As home gardeners begin to think about their spring plantings and renewing their lawns, they should also put some thought into the quality of their soil. The University of Rhode Island is making that easier for gardeners by offering free testing of soil pH throughout the growing seasons.
“You need to understand your soil if you’re going to have much success at growing a healthy garden or lawn,” said Rosanne Sherry, who directs the URI Master Gardener Program. “And the first step to understanding your soil and solving any problems it may have is learning its pH.”
pH is a measure of soil acidity or alkalinity. The pH of native, uncultivated soils in southern New England is typically 4.5 to 5.5, which is ideal for growing native plants like blueberries, rhododendrons and azaleas. But most cultivated garden plants, vegetables, and lawn grasses grow best when the pH is between 6 and 7, according to Sherry. When pH is too low, the soil ties up all the nutrients and plants struggle to grow.
The addition of lime to the soil – about 50 pounds per 1,000 square feet - will make the nutrients more available to plants and enable the growing of a lush garden. Sherry noted that it takes about two or three months for pH to change after the addition of lime, so it is best to apply lime in the fall. Spring lime applications don’t kick in until the beginning of summer.
URI Master Gardeners will conduct the pH tests for Rhode Islanders who bring a sample of their soil to the URI Outreach Center on URI’s Kingston campus between 10 a.m. and 1 p.m. Monday through Thursday. The test takes about 15 minutes, and gardeners are asked to wait for the results rather than dropping off the sample and returning later. Mail-in samples will not be accepted.
A total of about one cup of soil should be collected from several locations in the garden at a depth of about six inches and placed in a plastic Ziploc bag. Along with the results of the test, the Master Gardeners will also provide a recommendation for the quantity of lime that should be administered, if any.
“And while you’re there, we hope you’ll stay and ask questions of our Master Gardeners,” Sherry said. “They are a wealth of knowledge and will enjoy sharing their expertise.”
For more information about soil testing, call the URI Gardening Hotline at 1-800-448-1011 or 401-874-4836. The URI Outreach Center is located at 3 East Alumni Ave., Kingston.