Don’t “P” on your lawn
Algae bloom in a local pond
Photo contributed
By Terasa Lott
Water Resources Agent
Clemson Cooperative Extension
With fall approaching, it’s important to share some fertilizer tips both for the health of your lawn and the health of our local waterways. Just remember, “Don’t P on your lawn.”
The “P” in this case is phosphorus, a nutrient found in most lawn and garden fertilizers. When fertilizers run off lawns into waterways, the phosphorus can feed algae leading to ugly, stinky, and potentially toxic algae blooms. This is a topic that was n the news a lot this summer as a result of the algae bloom along Florida’s coast.
Even if you don’t live near a body of water, your lawn care practices can still impact water quality. Storm drains, the grates you see in parking lots and on the edges of roads, lead directly to waterways and receive no treatment whatsoever.
Before purchasing or applying fertilizer, you should have a soil test. Clemson Extension offers a basic soil test for $6. Soil samples may be dropped off at your local Extension Office or at Gardner’s Fertilizer and Farm in Hartsville. In my humble opinion, that fee is worth every penny. The soil test will provide a recommendation of the fertilizer formulation as well as the amount to apply. The formulation is three numbers that represent nitrogen (N), phosphorus (P), and potassium (K).
If the soil test recommendations show a zero as the middle number, that indicates no phosphorus is needed. This is fairly common, as our soils tend to be naturally high in phosphorus. In this instance, you would purchase a P-free or phosphorus free fertilizer. It can be a little more difficult to find P-free formulations so you may need to look beyond a big box store. Phosphorus should only be used if recommended by a soil test.
In addition to frugal use of phosphorus, timing is critical with fertilizer application. Nitrogen applied too late in the growing season can lead to winter injury. For centipede lawns, nitrogen-containing fertilizer should not be applied after August 15. It might seem like a good idea to give your lawn a boost but in reality, you are likely to cause problems down the road.
Taking care of your lawn can be quite challenging but Clemson Extension has maintenance calendars for each of the common turfgrass species that outlines what to do and when to do it. You can find these maintenance calendars on Clemson’s Home and Garden Information Center (HGIC) at www.clemson.edu/hgic. Simply search “maintenance calendar” once you reach HGIC.
Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, gender, religion, national origin, disability, political beliefs, sexual orientation, gender identity, marital or family status and is an equal opportunity employer.