Attention, Johnson Countians: If you want to do your part against polluted streams and ponds, there’s a free soil test with your name on it at the Kansas State Research and Extension Office.

The office hopes to do 200 soil tests before the end of the year as part of an effort to prevent excess fertilizer from making its way into the water, said Dennis Patton, horticultural agent. The idea is to show residents how much fertilizer they need, so they won’t overdo it.

The effort is a partnership between the extension office and the Johnson County Stormwater Management Program. The county budgets about $15,000 a year for 1,000 soil tests. So far, about 758 have been done, Patton said.

The funding comes from a one-tenth-cent countywide sales tax and is part of the public outreach required by the Kansas Department of Health and the Environment, said Heather Schmidt, county water quality specialist. The soil test program is now in its third year, she said.

No reservations or special equipment is needed, Patton said. To get the soil test, residents should just bring about two cups of their soil in a plastic bag into the extension office at 11811 S. Sunset Drive, Suite 1500, Olathe. The soil then goes off to Kansas State University for analysis. When the results return, the extension office interprets the numbers and gives advice about the type and amount of fertilizer to use. Normally, all that would cost $12, Patton said.

The best way to take a soil sample is to go around your property taking scoops of dirt from two to four inches below surface in six or seven places, Patton said. Then mix all that dirt in a big container and spoon out about two cups for the test. That method gives a true reading of the area’s needs.

“If you get the sample all from one place, that could be the spot you spilled fertilizer last year,” he said.

One of the most common mistakes people make is in overfertilizing or spreading it over sidewalks and driveways, he said. When that happens, extra nitrogen and phosphorus washes out and causes algae blooms in the streams.

Stormwater officials take a lot of calls about algae in the summer, Schmidt said. “One of the ways people can help keep their contributions to pollution to a minimum is to know what their lawn care needs are,” she said.

The soil tests take the guesswork out for gardeners, Patton said. “To really do it right involves math and very few adults want to do math,” he said.

The growing season is over, but fall and early winter are still good times for the tests, Patton said. In November and December, there’s plenty of time to look at the results and plan for next spring.