How to Test Your Soil's pH Using Cabbage Water

Sliced red cabbage on a wooden cutting board with a knife nearby — Credit:
Creative-Family / Getty Images

Boiled red cabbage water can be used as a simple DIY soil pH test by mixing it with soil and observing the color change after a few hours. The resulting color indicates acidity: pink/red for acidic, purple/blue for neutral, and green/yellow for alkaline soil.
For accurate results, the cabbage should be boiled in distilled water since tap water’s pH can skew the outcome. This ensures the color change reflects the soil’s pH rather than the water’s.
Knowing your soil’s pH helps determine which plants will thrive, as some require specific conditions like acidic soil (e.g., blueberries, azaleas). The leftover cabbage water can also double as a nutrient-rich plant fertilizer after testing.

If you're unsure about the pH of your backyard soil, expert gardener and author Simon Akeroyd shared a simple test on his Instagram (@simonakeroydgardenwriter)—and it uses an unexpected ingredient.

After you’ve boiled or steamed red cabbage, you can use the residual cooking water to test the pH of your soil. Simply strain the cabbage leaves and leave the water to cool. Pour the cooled blue cabbage water into a jar or glass and add a teaspoon or two of soil. Give it a swirl and let the mixture sit for a few hours, then observe any color change in the water to determine your soil's pH.

If your water turns pinkish-red, then you have acidic soil (low pH); blue or purple water indicates neutral soil (a pH of around 7); and green or yellow water indicates alkaline soil with a high pH.

For the most accurate results, he explains in the caption that it's best to boil the red cabbage in distilled water, as it has a neutral pH. Your tap water may have a high or low pH, which could affect the results.

Most plants prefer neutral soil, but others prefer acidic or alkaline soil. For example, rhododendrons (including azaleas), camellias, most magnolias, blueberries, cranberries, and many carnivorous plants will only grow in acidic soil, Akeroyd says. So, it's worth checking the pH of your soil before purchasing plants.

After you've tested the pH of your soil, you can use the cabbage water to water your plants. It's packed with nutrients and makes a great plant food, Akeroyd explains.

How to Test Your Soil's pH Using Cabbage Water—No Kit Required

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