City warns residents not to over-fertilize lawns

(April 21, 2008) - With summer upon us, many City residents want lush, green lawns and are turning to fertilizer to do the trick.  But before putting chemicals down on a yard, be sure that it’s applied the right way.  Over-fertilization of lawns can cause a run-off of chemicals that flow down storm drains and into the City’s creeks and rivers, polluting City waterways.

“Fertilizer feeds plants the nutrients needed for vigorous growth,” Environmental Unit Supervisor Derek Johnson said.  “When these nutrients run off in storm water flows, the same process occurs in a river or pond, which can lead to an algae bloom.

This algae overgrowth doesn’t only impact the aesthetics of a waterway, it can also impair fishing, cause taste and odor problems in drinking water and decrease the life span of ponds and lakes.  Also, when the plant tissue dies, decomposition reduces the oxygen in the water, which can lead to loss of aquatic animal life.

The City’s Storm Water Quality division responds to multiple calls each year about excessive algae or other nuisance aquatic vegetation.

“Local studies indicate that many City residents are over-applying fertilizer, mainly the nutrient phosphorus,” Johnson said.

In order to avoid over-fertilization, Allan Storjohann of the Myriad Botanical Gardens recommends lawn fertilizers with 20 percent or less nitrogen content.  He also encourages buying organic products with slow-releasing fertilizer pellets.

City residents can have the soil in their yards tested to tailor the fertilizer to what their lawns actually need.  Call the Oklahoma County OSU Extension Office at 713-1125 for more information about soil testing and proper use of fertilizer.