How do I measure the pH levels of my houseplant's soil?

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If you've taken care of plants for a while, you might have heard something about acidic soil before. If you're like me, you kind of knew what that meant, not what to do with that information. Why is it important? Does it have any impact on your plant? Let's figure that out in this plant care guide!

What does acidic and alkaline soil mean?

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Before we look at how we can measure the pH levels of the soil, we'll need to get an idea about what acidic, alkaline, and pH levels means.

So first, what are pH levels? PH levels are a way to measure how acidic or alkaline something is, like the soil for your plants. The pH scale goes from 0 to 14. If something has a pH level less than 7, it is considered acidic, and if it has a pH level greater than 7, it is considered alkaline.

A pH level of 7 is neutral, which means it is neither acidic nor alkaline. Understanding the pH level of your soil can help you know if your plants are getting the right nutrients they need to grow healthy and strong.

An example of something that is acidic is lemon juice, which typically has a pH level around 2. An example of an alkaline substance is baking soda, which has a pH level around 9. Pure water, on the other hand, is an example of something with a neutral pH, as it has a pH level of exactly 7.

So with this in mind, let's take a look at how we can find the pH level of our plant's soil.

Measuring the pH levels of plant soil

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Photo by Backyard Boss (CC BY 2.0)

The pH level of your plant's soil has a huge impact on your plant's health. Get it right and your plant thrives, but get it wrong, and it'll struggle to survive.

Option 1: Soil pH test kit / Litmus paper

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You can purchase a soil pH test kit from a garden center or online to test whether your plant's soil pH levels. It's important to follow the instructions provided with the kit. Usually, you'll need to mix a small amount of soil with a solution and compare the color change to a chart. This will roughly tell you the pH levels of your soil.

Option 2: Digital pH meter

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If you're not looking for a manual process, but would rather just do a quick test, you can get a digital pH meter. It's typically a little more accurate and much easier to use. With most meters, you stick the probe into the soil and read the pH level on the meter display. After you're done testing your self, make sure to clean the probe to keep the readings accurate.

Option 3: Homemade vinegar and baking soda test

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If none of those options are good for you, you can do a little home test. Keep in mind, this isn't a very accurate test, but can give you an idea if the soil is alkaline or acidic.

To perform this test, take two samples of soil from different parts of the pot, mix them both with distilled water. Add vinegar to the first sample. If it fizzes, the soil is alkaline. For the second sample, add baking soda mixed with water. If it fizzes, the soil is acidic. If nothing happens, your soil is pH neutral.

This method is not very accurate, but it can give you a clue about steps to take to improve the soil for your plants.

What you can do with the pH level results

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So you've done a test, got a result, but now what? Well, that depends on the plant you're growing in the soil. If you've found out your soil is alkaline, but you're trying to grow a Venus flytrap, you'll need to make the soil more acidic. The same goes for growing lavender in acidic soil: you'll need to make the soil more alkaline.

Adjusting soil pH

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You can adjust the pH levels in your plant's soil by adding supplements to the soil:

• To raise pH (make more alkaline): Add lime (calcium carbonate) to the soil.
• To lower pH (make more acidic): Add sulfur or organic matter like peat moss.

When you adjust the pH levels in the soil, make sure to test your soil after making adjustments. Especially in the beginning, you'll have difficulty to determine how much to add, so you'll need to test regularly to make sure the soil is still the right growing environment for your plant.

Also, remember to take it slow, do little bits at a time and give your plant time to adjust. Any environmental change can stress your plant and they'll likely need some time to adjust, so give it that time.

Thank you for reading this post! I hope it helps you to keep your plants healthy and beautiful! If you're looking for more guides on specific plants, you can always request a plant guide to get a guide for the plant you have trouble with.