How to Test the pH Level of your Soil without a Kit

If you’re wondering why those blueberries you planted a while back are not growing to their full potential, it is probable that you forgot to check your soil’s pH level.

The pH level indicates whether your soil exhibits an acidic, alkaline or neutral tendency. The pH scale ranges from 1 to 14, with 1 through 6.5 being acidic and 7.5 through 14 being alkaline. Levels between 6.5 and 7.5 are considered neutral.

You can buy a soil pH test kit or send a sample of your soil to a professional for testing and get an actual reading on the numeric scale. If you are having issues with your soil or are planning to invest a lot of time and money into improving your garden soil, it is recommended that you have your soil professionally tested. Look up a local soil test lab in your area, or contact your local University Extension office. Professional soil tests for home gardeners are usually very affordable, and with the results, you will receive specific recommendations for improving your soil.

But if you are just curious about the general state of your soil or want a fun, educational activity, you can do simple tests at home to gauge the pH level of your soil without a kit.

While numerous plants grow perfectly well in neutral soil, some plants have an inclination for either acidic or alkaline soil. Therefore, checking the soil’s pH is an essential part of the preparation for any kind of planting or you’ll wish for melons and end up with grapes. Even your yield would be as bad as the joke in the previous line.

General Preparation for Checking Soil pH

Before you experiment, you need to collect a sample of soil from your garden or farm, wherever you wish to grow the plants. The sample of soil collected must be thoroughly plowed before digging in.

Things you’ll need:

• Plastic bowl
• Gardening gloves
• Hand Trowel

Start by collecting the soil sample you want to check.

Step 1. Dig the soil

Use a hand trowel to dig up a sample of your garden soil from at least four inches below the surface. Collect a small amount from 3 or 4 different spots in your garden and mix them together, ensuring your results will reflect the whole garden, rather than one small spot.

Step 2. Put the soil in a container

Fill the plastic bowl with soil.

Step 3. Remove stones from the soil

Remove any small pebbles or stones from the soil. Now you can use the soil in the container for your pH testing.

Method 1: Red Cabbage

This is an excellent method to validate the pH level of soil as it is pretty accurate. It uses a red cabbage solution that changes to different colors when mixed with acidic or alkaline substances. The intensity of color shift indicates how high or low is the pH level from neutral.

Things you’ll need:

• Baking soda
• Vinegar
• Red cabbage
• Distilled water
• Bowl containing soil

The method is divided into 3 parts:

• Preparing the solution
• Testing the Solution
• Testing the Soil

Part 1. Preparing the Solution

Step 1. Chop red cabbage

Chop at least half a red cabbage finely on a cutting board.

Step 2. Put chopped cabbage in a blender, add little water and blend

Put the chopped cabbage in the blender with a minimal amount of distilled water.

Add enough water to just help blend the cabbage. Do not drown it with water.

Step 3. Add more water if needed

If you encounter a problem in blending it, use a spoon to stir the contents thoroughly and add a little more water to continue blending with ease.

Step 4. Pour water in a boiling pot

Now, pour 2 cups of distilled water into a boiling pot. Heat the water until it starts to boil.

Step 5. Pour blended cabbage in the pot

Pour the contents of the blender into the pot and allow it to boil for 5 to 10 minutes. If you feel the cabbage blend is not properly immersed, add another ½ cup of water. It makes the total amount of water in the pan 2 ½ cups.

Remember, the amount of water in the pot depends on your discretion, but to be on the safe side, do not pour more than 3 cups for half a jar of blended cabbage.

Step 6. Turn off the heat and let it steep

Turn off the heat and put the lid on the pot. Let the water absorb the essence of the cabbage (anthocyanin) for 20 to 30 minutes.

Step 7. Strain the contents

After 30 minutes, filter the liquid into a jar using a fine muslin cloth. You can use a coffee filter if you don’t have a muslin cloth.

You will now have a concentrated bluish-purple solution.

Part 2. Test the Solution

Step 1. Pour red cabbage solution in test containers

Pour some quantity of the solution into two of the three glass containers.

Step 2. Add baking soda

Add half a spoon of baking soda to one of the containers.

Step 3. Color changes from purple to blue

You should observe a color shift from bluish-purple to turquoise blue after adding the baking soda, which is alkaline in nature.

Step 4. Add vinegar

Now, add half a spoon of vinegar by approximation to the other container.

You should observe a color shift from bluish-purple to pink after you add the vinegar, which is an acid.

If the color in each container changed as described above, you know your cabbage solution is capable of telling the difference between an acid and an alkaline substance.

Part 3. Test the Soil

Step 1. Add soil in a test container

Now, you can test your soil. Put 1 tablespoon of soil into the third glass container.

Step 2. Pour red cabbage solution in the test container

Now, pour some of the red cabbage (anthocyanin) solution into the container.

Step 3. Mix the contents and allow the soil to settle down

Gently mix the contents with a spoon or spatula. Let it sit for about 5 minutes to allow the soil to settle in the solution.

Step 3. Note the color change

If you observe a color shift toward pink or red, your soil is acidic. If the color shifts toward blue or green, your soil is alkaline in nature. If there is no color change, your soil is neutral.

In this example, the solution turned steel blue indicating the soil we used is alkaline.

Once you know the pH of your soil, you can choose to grow plants that thrive at that pH level, or you can try and amend your soil to achieve your desired pH level. You can add a little bit of sulfur to your soil to lower the pH, or add a bit of powdered limestone to raise the pH.

Method 2: Baking Soda and Vinegar

This is the easiest method to check the pH level of the soil. This experiment will not provide the actual value of the pH level, but it is precise enough to verify whether the nature of the soil is acidic, neutral or alkaline.

Things you’ll need:

• Vinegar
• Baking soda
• Distilled water
• Bowl containing soil

There are three tests in this method:

• Acidity Test
• Alkalinity Test
• Neutrality Test

Part 1. Acidity Test

Step 1. Put soil in a test container

Take a spoonful of soil from the bowl and put it in one of the containers.

Step 2. Pour distilled water

Pour distilled water in the container, using enough to immerse the soil.

Step 3. Add baking soda

Now, add half a spoon of baking soda. Stir the contents of the mixture slowly for a few seconds. If the mixture begins to fizz with a small popping sound, your soil is acidic in nature, and there is no need to perform the next test.

No fizz was obtained in the above case.

Part 2. Alkalinity Test

Step 1. Put soil in a test container

If you did not observe any fizz in the previous step, take another spoonful of soil from the bowl and put it in the other small glass container.

Step 2. Add vinegar

Add enough vinegar to just immerse the soil. If the mixture begins to fizz with a small popping sound your soil is alkaline in nature.

In this example, the fizz was observed indicating the soil we used is alkaline.

Part 3. Neutrality Test

If there wasn’t any fizz in either of the tests above, then your soil is neutral.