Oklahoma State University Turfgrass Science
September turf management tips
FALL FERTILIZER TIPS FOR A HEALTHY LAWN
Justin Quetone Moss
Proper fertilization can benefit turfgrass if applied according to certain recommended procedures. Bermudagrass is a warm-season grass with the majority of root growth occurring during the summer months. Cool-season grasses such as tall fescue may lose roots during the hot summer months, but the fall and spring are crucial for root growth. A lawn with a healthy root system will be better equipped to survive moisture and temperature extremes than those with poor root systems.
It is not necessary for homeowners to fertilize bermudagrass or zoysiagrass after early September in Oklahoma. Late, heavy applications of fertilizers containing Nitrogen can actually be detrimental to bermudagrass and zoysiagrass health by encouraging lush shoot growth which can sometimes lead to severe disease and/or winter injury.
Cool-season lawns such as tall fescue can benefit from a mid-late September fertilization with Nitrogen at a rate of 1 lb of actual Nitrogen per 1,000 square feet. The following are a few tips to remember when fertilizing your lawn.
- Always be sure to conduct a lawn soil test before applying fertilizers to your yard. You can refer to the soil testing collection procedures and fertilizer schedule as outlined in OSU Extension Fact Sheet HLA-6420.
- Always use properly calibrated fertilizer spreading equipment. For a good calibration starting point, you may wish to purchase a name brand or local retail brand fertilizer and an accompanying fertilizer spreader. The fertilizer bag will often tell you the proper setting on your fertilizer spreader for proper application of fertilizer to your lawn.
- Use fertilizers with a mixture of quick-release and slow-release nitrogen sources. Examples of quick-release (also called water-soluble) nitrogen include urea, ammonium nitrate, ammonium sulfate, diammonium phosphate, and potassium nitrate. Examples of slow-release (also called water-insoluble) nitrogen sources include methylene ureas, IBDU, urea formaldehyde, sulfur-coated urea (SCU), and polymer coated urea (PCU).
- Do not apply fertilizer to impervious surfaces such as sidewalks and driveways. If fertilizer gets on these surfaces, use a broom or blower to remove the fertilizer from the surface. Fertilizers left on the driveway or sidewalk are an environmental concern because they can easily runoff into drains or ditches.
- Lightly water-in fertilizers immediately following application. Do not apply fertilizer to your lawn immediately before heavy rainfall or deep irrigation.
If you have further questions about fertilizing your lawn during the fall, contact your local OSU County Extension Educator.