How to Test Your Soil
Your soil’s health is what determines the overall health of your grass and other plants. When you work from the ground up, you are ensuring superior grass quality. Fertilizing your lawn regularly is good practice to make sure your grass is getting nutrients, but what if you aren’t sure which exact nutrients your lawn needs at the time?
For example, you may be applying an abundance of nitrogen, but you aren’t really seeing a difference in your grass’s appearance or quality. You might also notice that grass isn’t growing as well in some areas of your lawn as others, but you aren’t sure why.
The best way to diagnose a problem before spending time and money on other solutions is to collect and submit a soil analysis in your yard. A soil analysis will inform you of all the nutrients you need in your lawn.
What is a soil test?
A soil test is a tool that can be used to determine which macro and micronutrients are currently in your soil and which nutrients your lawn and garden needs to reach its optimum pH level. Most of the time, companies will make suggestions on how to improve your soil’s quality with fertilizers or other amendments based on the results from the soil test.
Soil tests can come in different shapes and sizes, but they all require you to collect a sample of soil from your lawn and place it in some sort of small container or baggie to submit to an expert. Whether you mail a package in or drop it off at your local cooperative extension office depends on the company or turfgrass expert you go with.
Why should I use a soil test?
A soil test is an inexpensive way to see what your soil needs to perform its best. A soil analysis essentially measures the pH of your soil and provides nutrient recommendations to achieve optimum performance.
Regularly applying fertilizer products and other chemicals can impact the pH levels of your soil, so collecting and submitting a soil sample provides information about which nutrients your lawn needs or doesn’t need.
For example, if you’re looking at purchasing a nitrogen fertilizer, a soil sample might come back and say there’s already more than enough nitrogen in the ground already. Your lawn may need other nutrients to excel instead.
A pro to this is that you won’t waste money on fertilizers your lawn and garden don’t need. After soil test results recommend solutions, the fertilizer chemicals will be absorbed into the plant and won’t sit in the soil. Over-applied fertilizers that don’t get absorbed typically get washed away with the rain into streams and other natural bodies of water, which is harmful to the environment.
A soil test will tell you exactly what the soil needs so that you can make an educated decision on which fertilizer or nutrients to purchase.
By improving the environment your lawn and garden grows in, you’re essentially working from the ground up to improve your lawn and garden’s health. With that being said, there are different soil types depending on where you live. Each soil type tends to have different pH levels.
How do I collect and submit a soil analysis?
This often depends on the company you’re submitting the soil test to. Sometimes they’ll want you to place the soil in a container they mail to your address. Other times, they’ll provide you with instructions for collecting the sample and placing it in a container or baggie of your own.
If you’re collecting a soil sample and placing it in your own container (not one provided to you by a professional) it’s important that you collect the sample in a container that won’t affect the pH levels of your soil. Plastic containers like a bucket or baggies are usually the best options—not metal.
You should always follow the instructions each company or cooperative extension office provides you with when collecting and submitting a soil sample. However, it’s often recommended you collect soil samples from various locations throughout your yard and then combine them into one collective soil sample.
Soil samples have the ability to widely vary in different locations in your yard—even if it’s just a few feet away from the site another soil sample came from. Collecting from different areas of the lawn reduces any inconsistencies from the different locations in your lawn and allows the soil sample to test a larger area.
Instructions for collecting a soil sample
1. You’ll start by collecting several soil samples in plastic probes or baggies. Make sure they’re thoroughly cleaned before use so they don’t contaminate your sample.
2. Walk in a zigzag pattern as you collect the samples. Most universities and landscape professionals recommend collecting soil from about 10–15 locations. Use a shovel or soil probe like the ones listed below to collect the samples. Each sample should remove soil from the top 6 inches from the soil’s surface.
3. Afterwards, remove any plant material, mulch or natural soil organisms like worms and drop the soil samples into a plastic bucket. Mix the samples well to make sure it’s blended.
4. Dump the soil out on a newspaper or grocery bag and then allow it to dry. Wet soil may alter the soil analysis, so make sure it’s dry before collecting.
5. Once dry, you’ll want to collect about 1 pint of the soil to send to your turfgrass expert.
Areas in the lawn, vegetable garden, ornamental beds or problem areas should all be tested separately. Be sure to remove any plants or mulch from the sample.
When is the best time to collect and submit a soil analysis?
The best time to collect and submit a lawn soil analysis ultimately depends on where you live and what type of grass you have. The best time to soil test a warm season grasses such as zoysia, St. Augustine, bermuda grass and centipede grass should ideally be collected in the spring. This generally takes place between March 15th and April 30th.
Soil tests for cool season grasses like Kentucky bluegrass and fescues should be collected between August and September.
Generally speaking, the best time to collect soil samples from gardens or ornamental beds is during the fall. You can then make amendments before winter so that they can take effect in the spring.
One of the best times to conduct a sod analysis is when you are about to install new sod because it allows you to see what nutrients you need after the installation process is finished. This will help you get your lawn off to a healthier start. Be sure to collect a soil sample before applying chemicals like glyphosate to kill off old grass as this can alter your lawn soil test.
However, it is never a bad idea to conduct a soil analysis if you need to see what nutrients your lawn or garden needs.
How often should I test my soil?
