What can I use in my St Augustine lawn to get rid of nut sedge?

Hi. It's a little late in the season, so start in the spring. Use a pre-emergence. These are typically found in a weed and feed sold at the big box stores. It's best to follow a St. Augustine program. Get one from the local agricultural extension service. Good luck.

Check with your local nursery.

Your local County Extension Agent will have good information for you regarding the grass and best time to do what. Also, will have info about other gardening in your particular area. They are an excellent source. Look in government section of your telephone directory.

Since St. Augustine is a grass (and not a broadleaf), 2,4-D will not kill it. ... see less2, 4-D is a generic broad leaf weed killer found in almost all broadleaf herbicides. Since St. Augustine is a grass (and not a broadleaf), 2,4-D will not kill it.