Extension notes is written by K-State Extension of Harvey County extension agents Scott Eckert, Susan Jackson and Ryan Flaming. They focus on horticulture and agriculture.
Not all lawns are created equal. Fertilizing a warm season lawn like buffalo or Bermudagrass is done in the summer months while correct fertilizing of fescue or Kentucky bluegrass is done mostly in the fall.
Warm-season grasses grown in Kansas include bermudagrass, zoysiagrass and buffalograss.
March - Spot treat broadleaf weeds if necessary. Treat on a day that is 50 degrees F or warmer. Rain or irrigation within 24 hours of application will reduce effectiveness.
April - Apply crabgrass preventer between April 1 and April 15, or apply preventer when the eastern redbud is in full bloom. If using a product with Barricade, apply two weeks
earlier. Crabgrass preventers need to be watered in before they will start to work.
May - August 15 - Fertilize with 1 lb. of nitrogen per 1,000 square feet per application. Remember, more applications will give a deeper green color, but will increase mowing and lead to a buildup of thatch with bermudagrass and zoysiagrass.
Bermudagrass - Use two to four applications.
Zoysiagrass - Use one to two applications. Too much nitrogen leads to thatch buildup.
Buffalograss - Use one to two applications. One Application: Apply in June. Two Applications: Apply May and July. Three Applications: Apply May, June and early August Four Applications: Apply May, June, July and early August.
Fertilizing lawns at improper times will encourage unwanted weeds.
If grubs have been a problem in the past, apply a product containing Merit or Mach 2. Either product should be applied by mid July. Merit can be applied as early as mid May if there are problems with billbugs or May beetle grubs. Both of these are referred to
as grub preventers. Actually, they kill the grubs when they are small but are called grub preventers because they kill the grubs before they cause damage. These insecticides are effective and safe. They must be watered in before they become active.
June is a good time to core aerate a warm-season lawn. Core aeration will help alleviate compaction, increase the rate of water infiltration, improve soil air exchange and help control thatch.
Late July through August - If you see grub damage, apply a grub killer. If Merit or Mach 2 has been applied, this should not be necessary. Grub killers must be watered in immediately.
Late October - Spray for broadleaf weeds if they are a problem. Treat on a day that is at least 50 degrees F. Rain or irrigation within 24 hours reduces effectiveness. Use the rates listed on the label for all products mentioned.
Timing is everything when it comes to turf. As you can see not all lawn grasses are created equal.
— Scott Eckert is a Kansas State Research and Extension Agent for Harvey County. Horticulture is his specialty.