Teaching Kids about Soil pH

Fall is good time to do a soil test to check the nutrient levels in your soil and your soil pH. Testing the pH is also a good activity to do with kids. You can take soil samples and either ship them off to a soil lab for testing or use a home soil-testing kit to measure the pH levels. Focusing on pH is a great way to teach science and math to your kids while showing them how to improve the soil. Here are some suggestions for teaching kids about soil pH:

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Explain to your kids what pH is. It’s the measure of the soil’s alkalinity and acidity and is measured on a scale of 1 to 14. The higher the number, the more alkaline the soil. Seven is neutral.

Ask your kids why pH is important. Explain that the soil pH will help dictate what nutrients can be taken up by certain plants. All plants have a preferred pH range where they grow best. For example, blueberries like an acidic pH. If the soil pH is too high, the blueberry plant won’t be able to take up iron and it will not grow well. Ask kids to research the ideal pH for a variety of plants growing in their school yard or their yard at home.

Explain that there are certain materials that can raise or lower the pH in soils. The most common are sulfur, which lowers the pH and make soil more acidic, and lime, which raises the pH and makes soil more alkaline. Ask your kids to research other materials that might raise or lower the pH (one example is wood ash, which raises the pH).

Take you kids into the landscape and teach them how to apply these materials to the plants, following the directions on the label and taking into consideration the known pH level of the soil around that plant. Have them calculate how much lime or sulfur they need to add to raise or lower the pH to the desired level. Explain that because they are adding these materials in fall, the materials will have time this winter to break down and influence the soil pH by spring.