The principal problem with growing grass on Galveston Island is the soil. Galveston Island is one of a number of barrier islands along the Gulf of Mexico and is basically a 24 mile long sand bar.
Improving an existing lawn and starting a new lawn are two different problems. Sand burrs grow easily and naturally in the sand of Galveston Island. Grass does not seem to grow either naturally or easily.
If you are starting a new lawn the most important thing you can do is amend the soil as much as possible with organic matter. This will provide both increased fertility, and most importantly, will assist in retaining moisture. Even after improvement with organic matter you are still working with a base that is pure sand. Sand does not hold moisture well and nutrients leach out of the soil quickly.
You may actually have to do a little experimentation over time to determine the correct amount of fertilizer to apply and the frequency of application for your lawn. In my case I have found it best to lightly fertilize twice as often as the general recommendations for the greater Houston area. One can also supplement the use of a balanced fertilizer with nitrogen between feedings, using ammonium nitrate, ammonium sulfate or urea for the nitrogen source. The best defense against sand burrs is in improving the soil. They seem to thrive in the poorest sandy soil and cannot compete when watered and fertilized often.
The general advice of applying enough water to wet the top 4-6 inches of soil or about 1/2 to 1 inch of water across the lawn also has to be modified for the sandy soil of Galveston. Sandy soil absorbs water at a much faster rate than finer textured soils but retains much less moisture. A more practical recommendation is to water twice as often using half as much water as the general recommendation. When a lawn requires water it will respond by beginning to discolor and wilt. Also, if tracks remain after walking across the lawn, this is a good indication that it needs water.
Water in the early morning if at all possible. Winds are lighter and temperatures are lower minimizing loss to evaporation. Late afternoon is the worst time to water.
Beautiful lawns can be grown in the sandy soil of Galveston Island but it does take work and is a continuing challenge.