Soil Testing 101: What You Need To Know For a Flourishing Garden
Good soil equals good plants. Regular soil testing helps you better understand your soil and how you can improve it.
Seeds are cool and bulbs are special, but the real core of a successful garden is healthy soil. Great garden soil is what makes plants thrive. If you are starting a new garden or have issues with your current plants, it may be time to test your soil.
Think about how a plant grows - its roots dig deep into the soil for water and nutrients. Soil is made of living and non-living materials and nutrients. If the soil lacks nutrients, your plants won’t grow well. When the acidity level of the soil is too high or too low, plants can’t uptake the nutrients they require. A soil test is a terrific diagnostic tool and will give you the information you need to correct issues.
If you aren’t sure how to test soil, you’re not alone. It’s a lot easier than you might think. Read on to learn more about soil testing.
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Why Is Soil Testing Important?
When your doctor wants to check your health, she orders blood testing. Think of a soil test as the equivalent for your soil. It is a sort of diagnostic that reveals many things about your soil: its composition, its pH, its nutrients - or lack of nutrients. It can tell you if the soil needs fertilizer - but also if it has been over-fertilized. It can identify soil-borne pathogens.
A soil test should evaluate many aspects of your soil. It can tell you whether your soil is sand, silt, or clay, and check its pH level. It will check available nutrients too. This includes calcium, magnesium, phosphorus, and potassium.
Once you get the soil test kit results, you can figure out why a crop is not doing well, and, generally, diagnose plant issues. Regular testing allows you to understand your soil and how you can improve it. It is a must if your crops are ailing, but also important when you are installing a new garden.
When to Test Soil
The best times to test your soil are spring or fall. Either one will set you up for a productive season, but fall is more convenient since you can get results and amend your soil before spring planting.
Do you have to do it every year? You do not need to retest the same soil year after year. Instead, test the soil pH and nutrient status every three years or so. But if you want to start a new garden, test the soil before planting.
Home Soil Tests vs. Lab Tests
There are two options when it comes to soil testing: home tests and professional testing. Home soil tests are usually less expensive and their results are almost immediate. But if you send soil samples to a lab for testing, the results will be more accurate and complete.
If you are a homeowner that simply wants to know the pH of the soil, a home test like this one from Amazon is probably sufficient. You can also get a digital 4-in-1 soil meter to measure soil moisture, pH, temperature and sunlight.
Which way to go? It depends on what you need to know. If you are only interested in the acidity of the soil, a soil acid test kit you do yourself is probably just fine. But when you are concerned about nutritional deficiencies or diseases in your soil, it’s probably worth it to send the test to a lab. Look for professional testing through your local county extension office, since it is usually free or low-cost. You can also get a mail-in soil test kit from Amazon.
How to Test Soil
Whether you decide to use a home test kit or take the soil in for lab testing, you’ll still need to gather a sample. You may wish to take soil samples from around your garden, rather than only one location to get an idea of the composition of your entire garden.
If you are putting in a new garden, you might be better off gathering samples from the one area of the landscape.
If you have a soil sampling probe like this one from Amazon, so much the better, but if not, a spade will suffice. (Don’t use galvanized steel however, since it can skew the results.) Here’s how to proceed:
- Clear the top of the soil where you wish to take a sample. Scrape away any debris or weeds.
- Use a garden tool to cut straight into the soil at least 6 inches (15cm) deep. Make another cut to create a V-shaped hole.
- Cut a slice of the soil as long as the hole. Take it from one side of the hole. Then cut a strip from the center of this slice. Take from that strip a cupful of soil.
- Bring that cup of soil indoors to dry.
- Place the sample in a plastic bag, seal it, then label it with your identifying information on it. You should also label it with the date and area from where it’s been collected; like “veggie garden” or “front lawn”.
- Take the soil sample to the lab or mail it in.
- Review your results.
Understanding Your Soil Test Results
The lab will send you back the results of your soil test. They may have a written recommendation of what type of amendment to use or just the pH and the levels of nutrients found.
The soil test will also list your soil’s pH for each sample. A pH of 6.0-7.0 is perfect for growing veggies so if you are within that range, you need do nothing. Otherwise, pH varies for different crops. If you wish to grow a crop that prefers a higher pH (alkaline) add lime, if your crop of choice prefers a more acidic pH, add sulfur. You can get both lime and sulfur from Amazon. Keep in mind that raising or lowering pH levels isn’t an overnight fix. It can take a year or longer to shift that pH.
As far as information regarding the levels of nutrients in your soil, the lab will be focusing on phosphorus, potassium, magnesium and calcium. Nitrogen is, of course, extremely important to plants, but it is malleable in the soil making it difficult to precisely test for.
If you are having difficulty interpreting your soil test results, reach out to your local extension office or even local chapter of Master Gardeners.
Soil Testing Essentials
Get the perfect soil sample every time with this sampler probe kit. The probe comes with a cleaning brush and soil sample baggies.
Send your soil sample away for lab results that are available through an app. They provide recommendations to improve your soil health, too.
A great option for home testing. This kit tests for Nitrogen, Potassium, and Phosphorous levels as well as the pH of your soil. Quick and easy!
Frequently Asked Questions
How can I test my soil myself?
You can buy a simple home test soil kit, or a digital 4-in-1 soil meter to measure soil moisture, pH, temperature and sunlight.
Simpler still, is to test soil by feel. Squeeze some soil in your hand, then open your hand and shake the soil a bit. If the soil stays together in clumps, it’s good soil. If it falls apart or slips through your fingers, it’s sandy or poor soil. Clay soil will stay in the form of your clenched fist.
What is the most accurate way to test soil?
The most accurate method is by sampling the soil and sending it to a reputable lab to be tested.
How Often Should You Test Your Soil?
Soil should be tested every 3-5 years in established gardens. New gardens should be tested before planting so any necessary amendments can be worked into the soil. Sample fields at the same time each year.
Are home soil test kits accurate?
Home soil test kits have their place but they are not as accurate as a lab soil test. They won’t give you as much information either. You can get a mail-in soil test kit from Amazon.
