Guest Column - March 2010
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Field Maintenance

Spruce Up Your Sports Field for Spring

By Thomas Serensits


Bermudagrass

The following are recommendations for managing bermudagrass fields in the spring.

Bermudagrass begins to green-up when temperatures hit the 50s, but it does not begin active growth until temperatures reach the upper 60s. Once it does begin to grow, the same guidelines for springtime mowing of cool season grasses section should be followed. Here are some additional tips for bermudagrass fields:

  • Reduce mowing height several weeks before expected bermudagrass green-up to allow more light to warm the soil. Lowering the mowing height also stresses the overseeded ryegrass in preparation for removal.
  • Mowing regularly will also help knock down actively growing weeds that can flourish early in the spring in slow growing bermudagrass.

It is important to not push bermudagrass too soon with fertilizer because if the weather turns cold, there is an increased risk of cold temperature injury.

  • After there is no longer a threat of frost and the bermudagrass is actively growing, begin fertilizing based on your soil test results. Bermudagrass typically needs about 1 pound of nitrogen per 1,000 square feet per month during its growing season.
  • Quick-release nitrogen (urea and ammonium sulfate) usually works best for bermudagrass.

Cultivation practices should be done after the bermudagrass has fully greened-up and is actively growing (late spring and summer). If you perform these practices any sooner, you are increasing your risk for cold damage and weed invasion.

If you overseeded in the fall, the ryegrass must be removed to allow the bermudagrass competition-free growth in the summer. Many perennial ryegrasses have high heat and drought tolerance and will often persist well into the summer and limit bermudagrass growth. Remember, bermudagrass needs at least 100 days of competition-free growth in the summer.

  • If you don't need the green color from the overseeded grass in the spring, spray the field with Roundup (glyphosate) before temperatures warm up, making sure the bermudagrass is completely dormant. This is the best case scenario for the bermudagrass because it can green-up without any competition.
  • Cultural methods such as verticutting and aerifying are often ineffective at completely removing the overseeded grass.
  • Prepare to use transitional herbicides like Revolver (foramsulfuron), Tranxit (rimsulfuron), and Monument (trifloxysulfuron). These are effective at removing overseeded ryegrass without injuring the bermudagrass.
  • Temperature affects the amount of time it takes for the transitional herbicides to remove the ryegrass. It will take longer to kill the ryegrass if it is cold.
  • Timing is key—if you spray too early, your bermudagrass will still be brown when the ryegrass dies out and if you wait too long, you will be holding back the bermudagrass. The best time to treat is dependent on your location. If you time it perfectly, your ryegrass will be dying out just as your bermudagrass is beginning active growth.

Winter weeds can be a serious problem in dormant bermudagrass. For example, annual bluegrass thrives in the cool, damp conditions of late fall and early spring. Weed control at the beginning of spring is an important step to providing a great field.

  • If the bermudagrass is completely dormant, apply Roundup (glyphosate) to kill all actively growing weeds.
  • Applying a pre-emergent herbicide in the late fall or early spring will prevent weeds like annual bluegrass, crabgrass and goosegrass from germinating. Use a product with the active ingredient oxadiazon (Ronstar). Other products inhibit stolons from anchoring into the soil.
  • For broadleaf weed control, use herbicides that contain more than one active ingredient (e.g., Trimec) for broad spectrum weed control.
  • MSMA can be used for selective control of dallisgrass and other grassy weeds.
  • If you overseeded, use Velocity (bispyribac-sodium) to selectively remove annual bluegrass from overseeded ryegrass.

Spring can be both an exciting and stressful time for field managers. Make it easier on yourself by developing your maintenance plan before the weather breaks so you are ready to go as soon as the turf greens-up. Spring maintenance practices such as mowing, fertilization, cultivation practices and weed control lay the foundation for season-long success.



ABOUT THE AUTHOR

Thomas Serensits, manager of the Center for Sports Surface Research at Penn State University, prepared this article for the Sports Turf Managers Association (STMA). For more information, visit www.stma.org.