Homeowners often contact the Extension office with questions about their lawn. Here are some examples:
- “My lawn has bare patches. What’s wrong with it?”
- “When do I fertilize my lawn and how often?”
- “How can I tell if the problem is disease or pests?”
The University of Florida/IFAS Extension has free online publications and local county Extension offices that can help you solve lawn problems.
Check this site to find your local county Extension office: SFYL.ifas.ufl.edu/find-your-local-office/.
If you’d like to do your own research, a good rule of thumb is to type the topic you want to learn more about in your computer’s web browser and the letters “UF” after it.
For example, to learn more about St. Augustinegrass, type St. Augustinegrass + UF to get a list of free publications and online resources. Try it!
When it comes to addressing lawn problems, you first need to know what type of grass that you have. Is it St. Augustinegrass, bahiagrass, zoysiagrass or Bermudagrass?
Next, you need to identify when symptoms first appeared?
Next, you need to consider: Were there any recent construction projects? New soil brought in? Pressure-washing or cleaning?
Those activities can cause sudden changes in turf/symptoms.
And, whether you maintain your lawn yourself, or you employ a lawn maintenance company, you need to know when pesticides, herbicides and/or fertilizers are applied, and the types of products used. These practices affect the lawn.
Turf maintenance plans make up part of the story, and it’s easier to solve problems and be an informed consumer if you have information about what products are applied and when they are applied.
St. Augustinegrass is the most common lawn here.
There are different cultivars of St. Augustinegrass, such as ‘Floratam,’ ‘Palmetto,’ and ‘Seville.’
It can be helpful to know the cultivar because some are better adapted for shade or have lower mowing heights.
If replacing parts of your lawn with new pieces of turf, try to match the cultivar to what you already have in your lawn.
Bare patches in St. Augustinegrass may be caused by insects, irrigation problems, large patch (cool weather), or take-all root rot (warm weather).
Beginning in April, start watching for signs of lawn pests. If you see bare patches in the lawn, it’s important to figure out the cause because if it’s a fungus, and the grass is treated for insects, the problem won’t be corrected since the control doesn’t match the cause.
Let’s say you suspect mole crickets or chinch bugs.
If you’re up for an experiment, there is an easy way to find them. (If you don’t find them, it may be a fungus.)
To look for insects, you can do an inexpensive and quick soap flush. If you do the soap flush over several areas of your yard, you should see the insects scurrying around after a few minutes. This YouTube video (1:59) explains how to do a soap flush: https://www.youtube.com/watch?v=sx_o4EMXsCo. Contact your Extension office for help with insect ID.
This technique is also a way to double-check what others suggest may be the cause. For fungal/disease problems, match the disease with the recommended fungicide.
And, don’t mistake irrigation problems with a pest infestation.
One of the easiest things you can do to take care of grass is to mow it at the right height and frequency, so as not to remove more than 1/3 of the grass blade at any time. Mowing too short can stress the grass. See Table 1 for the suggested mowing heights for Florida lawns.
Leave the clippings on the lawn because they provide nutrients and improve organic matter. They also provide free fertilizer. The nitrogen in grass clippings can replace one fertilizer application each year.
There’s another important practice to be aware of before summer rains: turn off or reduce your irrigation system if we get plenty of rain. This is one of the main causes of turf disease problems, such as take-all root rot, in the summer. This disease occurs when we start getting plenty of rain and we don’t adjust the irrigation system.
Grass needs ½-inch to ¾-inch water per irrigation event. If we get equal to or more than ½-inch to ¾-inch of rainfall, on top of irrigating the lawn one or two times per week, we put down too much water and create an environment for disease.
These disease problems can be hard to treat, sometimes requiring a year or more, and may result in costly replacement of dead turf and annual fungicide applications. Symptoms usually show up months after the summer rainy period, and at that point, they are very difficult to control. To avoid this problem, place an inexpensive rain gauge in your yard. Note the amount of rainfall received. Adjust your irrigation system if we get plenty of rain in a week. This simple strategy can significantly improve the health of your turfgrass and reduce disease potential.
Other tips for taking care of turf:
- Treat weeds and fertilize separately. Avoid using a weed-and-feed product.
- Remember, all Florida turfgrasses are dormant in winter. Resist the urge to fertilize in the winter when the grass is dormant. Not fertilizing in winter may improve turf quality the following year.
- Fertilize the lawn with a slow-release fertilizer. A good example is 15-0-15 with slow-release nitrogen, written as a percent on the back of the bag or the label. You want the first number on the bag (nitrogen) to be a 1:1 or 1:2 ratio with the last number on the bag (potassium). Potassium is a very important nutrient to keep grass healthy and to maintain its ability to withstand stress and disease.
A fertilizer with little or no phosphorous is OK, unless you have a soil test showing your soil is deficient in phosphorous.
- Fertilize your grass a few times per year. See each of these publications for information on yearly care and when to fertilize. Follow local ordinances where they apply.
St. Augustinegrass: https://edis.ifas.ufl.edu/pdffiles/LH/LH01000.pdf
For more information, check these references:
UF/IFAS Gardening Solutions Lawns Topic Page: https://gardeningsolutions.ifas.ufl.edu/lawns/
Central Florida Gardening Calendar: https://edis.ifas.ufl.edu/pdffiles/EP/EP45000.pdf
Optimal mowing heights for Florida lawns:
Bahiagrass: 3 inches to 4 inches
Bermudagrass: ½-inch to 1.5 inches
Centipedegrass: 1.5 inches to 2 inches
St. Augustinegrass: 2.5 inches to 4 inches
Zosiagrass (course types): 2 inches to 2.5 inches
Source: University of Florida/Institute of Food and Agricultural Sciences
Nicole Pinson is the Urban Horticulture Agent in Hillsborough County. Jan Ignash, UF/IFAS Extension Hillsborough County Master Gardener Volunteer, contributed to this column.
Published April 07, 2021