In spring, the optimal time to apply an herbicide is mid-February.  The optimal time to apply the optional feeding is mid-April.  And in fall, one should apply herbicides mid-September and fertilize mid- to late-October. 

     The buyers for the big-box merchants or corporate clone nurseries must be horticultural morons.  Leave the weed and feed on the shelf and select the correct product instead.  Your grass will thank you.

     The optional spring fertilization of grasses in central and south Texas should not take place until mid-April (south of San Antonio) to mid-May (Hill Country).  Feeding too early, before the grass can use nutrients, is, at best, a waste of resources.  At worst, premature feeding will  cause a flush of weed growth and encourage the spread of disease-causing organisms.
     The best slow-release fertilizers for this area are 3-1-2 ratio products with "polyon" encapsulation of nutrients.  The old-fashioned "sulfur-coated urea" products, even those labeled as premium formulations are not as good.
     Never fertilize Buffalograss.  Feed Zoysia only every other year in the fall.
St. Augustine grass requires only fall feeding.   Bermudagrass grown as a utilty turf should be fed mid-April and mid- to late-October.  If you want greener grass, apply Ferromec, as needed, mid-March to mid-September.

     Please, do not apply "winterizing" fertilizers before grass has become dormant in October.  Feeding too early causes a flush of growth and does not promote the storage of nutrients which is desired.
     Big-box retailers and corporate clone nurseries sell "winterizing" fertilizers which do not contain a 3-1-2 ratio of nutrients, as recommended by university turf experts in Texas.   The numbers mean 3 parts of nitrogen to 1 part of potassium to 2 parts of phosphorus.  Fertilizers with a 3-1-2 ratio of nutrients include:  15-5-10 and 21-7-14.
     Never fertilize Buffalograss.  Feed Zoysia only every other year in the fall.  St. Augustine grass requires only fall feeding.  Bermudagrass grown as a utilty turf should be fed mid-April and mid- to late-October.

     Watch out for inflated claims of coverage for fertilizers.   For example, if one wishes to apply the recommended one pound of actual nitrogen per 1000 square feet, a 20 pound bag of 15-5-10 will cover only 3000 square feet.  15% of 20 pounds = 3 pounds, at rate of 1 pound per 1000 square feet, the coverage is 3000 square feet.