Why, When, and How to Test the Soil pH of Your Lawn

soil test

Lawn soil can be acidic, alkaline, or neutral. This particular quality is measured in pH levels, and it’s quite important to your turf’s health – or any plant’s health, for that matter. From time to time, it’s important to test your soil’s pH levels to make sure that it’s in the right range. But how do you test it? We’ll show you why, when and how to test the soil pH of your lawn easily and effectively.

Why Should You Test Your Lawn’s Soil pH?

What is soil pH? Soil pH is a way to measure acidity or alkalinity, be it lawn or garden soil. It is measured in pH units on a scale from 0 to 14. Extreme acidity is at the low end of the scale, while extreme alkalinity is at the top end. Lawn soil pH at the midpoint (7.0) is neutral soil – neither acidic nor alkaline.

Jim Friedericks
Jim Friedericks

Most lawns and turfgrasses thrive at a pH range of between 6.0 and 7.0. Soil pH affects plant growth, and important nutrients for plants tend to be available in soil when the pH is at those levels.

“With a very low pH there are risks of toxicity for aluminum and manganese as well as interactions between elements that reduce the availability as well,” says Jim Friedericks, Director of Outreach and Education at AgSource Laboratories. Highly acidic soil also can directly damage roots.

When Should You Test Your Soil?

Soil pH Update

It’s possible to soil test your lawn at any point in the year as long as your soil’s conditions are right. However, the best time to test your soil’s pH is in spring or early fall, before you’ve added any compost, fertilizer, or soil amendments to your lawn. This way, you get a clear picture of what your soil is actually like – deficiencies and all.

Generally, experts recommend testing your soil every three to four years. However, you may have to test your lawn’s soil more often depending on how your turf is doing. If your lawn is struggling, you may want to conduct a soil test to help narrow down what the cause could be.

You also should test your soil yearly if you’ve applied soil amendments to your lawn. The change in soil pH caused by amendments tends to take effect very slowly. For example, it could take a year or more to see the results of a lime application. You’ll want to test your soil to keep track of these changes over time.

How to Test Your Soil pH

There are two approaches to testing your soil pH: DIY testing with an at-home kit and professional testing at a soil testing lab. Let’s take a look at their advantages and disadvantages in the tables below:

DIY Soil Testing Kit
✓ Convenient to use
✓ Gives results within an hour
✓ Inexpensive
✓ May also tell you if your nitrogen, phosphorus, and potassium levels are low, normal, or high
✗ Can be inaccurate
✗ Won’t tell you how to fix your soil
Professional Soil Testing
✓ Can tell you your soil’s pH
✓ Can tell your soil’s nutrient levels
✓ Gives precise and detailed results
✓ Will recommend soil amendment and fertilizer to fix soil issues
✓ Reasonably affordable
✗ Not as convenient
✗ Can be costly if you need to do multiple tests
✗ Can take weeks before you get your results

While DIY testing with a soil pH meter or pH test strip is convenient, fast, and cheap, it can give you misleading results. Numbers matter when it comes to the pH of your soil, and even a slight difference on the pH scale can mean a big change to your lawn’s acidity. If you’re willing to take the risk, you can pick up an at-home soil testing kit from your local garden center or home improvement store.

If you want precise results and recommendations on how to improve your soil, then sending soil samples to a laboratory is the way to go. The only sacrifices you have to make are the extra cost and the added wait. While you can’t speed up time, there is a solution if you’re worried about the price tag: contacting your local Cooperative Extension Office.

Nearly all Cooperative Extension Service offices offer low-cost soil testing services. Check with your local Cooperative Extension Office for details on how to take a soil sample and where to send it for a pH test. They can help you find a testing service that is familiar with your particular locale or send it for testing through their office. Just make sure to use the same lab every time you test your soil as different labs have different tests.

Decided on what method you’ll use to test your soil pH? We’ll teach you how to actually accomplish it.

Sending a Soil Sample to a Lab

While it sounds straightforward, sending your soil to a lab for testing isn’t as simple as digging up soil and shipping it in the mail. The soil has to be properly handled, and it can’t be any ol’ soil in your lawn. While the specifics of taking soil samples will vary from lab to lab, the general process is quite similar. Here’s how to collect a soil sample to send to a lab in five easy steps:

  1. Make a map.
  2. Clear organic matter.
  3. Dig.
  4. Take more samples.
  5. Prepare the final sample.

But first, you’ll need the following materials:

  • Plastic Bucket: Galvanized buckets can contaminate the soil sample.
  • Shovel: Make sure it’s clean and has no rust.
  • Hand Trowel: Make sure it’s clean and has no rust.
  • Plastic Container or Baggie: Prepare this if your lab didn’t send you a container for the soil sample(s).
  • Newspaper

1. Make a map.

You’ll need to collect about 10 to 15 samples from your lawn to mix into a final sample that accurately represents your lawn. You’ll want to take samples in areas that are relatively the same in terms of environment. Don’t add soil that’s near a body of water, for example. You also don’t want to mix in soil from your vegetable garden, flowers, and other ornamental plants.

Do your best to take your samples from areas without fertilization or chemicals; although ideally, you should be testing before you’ve added anything to your lawn.

Take your samples in a way that makes you go through your lawn in a zigzag pattern to make sure you’re taking soil throughout your lawn evenly.

2. Clear organic matter.

Remove or set aside any thatch and growing or dead plants from your digging area. You don’t want any organic matter in your soil sample.

