My St. Augustine lawn is not as thick as it once was. The trees have grown larger, and it is shadier. What can I do to make the lawn thicker?  If shade is causing the thin lawn, there is not much you can do. Even St. Augustine grass requires 4 to 5 hours of sun to prosper. Have you fertilized? Use a slow-release lawn fertilizer such as 19-5-9 every spring about May 1, or now, and again in the autumn about Oct 1. Enjoy the shade and ignore the thinning lawn.

Our tomatoes are growing strong and have set some fruit, but the peppers are not growing. We have fertilized, and the garden is in full sun. Is there an issue you can think of? I think everyone’s peppers are reacting the same way to the relatively cool weather. They require more heat than tomatoes. Be patient.

 We have the caterpillars that hang from the string in our live oaks this year after having a few years without them. Is it still your opinion that they do not need to be sprayed?  Yes, the live oaks seem to recover quickly without any lasting negative results from infestations, so treatment does not seem necessary.

What is the name of the vinca variety that does not seem to be susceptible to aerial phytophera? They are attractive, and do not turn to mush if it rains. The variety name is Cora.

Our summer squash is already infested with squash vine borers. What preventative treatment should we have used? Is it too late to reseed and start over?  To control squash vine borers, apply carbaryl to the growing point every week. Thiodan was the original insecticide used but is no longer available. If the weather cooperates, you may still be able to raise a new set of plants.

What are some different options for high-quality shade trees? We have live oaks, Texas red oaks and cedar elms. Consider Mexican sycamore, Chinese pistache, Montezuma cypress, Chinkapin oak, Mexican white oak, Lacey oak and or bur oak. All do well in our area and produce long-lived, high-quality shade trees.

Dr. Calvin Finch is Urban Water Program Director for the Texas A&M Institute of Renewable Natural Resources.You can ask Calvin question and hear his answers on the air as he co-hosts the Gardening South Texas on the air at KLUP (AM 930) Saturday and Sunday from 12:00 to 2:00pm.