When it comes to choosing lawn fertilizer, understand that there are four basic categories of fertilizer, and a multitude of specific types within each category.
There are liquid fertilizers, dry fertilizers, fertilizer made from synthetic materials, and fertilizers that are all organic.

The reason that there are so many types is because the many different climates and grass types found throughout the world demand a wide range of diversity to be effective in maintaining healthy, vibrant yards. 
Fertilization directly correlates to temperature, rainfall, speciation, and soil content.  As such, it must be methodically selected and carefully applied. 

Many people prefer to apply their own lawn fertilizer because to them it is a simple task that also gets them outside during the burgeoning spring weather. 
We completely support this, provided the client chooses and applies the right fertilizer and applies it correctly.  Many Houston properties have basic San Augustine yards that really only need a little boost three to four times a year.  Residents of these properties may want to save money on fertilization and invest it in something more significant such ascustom gardens, patio design, or landscape architecture.   

Even so, the application of lawn fertilizer must be done systematically in timed cycles.  The first cycle begins when the soil warms in the spring and roots begin to grow.
In most parts of the United States this occurs sometime during April or May.  In Houston, however, our much warmer climate often witnesses early growth spurts depending on how soon consistently warm weather shows up.  This can happen as early as mid-March, so do not rely upon what books or generic websites give in terms of advice. 

Think about our local climate, and if you have any questions, call your landscape professional before assuming that a fixed date on the calendar is the day to begin taking care of your yard.   

This is necessary for two reasons.  The first of these is the stimulation of plant growth.  Roots need nutrients to maximize their spring growth spurt.  Secondly, roots need nutrient reserves to protect them during the hot Texas summer months. 

Many products are designed to fertilize a lawn and also kill insects and fungi.  People are drawn to these products because they offer the equivalent of a one-size-fits-all solution.
We hesitate to either endorse or denounce any product.  However, we do caution our clients not to be carried away by quick fix claims or anything that appears to be so easy that you do not even have to think about what you are doing.  In many cases, such products fall far short of their anticipated results.

The best thing to do before buying any such product is to call your landscaper and discuss the product ingredients, instructions, and claims before using it in your yard. 

You can also include lawn fertilizer services in a landscape maintenance plan.  This plan also takes care of insects and fungus with chemicals specifically chosen with your yard in mind.
For yards that have multiple grass species that figure prominently in Houston landscape design, we will come out anywhere from four to five times a year.  For smaller yards with only one species of grass, two or three times a year maximum may be all that is required.