Managing a healthy St. Augustine lawn
If the trend continues, 2017 is the year of St. Augustine for me. Almost all of my lawn questions concern this gorgeous, dark green, wide-blade grass. Like Bermuda, Zoysia and Centipede grass, St. Augustine is also a warm season grass. It grows from southern Florida into Georgia. It does not do as well in north Georgia with colder temperatures.
I’ve seen the best and worst of St. Augustine grass this season. This prompted me to write an article about the best management practices for your St. Augustine lawn. This column is not to expound on “what the book says,” but instead my experience. And believe me, I have lots of experience!
When you are around a conversation concerning lawn management, most people talk about what needs to be sprayed, how much to use, etc. Believe it or not, the textbooks talk more about cultural practices — mowing, watering, fertilization — than what needs to be sprayed. I learned firsthand that more than half the success of a beautiful St. Augustine lawn results from solid cultural practices. (The other half comes from rain.)
Let’s start with the soil: When you go to Disney World, you see lots of St. Augustine grass driving through Florida. This grass grows in a very sandy environment. It loves a soil with good drainage. But doesn’t every species of grass? So in a way, it’s not fair to talk about “good soil drainage.” Nonetheless, it is important. If you see yellow, thin, St. Augustine in “mushy” lawns, it’s too wet!! There is no oxygen for the roots. The good news is that most of our lawns do not struggle with this issue.
Continuing on the topic of soil, let’s talk about fertilization. This is a very important cultural practice. In centipede, we do not want to use lots of fertilizer. This is not the case with St. Augustine. With St. Augustine, we want to pour it on. It likes three times more nitrogen than centipede. And, it is OK to use a fertilizer ration with a higher percentage of nitrogen. Remember, nitrogen is the first number on the bag of fertilizer. For instance, a 50-pound bag of 16-4-8 contains 16 percent nitrogen, 4 percent phosphorus and 8 percent potassium.
How much fertilizer do you put out? Easy! Do a soil test! There is a lot of math involved. So why not take an inexpensive, $6 soil sample of the front yard and back yard (separately) and fertilize based on the recommendations? The recommendations provide a few different fertilizer options (e.g. 12-4-8 or 10-10-10) and the rates which you should use. It will also tell you how many times a season to apply it.
Another important cultural practice is mowing. Some of us mow our lawns so we do not get in trouble with the neighbors. Remember Jeff Foxworthy’s idea? “I like for my grass to grow so tall (that) nobody knows a house is there!” That may be OK for security reasons. In any event, St. Augustine likes to be cut high as well. If you cut your St. Augustine less than three inches, it will not look good!
St. Augustine needs to be cut between three and four inches. Some of you will say, “That doesn’t work. My kids want to play in the yard.” Centipede grass is a much better choice for playing ball in the yard and cutting the grass short (one to two inches is recommended for centipede.) If four inches sounds tall, notice St. Augustine driving through Orlando to Disney World. It stands nearly six inches in those medians. A small dog could hide in that grass.
I have personally observed a routinely, two-inch mowed St. Augustine lawn overcome by stress. Even if it had plenty of water, the grass still appears yellow. This allows stress from insects and disease to be much worse.
The final cultural practice is one we are all benefiting from now. That is water! St. Augustine needs water. Rain is always going to make your lawn look better than irrigation. This is why it is important to understand that irrigation only supplements rainfall. Former UGA peanut agronomist Dr. John Baldwin always said, “If it don’t rain, it don’t matter.” What a profound statement from a PhD scientist ….
Dr. Baldwin’s comment is actually in reference to fertilization, but it is still true of the benefits of rain. There is no reason you should have watered your lawn more than two times this past two months. One hundred percent of St. Augustine samples brought to my office this season had active Take-All Root Rot. This is the most damaging disease of St. Augustine and is only present when the grass is wet.
Remember, when our rain is “normal” or “less-than-now,” we want to water our St. Augustine one inch per week, one time per week apart from rainfall. If you water every three days, you might as well go ahead and plan for fungicide applications, too. St. Augustine needs water, but heavy irrigation events accomplished infrequently are recommended.
For more information, contact the Thomas County Extension office at 225-4130.