Fertilizer supplies essential nutrients to the grass plant for adequate growth and maintenance of plant functions. If you want to have a quality lawn then some fertilizer is key. Different turfgrass species require different amounts of fertilizer and they all need to have the fertilizer at a consistent rate - by this I mean don't put down all of the required fertilizer for the year at one time because the plants cannot use it all then and most of it will be lost to leaching or move off-site with rain or soil particles.
The key is to supply adequate amounts of essential nutrients (we base our recommendations on nitrogen because it is needed in the highest quantities by grass plants) throughout the growing season from April through September in amounts that can be fully utilized by the turf.
How much Nitrogen per thousand square feet per year
Buffalograss - 2 pounds
Centipedegrass - 2 pounds
Common Bermudagrass - 4 to 5 pounds
Hybrid Bermudagrass - 5 to 6 pounds
Kentucky Bluegrass - 4 to 5 pounds
St. Augustine - 4 to 5 pounds
Tall Fescue - 4 to 5 pounds
Texas Bluegrass - 4 to 5 pounds
Zoysia japonica (coarse bladed) - 2 to 3 pounds
Zoysia matrella (fine bladed) - 3 to 4 pounds
A good schedule to follow for Bermudagrass, Zoysiagrass and St. Augustinegrass is the "Major Holidays Rule" - Divide your total nitrogen requirement for the year by four. Put down this rate of nitrogen on or near each of the four holidays: Easter, Memorial Day, 4th of July, and Labor Day. If you follow this - you will be doing very well.
Centipedegrass and Buffalograss should not be fertilized more than twice a year. The bluegrasses and tall fescue will need fertilization spaced over the entire year because they will maintain active growth through much of the winter.
Selecting the right fertilizer
Most fertilizers are similar and what you really need is nitrogen. You can shop around by finding the cheapest price per pound of nitrogen. When you look at a bag of fertilizer, there are three numbers separated by dashes, which is called the "analysis" of the fertilizer.
It is actually a percentage of Nitrogen, Phosphorous, and Potassium, which are the three nutrients in highest demand by the grass plants. Nitrogen is the first number, then Phosphorous, then Potassium (N - P - K). You can compare the price per pound of nitrogen taking the first number (for example we'll use 15) and divide by 100 for the decimal equivalent of the percentage (0.15). Now multiply this by the total weight of the bag (40 pounds) for the number of pounds of nitrogen in the bag of fertilizer (0.15 X 40 = 6 pounds of nitrogen).
Now take the total price for the bag of fertilizer and divide by the number of pounds of nitrogen to get price per pound of nitrogen ($15 price / 6 pounds N = $2.50 per pound of nitrogen). Compare with other bags of fertilizer.
Phosphorous and Potassium are also important and it would be very helpful to buy a fertilizer with some of these nutrients included, but you can use a product like ammonium sulfate (21 - 0 - 0) or urea (46 - 0 - 0) for most of your fertilizer needs unless a soil test report shows that the other two nutrients are low in your soil. In many Texas soils, phosphorous is already at high levels and adding more from your fertilizer could actually cause problems.
