Assessing Soil pH Without Harming Vegetation
Testing soil pH is an essential step in maintaining a healthy garden or lawn, as it helps understand the chemical makeup of the soil and its impact on plant growth. Here are some simple, low-cost methods to determine the pH level of your soil without using a commercial test kit.
Vinegar and Baking Soda Test
This quick and easy test involves placing some soil on a plate. Add vinegar; if it fizzes, your soil is alkaline (pH above 7). If no reaction, then add water to the soil and baking soda; fizzing indicates acidic soil (pH below 7). No fizzing means neutral soil.
Soil and Distilled Water Slurry
Mix soil with distilled water into a muddy slurry and let it sit for 15 minutes. You can observe the colour change or use simple pH indicator strips if available. Using distilled water is crucial to avoid contaminants that might distort results.
Using a pH Meter
A pH meter or probe can be purchased and used to measure the pH directly on moist soil or soil slurry by inserting the probe into the moistened sample. Although not a test strip, this method provides a precise pH value.
These methods provide a rough estimate rather than precise pH values but can be practical for quick field assessments or home gardening without specialized kits. For more precise and detailed soil pH and nutrient analysis, lab testing remains the best option.
It is recommended to test soil pH every 3 to 5 years, or when planting a new garden bed, moving to a new location, or growing a new plant variety with specific pH needs. If unsure about soil test results, contact a local Penn State Extension Office or a local agronomist or extension specialist for more information.
In addition to pH, other soil characteristics that may be included in the results are organic matter (OM) content, soluble salts (salinity), and cation exchange capacity (CEC). Soil test results also provide insights into the fertility of soil and what nutrients are present or may be needed for optimal plant growth, listing the amount of macronutrients nitrogen (N), phosphorus (P), and potassium (K); secondary macronutrients sulfur (S), calcium (Ca), and magnesium (Mg); and micronutrients copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), boron (B), chloride (Cl), nickel (Ni), and molybdenum (Mo) in the soil.
References:
[1] Penn State Extension - Soil Testing: Why, What, and How (https://extension.psu.edu/soil-testing-why-what-and-how)
[2] University of California Agriculture and Natural Resources - Soil pH (https://ucanr.edu/sites/Soils/Soil_Resource_Lab/Soil_pH/)
[3] Iowa State University Extension and Outreach - Soil pH Testing (https://www.extension.iastate.edu/soiltest/soil-ph-testing)
[4] University of Wisconsin-Madison Division of Extension - Soil Testing (https://learningstore.uwex.edu/Assets/PDFFiles/A3261_Soil_Testing_Flyer.pdf)
[5] University of Maine Cooperative Extension - Soil Testing (https://extension.umaine.edu/publications/4002e/)
