The recent warm weather has many of us thinking about springtime. It will soon be time to start mowing our lawns (if we haven’t already, for the winter weeds that are flourishing) and, in April, to make the first fertilizer application of the season. I thought it was a good time to review basic care practices for our two most common turf grasses.
This week’s article is about centipede grass, and the next one will cover St. Augustinegrass. Best practices for these two turf grasses are different, and following recommended practices for one on the other will not result in the best health for that lawn.
Centipede grass is one of the most popular turf grasses in this area. It requires a smaller amount of fertilizer and less frequent mowing than some other common turf grasses.
If you use a slow-release fertilizer, you can get by with fertilizing centipede grass just once during the year. Slow-release fertilizer can be applied in April at a rate of 1 pound of actual nitrogen per 1000 square feet. For example, if you’re using a fertilizer that has the analysis 16-0-8 (16% nitrogen, 0% phosphate, and 8% potash), you would use 6.3 pounds of this fertilizer per 1000 square feet to get 1 pound of actual nitrogen.
If you are using a readily-soluble fertilizer rather than a slow-release one on centipede grass, you can split it into two applications – one in April and one in June – of 0.5 pound per 1000 square feet of actual nitrogen. If you were using the fertilizer 33-0-0 (33% nitrogen), you would apply 1.5 pound in April and 1.5 pound in June. If you want to encourage more growth, another application can be made in August.
For nutrients other than nitrogen, a soil test is necessary to know how much (if any) are needed. It’s important to use too much phosphorus on centipede grass. Repeated use of fertilizers like 8-8-8 and 13-13-13 can lead to a buildup of too much phosphorus and harm centipede grass lawns.
Centipede grass needs a soil pH between pH 5 and 6. This is more acidic than what’s preferred by many of our garden plants and most other turf grasses. However, many of our soils in the southeastern US naturally have a pH within this range.
A soil test is needed to know what the pH of a soil is. If pH is too high, you can apply sulfur to make it more acidic. In the uncommon case that soil pH is lower than pH 5, lime can be added to raise the pH. Sulfur or lime applications should be made based on soil test report recommendations. Even if a report recommends a great deal of sulfur, don’t apply more than about 8 pounds of sulfur per 1000 square feet at any one time to a lawn, to avoid injuring the grass.
Mow centipede grass at a height of 1 to 2 inches. It’s best to do it often enough that you don’t have to remove more than one-third of the total height of the grass when you mow. For example, if you’re mowing at a height of 1 inch, try not to let the grass get taller than 1.5 inches. If you’re mowing at a height of 2 inches, try not to let it get taller than 3 inches.
Sometimes, soil gets compacted and needs aerification. If you try to stick a knife into the soil when it’s neither very wet nor very dry and the blade doesn’t go into the ground easily, the lawn may need to be aerated. Late spring and early summer are generally good times to do this.
Let me know if you have questions.
Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).
