Spring Lawn Fertility

Lawns provide great benefits in urban settings by controlling erosion, filtering runoff before it reaches our streams and groundwater, and by moderating temperatures during the hot summers. Every homeowner has their own expectations of how nice their lawn should be. Some homeowners spend considerable resources to ensure a weed free, thick, healthy lawn with multiple applications of weed control products and many opt for irrigation and consequently, annual water costs.

fescueMany of us however, choose to maintain our lawns with minimal inputs. Less fertilizer, less pesticide use, and reduced water needs. When choosing a low maintenance lawn management plan, we must also accept the fact that our lawn will most likely not be that same dark green, uniform stand of grass as seen with higher maintenance lawns.

Proper fertilizer applications are important to provide the needed nutrients for the grass to remain healthy. To maintain good quality turf with minimum weeds, some nitrogen is required every year. Tall fescue needs 1.0-1.5 lbs of nitrogen per thousand square feet yearly. The best time to apply the nitrogen is from midOctober through late December. This timing allows the turf to develop a better root system to withstand the upcoming hot summer. Applying nitrogen in late fall also helps the turf recover faster and promotes an
earlier green-up in the spring.

Low maintenance lawns without regular irrigation should not require any nitrogen in the spring. So, what about the other nutrients like phosphorus or potassium? It is always best to get a soil sample to identify the need for other nutrients. Excess nutrients have many other consequences that extend beyond our own lawns. Brad Lee with the University of Kentucky explains this very well:

Excess phosphorus (P) can lead to algal blooms and subsequent degradation of Kentucky’s surface waters. In addition, these algal blooms have the potential to negatively impact much of Kentucky’s drinking water supplies. A recent analysis of 25 years of soil test P data from every county in Kentucky demonstrated that the average P levels in home lawns and gardens are considerably higher than agricultural soils. In addition, while agricultural soil P levels have been declining since 1990, the P levels in home lawns and gardens have been increasing at an alarming rate. These results indicate that homeowners continue applying unneeded P to their soils. It is imperative that homeowners test their soils prior to applying fertilizer. The soil test results will explain how much (if any) P is needed. Testing the soil for its fertility and applying fertilizer based on those soil test results will be less expensive for the homeowner and much better for Kentucky’s lakes, rivers and streams.

The best practice you can do for your low maintenance lawn includes a soil sample to determine what nutrients are needed and plan to apply nitrogen in the fall. Other good low maintenance practices include: keeping a sharp blade, mowing at the proper height, and applying pre-emergent if crabgrass has typically been a problem.

As always, your local University of Kentucky Extension Office can help you determine the best plan for your lawn.

Submitted by Andrew Rideout, Agent for Horticulture, Henderson Co. Cooperative Extension