark the acidity level on a scale.
You can also use a chemical testing kit. This is a little more involved than simply putting a probe in the dirt. Each kit will come with instructions from the manufacturer. For the most part, you'll follow these steps:
The sensor will then analyze the components of the soil.
Some pH testing units are built with analog or digital faces. These also commonly test other factors like moisture, macronutrients, and even sunlight exposure. So it's important to make sure that you've calibrated the device to the right test.
Once you're on the pH testing screen, put the digital tester in the soil. The manufacturer will tell you how deeply you need to bury it. If the device uses an LED display, you'll probably have your results in around 60 seconds. Gauge testers aren't quite so speedy, but they tend to show results in about ten minutes.
The testing device itself might come in a variety of different designs. There are three main design types for soil testing:
Each type of tester has advantages and disadvantages. The accuracy levels depend more on the components being tested than on the tester's design. For example, as mentioned, nitrogen readings tend to be spotty in accuracy because of how nitrogen is distributed in the soil.
In addition, if you're concerned about the accuracy of a home testing kit, you can seek out the services of professional soil testers. These people might come to your property to measure your soil's data, or you might send them a sample through the mail.
Chemical testers follow a straightforward procedure. You just put some of the soil you're testing into a tube included in the kit. Then you add water to the fill line. The final step is to drop a colored capsule inside, which releases the testing material.
If your kit is meant to test for several nutrients, there will be a different tube included for every one. The capsules will correspond to the color of the lid. This makes it easy to keep the matching components straight, so your results remain accurate.
Once the water, testing agent, and soil are all inside the vial, you'll shake it. The instructions should tell you how long to wait. After the allotted time has gone by, you can compare the color of the water to a nutrient or acidity chart.
There are also more advanced chemical kits. These might ask you to add a few drops of chemical testing liquid by using a vial, rather than dropping in a capsule. If you do use one of these, it should come with detailed instructions and a wide range of testing options.
Chemical tests don't have the highest accuracy possible. However, they usually give you a ballpark estimate on the level of your soil. As mentioned, you can also test multiple parts of your garden and average the results.
A chemical test kit is limited to however many vials and capsules are included. Once you've used all the capsules, it's important to dispose of your kit. If you reuse the vials, the plastic might age and degrade, which interferes with the results of the test. Old vials might also be contaminated with previous materials.
Digital testers use probes that you stick into the ground. Because these testers tend to run using electricity, you'll need a battery. Some kits come with the batteries included, while others don't.
Before using digital testers, you should clean every probe with water and soap or rubbing alcohol. This disinfects the probe and removes any potential bacteria or contamination. You should do the same thing after you finish doing your soil test.
Keeping the probe clean allows you to reuse the soil tester multiple times. If you want to take several readings in your garden, a digital probe is one of the most economical options.
There are some digital kits with advanced cleaning solutions included. These are typically part of testing protocols made for professional gardeners, landscapers, greenhouse owners, and other growing industries. The cleaner removes every soil particle from the surface to guarantee accuracy in the next test.
Some digital testing kits will include vials instead of probes. With these, you'll combine water and your soil sample into the tube. Some options require you to add a chemical agent, while others don't.
When you do use a digital kit that includes water mixing, you should use distilled liquid. Since distilled water has been purified of minerals, it's less likely to interfere with the nutrient readings. The fewer minerals your water has, the more accurate the reading will be.
Digital kits are primarily used to analyze pH levels. When you're looking for macronutrient or micronutrient information, you'll probably need to use chemical kits instead.
Analog testers are testing devices that use several metal probes. You push these into the soil in a natural formation. This leads to a natural connection of electric energy. In turn, this allows the testers to sense certain soil components without being hooked to an outside electrical source.
Since the testers are not powered with outside electricity, you don't have to worry about installing batteries. At the same time, they use the same electrical sensors that you'll often find with digital probes.
The majority of analog testers can estimate the pH level of the soil, though the degree of accuracy varies. They can also estimate how much sunlight is penetrating the soil when the test occurs. Finally, they'll tell you about the moisture level of the soil.
More rarely, an analog test might tell you about the soil's fertility levels. This analysis is done broadly and doesn't include more specific information about the levels of different nutrients.