Most lawn and garden professionals recommend testing your soil once every 1–3 years. Some experts suggest once every 3–5 years. We believe submitting soil samples are invaluable ways to keep your lawn and garden healthy—it also rarely costs a lot of money. Unless there are problems occurring in your lawn and garden, we suggest submitting a soil sample once every 1–3 years. If problems arise like poorly performing turfgrass or ornamentals, you should send a soil sample in right away.
Who do I send a soil test to?
There are many different professionals you can send a soil sample to. Most of them can be divided into two groups: 1) a local cooperative extension office, or 2) a company you bought a soil test kit from and mail it back to.
1. A Local Cooperative Extension Office
Each state has its own soil testing cooperative extension office you can either drop your sample off at or mail it in to. Find your local cooperative extension office here.
Be sure to visit the local cooperative extension office’s website and follow soil testing instructions thoroughly. Many of these websites have a soil testing form you can print off and fill out to send with the sample.
2. A Company You Bought a Soil Test Kit From
Another option is to buy a soil test kit from a company and submit it back to them in the mail. If this is what you’re looking to do, some of these companies will still have someone who can professionally test your soil sample and provide you with accurate results and recommendations. Just be sure to do your research on what they can offer you.
Depending on the company you go with, their results forms might also be easier to read and comprehend.
One of our favorite companies for soil samples is Soil Kit. Soil Kit performs this service for the homeowner with an inexpensive, user-friendly and quick soil test system providing easy-to-understand recommendations for correcting soil and nutrient deficiencies.
The analysis is done by a leading national laboratory and the recommendations are ready in 7–10 days. The lab tests for pH and includes the amount of phosphorus, potassium, magnesium, calcium, boron, zinc, manganese and iron in the soil. These are presented in a low, medium, adequate and high graphic range analysis to support the recommendations for corrective nutrient action by the homeowner.
Most importantly, the recommendations are tailored to your location, time of year, size of lawn or garden, type of crop or grass and presented in precise product and quantity recommendations.
Soil Kit is easy to use. Simply follow the directions on the bag and on our Soil Kit website:
1. Register your kit on soilkit.com.
2. Collect soil from four areas of your lawn or garden and place it in the test bag.
3. Mail in the sample bag in the postage-paid mailer.
4. Our leading national agricultural lab will test your soil with in-depth analysis.
5. Results are easy to understand and recommendations are delivered to you in your soilkit.com dashboard via email.
6. Take your report back to the store and know that you will return home with exactly what your lawn needs without more chemicals that might damage your lawn or the environment.
How much do soil samples cost?
The amount a soil test costs depends on who you choose to do the soil analysis. Universities generally charge between $10–$15 while it can vary for companies. Some cost about $12 while others can run up to $40.
How long does it take to receive my soil testing results?
When you submit your analysis to a local cooperative extension office, the soil analysis takes between 3–4 days usually. During heavy sampling times like April or May, it might take as long as 1–2 weeks.
How do I read a soil analysis?
Soil test results come in all kinds of different forms. Generally speaking, you’ll receive a sheet of paper or a digital report that will provide you with information on which nutrients your soil is lacking and which nutrients your soil is plentiful with.
Some soil tests will give you a simple N-P-K analysis (nitrogen, phosphorus, potassium) while others might go into more detail.
In general, most soil analyses will provide you with your soil’s results compared to what the optimal results should be. Ratings may include an analysis for your pH levels, nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B) and lime and fertility requirements.
pH levels range from 1 to 14 with 1 being very acidic, 14 as very alkaline and 7 as neutral. Your soil’s pH depends on your soil type, however, your lawn and garden are more receptive to absorbing nutrients at a pH rating between 6.0–7.0.
Oftentimes, homeowners over-apply nitrogen fertilizers and other macronutrients (N, P, K) without also including the proper amount of micronutrients (S, Ca, Mg, Na, Fe, Mn, Zn, Cu, B). Although they’re micronutrients, they’re essential to your lawn and garden’s health and can make a huge difference.
Another key nutrient that often plays an underdog in lawn and garden nutrition is carbon. Along with nitrogen and oxygen, carbon is one of the essential building blocks of all organic life. In fact, 50 percent of a plant is made up of carbon. Like plants and animals, soil is also carbon-based and needs carbon, nitrogen and oxygen to remain balanced and healthy.
How do I improve my soil after a soil analysis?
Soil analysis solutions can vary. Some soil testing results will come with suggestions for products that will help your lawn and garden. If they don’t, you’ll need to know how to read a fertilizer label so that you can choose the best fertilizer for your soil.
Alkaline soils will need nutrients to make it slightly more acidic so that it reaches the 6.0–7.0 pH range. On the other hand, acidic soils will need nutrients that make it more alkaline.
Sod University recommends the Lawnifi® Fertilizer Annual Subscription program. Lawnifi, a cutting-edge fertilizer, reduces the age-old problems associated with ionic nutrient lockup. Powered by Catalyst TechnologyTM, Lawnifi nano-sizes its nutrients so that more of them are absorbed through the roots and leaves of plants.
As a result, larger amounts of nutrients are efficiently delivered to plants. The amount of product that needs to be applied is significantly reduced while using 80 percent less nitrogen and yielding better results.
With less nitrogen usage, Lawnifi fertilizers work to balance C:N ratios in your soil for optimum soil and microbial health.
Ultimately, soil tests are invaluable tools that will provide you with a lot of information as to how you can improve your lawn and garden’s health. Most of the time, they’re also inexpensive.
Editor's Note: This article appears courtesy of Sod university. Check out more Sod University tips here and subscribe to their weekly newsletter.