How to Conduct a Soil pH Test

digging soil up in a garden

The Spruce/Claire Cohen

Project Overview
  • Working Time: 30 - 45 mins
  • Total Time: 30 - 45 mins
  • Skill Level: Beginner
  • Estimated Cost: $20

As a home gardener, it's important to test your soil pH. Certain plants can only access the soil's nutrients if the pH is within a certain range. Not even the addition of generous plant food or fertilizer will help if your soil lies outside of a plant's preferred range.

Technically speaking, a soil pH (potential hydrogen) test measures how many hydrogen ions are in the soil. A pH less than 7 is acidic, 7 is neutral, and anything higher than 7 is alkaline. Acidic or alkaline soil isn't necessarily bad; it all depends on what you're growing. Most plants can adapt to soil pH that ranges from 6 to 7.5, but some plants have distinct preferences. For instance, blueberries prefer acidic soil while asparagus tends to do best in alkaline.

When to Do a Soil pH Test

Testing your soil's pH should be a fall garden checklist item. That way, you can amend the soil before winter or first thing in the spring before you plant. Plus, this is a good time to note any weeds that have grown throughout the summer, which can also give you clues about your soil pH. For instance, dandelions, wild strawberries, and plantain proliferate in acidic soil while chickweed, Queen Anne's lace, and chicory favor alkaline soil.

Moreover, performing your soil pH test in the fall gives you plenty of time to plant a nitrogen-fixing cover crop (for mild winter climates) or to tweak next year's planting to suit your reading. In the case of alkaline soil, you can lower the pH by adding organic materials, such as peat moss. Acidic soil can be neutralized by adding lime. The quantity you add depends on how much you need to change your pH.

What You'll Need

Equipment / Tools

  • Hand shovel
  • Clean glassware
  • Liquid measuring cup

Materials

  • Distilled water
  • Coffee filter
  • pH testing kit
  • Vinegar
  • Baking soda

Instructions

Testing pH Using Kitchen Supplies

An acidic solution generally reacts when it's added to something basic. Thus, you can use vinegar (acidic) and baking soda (basic) to give you a quick pH read of your soil. This test will uncover the general soil composition and is recommended for those who have relatively healthy gardens that might benefit from a little more targeted care.

  1. Dig for a Soil Sample

    Using a hand shovel, dig 4 to 6 inches below the surface of your garden to obtain a soil sample.

    digging up soil
  2. Clean the Soil

    Remove stones, sticks, and other debris from the soil. Be sure to break up any large clumps.

    removing sticks from soil
  3. Add Soil and Water Together

    Place approximately 1 cup of soil into a clean glass container, and add enough water to turn the soil to mud.

    adding water to soil
  4. Add the Vinegar

    Add 1/2 cup of vinegar and stir the mixture. If the soil fizzes, foams, or bubbles, your soil is alkaline.

    adding vinegar to the soil
  5. If No Bubbling Occurs, Repeat the Process

    Take a soil sample, clean it of debris, place it into a clean container, and turn it into mud.

    adding water to soil
  6. Add the Baking Soda

    Add 1/2 cup of baking soda and stir. If the soil fizzes, foams, or bubbles, your soil is acidic.

    adding baking soda to soil

Testing pH Using Soil Strips

Testing with vinegar and baking soda can tell you on which end of the pH scale your soil is leaning. But for an exact measurement, a soil pH testing kit is the way to go. You can purchase testing kits at most garden centers and through local cooperative extension offices.

  1. Dig for a Sample

    Using a hand shovel, dig 4 to 6 inches below the surface of your garden to obtain a soil sample.

  2. Collect the Soil

    Place 1 to 3 teaspoons of soil in a clean glass. Remove sticks, stones, and other debris.

  3. Pour in Distilled Water

    Fill the glass with distilled water to the same level as the soil sample.

  4. Agitate the Soil

    Vigorously stir or swirl the mixture. Let the solution rest for 30 minutes.

  5. Drain the Sample

    Pour the soil sample through a coffee filter and into another clean glass. Make sure that you are capturing the solids and allowing the liquid to pass through.

  6. Use the pH Test Strip

    Dip the test strip into the liquid. Pay close attention to the instructions on how long to leave the strip in the liquid. Compare the color it turns to the chart on the manufacturer's packaging to determine the pH.

  7. Repeat the Process

    Repeat the process several times with samples from different parts of your garden to determine an average pH.

Soil pH Testing Tips

If you test your soil using vinegar and baking soda and neither test produces much of an effect, your soil is probably in the neutral range. No further testing is needed.

You can mix soil from several different samples of a small garden for the vinegar-baking soda test. However, if you have a large garden, it is better to test several samples separately.

For garden soil that won't grow anything, it's best to send a soil sample to a lab for testing for a nominal fee. Based on the results, the experts can make recommendations to get you back on track.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Soil Testing. University of Maryland Extension Website