Analog testers have a somewhat lower accuracy rating than digital ones. However, if you just need a quick read on your soil, these are a simple option. It's best to test multiple areas and look at the average of your results. The probes must be cleaned between every use.
Because of how simple the design is, an analog tester can't be used to gather extremely detailed data. However, it can give you a basic sense of how your soil has changed between the seasons, what the acidity level is, and how much moisture is in the ground.
If you're testing your soil prior to planting, you'll want more detailed information than an analog kit can give you. But an analog kit might be sufficient to monitor acid and moisture levels as your plants grow throughout the seasons.
Professional soil testing is the best way to get an accurate reading on the acidity and nutrients in your soil. Soil samples are processed in a lab, where scientists use multiple scientific instruments to measure their contents.
Some professional services may come to your property and harvest your soil samples for you. With most, though, you'll need to harvest the samples yourself and mail them according to the company protocols.
To get the best soil sample for your garden:
Once you've done this, you can either mail it to the lab or bring it there in person.
At the lab, the sample will undergo several tests. Laboratory testing gives a much more accurate assessment of your phosphorous and potassium levels. In addition, labs can look for certain micronutrients that aren't covered in the majority of mainstream chemical kits.
Some micronutrients that labs can measure include:
There is some margin of error in micronutrient tests. That's related less to the sophistication of the testing tools and more to the finicky nature of the soil. Many nutrients and chemicals tend to clump together and move around, which means it's difficult to tell how present they are through a single sample.
One thing to keep in mind is that if plants have already taken root in your garden, the soil around them will likely have fewer nutrients than non-rooted soil. The root systems of your plants will consume the nutrients around them for growth.
Lab testing for nitrogen is particularly inaccurate because of this. You will get a reading on exactly how much nitrogen is in your soil sample. But there's no way to guarantee that this reading remains consistent throughout your yard. Even if you have samples from multiple areas, the clumping nature of nitrogen makes it hard to measure.
If you do have your soil professionally tested, the testing team can give you personalized recommendations for your soil. You'll tell them about the plants you want to grow, and they'll tell you about the nutrients and minerals you should add.
Another thing that professionals do, which you can't get in an at-home test kit, is analyze the soil makeup. You'll find out how much clay, silt, sand, and organic matter makes up the soil. This will help you determine what components need to be added for a balanced environment.
Professional testing has by far the most detailed and accurate results. You can get data about a ton of different nutrients and soil factors. However, you'll also need to be patient. Sometimes the results can take several weeks to come in. So if you're impatient to start gardening, a chemical kit is a better bet.
Some educational institutions and agricultural centers will offer free testing. Students use this service to learn more about how to analyze soil samples. Depending on where you are, you might be able to get a soil sample container from the library.
If you do this, you'll then read the instructions in the container. These will tell you how to curate and mix your sample. After you've done that, you can drop the container off wherever the testing is done.
You're more likely to have easily-accessible soil testing services if you live near an agricultural college or on farmland. Many farmers need to test their soil frequently, so free services give students an excellent chance to practice.
With that said, not every agricultural school or center will test your soil for free. It will depend on your area. You'll need to explore the resources around you and find out what kind of professional soil testing options there are.
Some agricultural colleges have almost free testing. Basically, you just need to cover the cost of shipping and the cost of the chemicals used to test. This tends to be significantly less than at a for-profit lab. It's also a great value considering how much accurate information and insight you receive at once.
A test you make at home won't be as accurate as one you purchase. However, you can get a basic sense of the acidity level by making an at-home test. In addition to the soil sample, you'll need these items:
That's it. You can probably do the test with ingredients you already have in your cupboard.
Make sure the containers are clean before you use them, as any particles might interfere with your testing accuracy.
Once you have all of your items, follow these steps:
Acid soil needs alkaline components to reach a neutral state. Alkaline soil needs acidic components.
If you don't see fizzing or bubbling from either container, then your soil is neutral.
This test doesn't tell you your exact acidity levels. It won't guarantee that you're in the right range for your plants to thrive. But it will give you a good sense of where to start when altering your soil content.