3. Dig.

Photo credit: Eerik / Canva Pro / License

Using your shovel, dig a hole about 6 to 12 inches deep; usually, soil labs recommend 6 inches if you’re sampling for a lawn. Dig straight down if you can. Cut a ½-inch thick slice from the sides of the hole.

If you see any organic matter, like more thatch and worms, then remove them. Place the soil in your bucket.

4. Take more samples.

Repeat steps 2 and 3 for every dig site. You should end up with a generous amount of soil in your bucket.

5. Prepare the final sample.

Use your trowel to mix up the dirt in the bucket, removing any rocks and crushing clumps until you have relatively smooth soil. Then, take 1 to 2 cups of soil and let it air dry on the newspaper. Make sure it doesn’t get wet.

Once it’s dry, place the soil in the plastic bag or container. This will be your final sample. Follow the lab’s instructions to mail them in. 

Testing With an At-Home Soil Testing Kit

At-home test kits vary hugely, so it’s absolutely critical to follow your chosen test’s instructions. The test kits can be as simple as a pH test you used in high school all the way to multiple tests with various chemicals. Be sure to pick up some distilled water because most soil test kits require it. 

Here is how to test your soil’s pH using a La Motte soil test kit:

  1. Collect your soil samples. This soil test kit should have instructions on how to take a soil sample. However, not all soil test kits may have them. If yours doesn’t, you can follow the instructions on how to take a soil sample for lab testing. 
  2. Dry your soil. Make sure your lawn’s soil is dry when you take your soil sample. Then, leave the soil to dry on a sheet of newspaper.
  3. Read the instructions. Read the instructions carefully and wear protective gloves and eyewear as some chemicals can cause irritation.
  4. Fill: Fill a test tube to the fourth line with the pH indicator solution and add 1.5 grams of soil. 
  5. Shake: Put the cap on the tube and shake gently for one minute. 
  6. Settle: Let the solution settle for 12 minutes.
  7. Results: Compare the color of the solution to the pH color card to determine your soil’s pH. Although this test doesn’t use a pH tester, there are several that do.
  8. Other data: If you want to learn more about your soil, follow the instructions to find out more data, such as the levels of nitrogen, phosphorus, and potassium. Not all soil test kits test for other factors, though.

FAQ on Testing Your Soil pH 

What Affects Soil pH?

Four things affect soil pH: rain, decomposition, fertilizer, and your location.

  • Rain carries nitric, sulfuric, and carbonic acid from the atmosphere, making your soil more acidic. The effect gets stronger in urban areas, which have more nitric and sulfuric acid in the atmosphere.
  • Decomposition in the soil releases carbon dioxide, which forms carbonic acid when it reacts with moisture. This also makes your soil more acidic.
  • Nitrogen lawn fertilizers containing ammonium sulfate also lower the soil’s pH. Ammonium sulfate creates acidity when it naturally converts to nitrate in the soil.
  • Your location also can play a role in your soil’s pH. The Midwest tends to have more neutral, while soils in the Southwest and West tend toward alkalinity.

If you want to change your soil’s pH, you can do so by applying soil amendments. For example, lime makes your soil less acidic while sulfur makes it less alkaline.

What Else Can a Soil Test Tell You?

Aside from revealing pH levels, a soil test can also tell you about the following soil qualities:

  • Nutrient levels. Typical soil tests can tell you the nitrogen, phosphorus, and potassium (N-P-K) levels of your soil, which are the three macronutrients important for plant growth. Specialized tests also can tell you about other macro- and micronutrients such as magnesium, zinc, manganese, and calcium.
  • Cation exchange capacity. This measurement quantifies your soil’s capacity to hold nutrients. A higher number means your soil can hold onto more nutrients.
  • Base saturation. This measurement tells you how much of the nutrients your soil holds is actually useful to plant growth. A higher number means your soil is more fertile.
  • Organic matter. Coming from living things, organic matter improves soil health. It helps water penetrate the soil better, improves your soil’s ability to hold water and nutrients, and makes soil easier to work with.
  • Salt levels. Soil can retain excess salt, which isn’t good for plant growth. It leads to dehydration, drought stress, and higher soil pH levels.

Can You Test Soil pH With Vinegar?

Yes, you can; you can use baking soda, too. Mix some fresh soil with water and then vinegar in a 1:1 ratio to check for alkalinity; if it fizzes, that means your soil is alkaline. If it doesn’t bubble up, then you need to mix a fresh soil sample with water and then add baking soda to it, also in a 1:1 ratio; if you get a reaction, it means your soil is acidic. If nothing happens with either test, your soil is likely neutral.

Keep in mind that testing your soil this way only gives you a vague idea of its pH range. It’s not very helpful if you need specific numbers.

Call a Lawn Care Pro for a Healthy Lawn

Is soil pH important? Ab-soil-utely! However, it’s only one of many factors affecting your lawn’s overall state. A green lawn is much easier to achieve when you stay on top of your lawn care routine: mowing, irrigation, and fertilization. Sometimes, you might need to aerate or dethatch your lawn if it really needs it.

Not all homeowners are able to care for their lawns themselves. If you’re one of them but don’t want your lawn to become a weedy and patchy mess, then it’s time to call in a professional. LawnStarter’s network of lawn care pros can pamper your turf so you can take care of yourself during your free time. Hire a lawn care pro through LawnStarter today to get one step closer to a well-manicured lawn.

Main Image Credit: sherez / Adobe Stock

Janine Caayao

Janine Caayao

Janine Caayao has always been fascinated with growing plants, from fruits and veggies to bonsai trees and orchids. Now, she’s interested in urban gardening with her family. She loves finding new tips and tricks to keep their plants thriving.