(News article for March 20, 2020)
In previous articles about dealing with lawn weeds, I’ve mentioned that good cultural practices are the foundation of good weed management. Good cultural practices include maintaining soil pH in the optimum range, fertilizing at recommended times and rates, and mowing at an appropriate height for the turfgrass that you have.
Today, I’m going to elaborate on cultural practices for centipedegrass. Next week, I’ll address another common turfgrass, St. Augustinegrass. Best practices for these two turfgrasses are different, and using the recommended practices for one on the other will not result in the best health for that lawn.
Centipedegrass is one of the most popular turfgrasses in this area. It requires a smaller amount of fertilizer and less frequent mowing than some other common turfgrasses.
If you use a slow-release fertilizer, you can get by with just fertilizing centipedegrass 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 fertilizer on centipedegrass, you can split it into two applications of 0.5 pound of actual nitrogen – one in April and another in June. So, 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 0.5 pound of actual nitrogen can be applied in August.
For nutrients other than nitrogen, a soil test is needed to know how much (if any) are needed. It’s important not to overapply phosphorus/phosphate to centipedegrass. Repeated use of fertilizers like 8-8-8, 10-10-10, and 13-13-13 may lead to a build up of too much phosphorus and harm centipedegrass lawns.
Centipedegrass 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 turfgrasses. However, many of our soils in the southeastern US naturally have a pH within this range.
A soil test is needed to know for sure what the pH of a soil is. If pH is too high, sulfur can be added 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. Addition of sulfur or lime should be done based on soil test report recommendations. Even if a report recommends a great deal of sulfur, don’t apply more than about 8.5 pounds of sulfur per 1000 square feet at any one time to a lawn.
Mow centipedegrass at a height of 1 to 2 inches. Mow 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 the soil is neither very wet nor very dry and the blade doesn’t go into the ground easily, the soil may need to be aerated. Late spring and early summer are generally good times to do this.
I want to point out that the turfgrass section of our website has recently been updated has a lot of useful information on it.
Let me know if you have questions.
Contact Mary Helen Ferguson.