Soil pH Testing

Two squash plants, one in soil with the correct pH, the other not.

Soil is Important!

Why is soil important? Read “Soil – the Good Gardener’s Secret.”

Why is soil testing important? Benefits are detailed in our Soil Testing fact sheet.

Ready to get your soil tested? The soil testing resources below can help.

Getting Started: Free MMGA Soil pH Testing (temporarily on hold due to Covid-19)

Whether you have an existing lawn/garden, are rehabilitating an older property, or are considering new plantings, a soil pH test is a good starting point.

What is pH and Why Should I Care?

Potential of Hydrogen (pH) is a measure of soil acidity or alkalinity. It uses a 14-point scale: A pH of 7 is neutral. A pH less than 7 is acidic; greater than 7, alkaline.

Different plants have different pH and nutrient requirements: Blueberries, for example, like acidic soil with a pH of 4.5-5.5; vegetables such as lettuce, spinach, cabbage and peas like soil with a pH of 6.0-7.5.

The photo above shows two squash plants planted the same day by the same person: same variety, same seed pack, and same planting depth. The big green plant is in soil with an optimal 6.1 pH; the little yellow plant is in soil with a pH of 5.3 (too acidic).

While pH is not in itself an indication of soil fertility, it does affect the ability of plants to access nutrients. Your soil may already contain adequate nutrients, but plant performance may be limited by an unfavorable pH level. Once you know your soil’s pH you can make more informed decisions regarding plant selection or the possible need for soil amendments.

To see the soil pH preferred by selected plants, check out the Old Farmer's Almanac Optimum Soil pH Levels for Trees, Shrubs, Vegetables, and Flowers.

Digging Deeper: Comprehensive Soil Testing

While pH is important, it isn’t the only consideration. A number of New England institutions offer inexpensive detailed soil tests that also examine soil texture, nutrient and micronutrient levels, organic matter content and the presence of toxic heavy metals (including lead and cadmium). If the results for any factor are outside of the optimal range for the plants you are growing, a comprehensive soil test will provide guidelines for fertilizers and other steps you may wish to take. Recommendations are based on environmentally-friendly soil fertility management practices.

Comprehensive soil tests are performed for a fee by many universities and private laboratories. Check out the New England soil testing facilities below. Review which tests they offer as standard vs. optional (usually for a slight additional charge), and be sure to follow soil sampling instructions carefully. Test results are only as good as the sample you provide.

NOTE: Soil characteristics vary from region to region. Testing labs base their evaluations on regional norms. If you live outside of New England and are interested in having your soil tested, contact your local Cooperative Extension Office for information about resources in your area.

Help with Other Issues

Soil testing will NOT identify problems related to inadequate sunlight, soil drainage, weeds, insects, diseases, pesticides, herbicides and other sources of damage. For help understanding these or other issues, contact us at one of the Helplines.