Where do you live?

What kind of grass do you have?

That's a big area to miss with fertilizer unless you were throwing it by hand. What is your watering schedule? How often and for how long do you water?

I live in Houston Tx. I water every other day, 2 cycles of 8 mins per cycle

I'm going to say that improper watering is the problem. You can correct that right away.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

One purpose of deep watering is to force the roots to grow deeper into the soil. With your watering you might have roots as deep as 3/4 inch (for example). That volume of soil is 2.3 cubic yards. With deep watering you'll get roots down to 3 inches or more. That's 9.3 cubic yards of soil. Without doing anything but changing your watering, the grass will start getting nutrients from much more soil than the way you're watering now.

I live in Bandera (in the Hill Country 40 miles NW of San Antonio). We've had 1/2 inch of rain in the past 2 months. Daytime temps are running in the 80s. At the beginning of May I thought I would go into June without watering, but we got several days of sun and low humidity. That caused me to water the back (sloped to the south), but not the front. Here's a picture of my front yard which has been watered once this year.

It is St Augustine most of the way out to the sago palm and prairie grass (weeds) beyond that. The important thing is the color and the fact that it is dense after having been watered only once this year. Oh, and I have not fertilized in the past 12 months, so you're not seeing a fertilizer effect. This is Memorial Day weekend, so I'm planning to fertilize with the bin of alfalfa pellets in the garage. Anyway change to deep, infrequent watering and your lawn should look much better.