Soil pH - Acid Soil or Alkaline Soil - What You Need to Know

Your Soil pH can have a profound effect on your garden. Those of you who rely on chemical fertilizers will need to pay close attention to your pH as it will affect what nutrients are available to your plants. As you use compost and start to work more closely with the soil microorganisms, those critters will start to work their magic buffering pH levels to suit the plants you are growing.

What is Soil pH?

Soil pH testing is done to see how acidic or alkaline your soil is. pH means potential Hydrogen. It measures the number of H+ ions in the soil water.

It's a logarithmic scale that goes from 0 to 14 with 0 being most acidic, 7 being neutral and 14 being most alkaline. Because it's a logarithmic scale each jump is a ten fold increase so a soil with a pH of 5 is 10 times more acidic than one with a pH of 6 and a 100 times more acidic than one with a pH of 7.

Testing your Soil pH

You can of course send a sample of your soil to a lab for a pH test but then you couldn't pretend to be a scientist or a CSI.

Here is a quick and simple way to test if your soil is acidic or alkaline.

  • Take a small handful of soil and rub your hands with it. This will clean off anything on your hands that might affect the soil.
  • Take another clean handful of soil. Wet the soil with vinegar. If it fizzes and bubbles you have alkaline soil.
  • Take another clean handful of soil. Add baking powder and then wet the soil baking powder mix with distilled water. If it fizzes your soil is acidic.

Now you have a bit of info and you probably want to know how acidic or alkaline your soil is.

When I first looked at soil pH test options I figured you had to buy a soil pH test kit to test soil. However I have since discovered that a whole range of pH test strips including those for urine and saliva, for aquariums, and for water should be just dandy for testing soil. Here are a couple of examples of test strips and rolls of pH paper that would be suitable.and are available from

Hydrion Ph paper (93) with Dispenser and Color Chart - Full range Insta Chek ph- 0-13
Learning Resources Ph Paper

When you look for pH test strips you need to notice the pH range they test. Many strip or rolls of test paper say they are universal and test from pH 1 to 14. This would be fine. Some however test a smaller range. Ideally you want test paper that includes pH from 4.5 to 10 for soil testing.

To use the test strips:

  • Wash your hands with some or the soil.
  • Take a small handful of soil and wet it thoroughly with distilled water.
  • Touch the test strip to the water and soil and wait for the color to change.
  • Compare the color to the color chart that comes with strips. Take the reading from the area that is closer to the soil rather than further away where the water wicks up to.

To test the pH you can also use a pH meter or indicator agents.

Luster Leaf 1840 Rapitest Soil pH Meter
Luster Leaf 1663 Professional Soil Test Kit with 80 Tests

To use a pH meter you simply plunge the rod into the damp soil and a needle will jump to the approximate pH reading for your soil. It takes about a minute. Make sure the soil is damp or you will not get a reading.

The second way is with indicator agents. Your kit will come with detailed instructions. The one pictured above can do 20 pH tests but is also good for testing NPK - Nitrogen, Phosphorus and Potassium.

The most important thing is to use distilled water for everything as your tap water will likely skew your results. The process of doing these kinds of tests for your soil is very fun and one you can share with your kids. Even those not too crazy about science will like the process.

Here is a video with a detailed closeup of someone doing a pH test using pH test strips. It starts off with the gentleman shaking a soil water slurry. This slurry is made with equal volumes of soil and water. When measuring your soil don't include rocks or vegetation.

What's Next...

Now that you know your approximate soil pH check out our next page to find out what it all means.

Or go back to Soil Testing or Home to The Compost Gardener.