When do I fertilize my lawn?

When to fertilize…The best way to know exactly what fertilizer to use is to perform a soil test.  A professional lawn care provider will usually collect a soil sample in February or early March in order to determine which fertilizer ratio will provide the needed macro and micro nutrients.

We are going to look at the fertilization process for each of the common East Texas turfgrasses. If you have any questions be sure to Contact Us by phone or email.

Fertilizing Zoysia Grass

Established zoysia grass requires less fertilizer than many other species for healthy, attractive turf. A seasonal total of 2 pounds of nitrogen per 1,000 square feet is ample. Excessive or untimely fertilizer applications can lead to problems such as fewer roots, more thatch, diseases, and more topgrowth that requires increased mowing.

For best results, soil testing is recommended before fertilizing. A soil test will indicate major nutrient deficiencies and the acidity or alkalinity (pH) of the soil. Slightly acidic soil pH (6.0-6.5) is best. Lime should be applied only if the pH is less than 6.0.

Established Zoysia grass should be fertilized from May through August. Early spring (March/April) fertilization benefits weeds and promotes premature topgrowth before roots begin to grow. Late fertilization (September) may interfere with the natural hardening process before winter.

For routine maintenance where soil tests indicate no major deficiencies, use a lawn fertilizer with approximate nitrogen (N):phosphorus (P):potassium (K) ratio of 3:1:1 or 4:1:1 or 4:1:2. A 16-4-8 fertilizer has a 4:1:2 N:P:K ratio.  Where soil test indicates low phosphorus or potassium levels or where basic fertility levels are not known, use a fertilizer with a ratio that more closely approximates 1:1:1 or 2:1:1.

Bermuda Grass

Bermudagrass will start to grow and turn green when the soil can maintain a temperature of 65 degrees.

Begin fertilizing after the grass turns green and there is little chance of a late frost. Have the soil tested to determine what nutrients your lawn needs. For information on soil testing procedures, contact your county Extension agent or use a professional Lawn Care company. 

If you do not have the soil tested, use a complete fertilizer with a 3-1-2 ratio of nitrogen, phosphorus and potassium (Examples: 15-5-10, 21-7-14, etc. Every bag of fertilizer has the nutritional analysis printed on the bag). Apply 1 pound of soluble nitrogen per 1,000 square feet of lawn every 4 to 6 weeks, or 11/2 pounds of slow-release nitrogen fertilizer every 8 to 10 weeks. To determine the amount of fertilizer to apply to equal 1 pound of nitrogen per 1,000 square feet, divide 100 by the first number in the fertilizer analysis. (To determine the amount needed to apply 1.5 pounds per 1,000 square feet, substitute 150 for 100.) For example, if you are using a 15-5-10 fertilizer, then 6.6 pounds of fertilizer per 1,000 square feet will be needed. 100 15 = 6.6 Then determine the size of the area to be fertilized. If your lawn is 5,000 square feet, it will need 33 pounds of 155-10 fertilizer. (5,000 Watering 1,000) x 6.6 = 33 pounds of fertilizer.

Centipede Grass Fertilization

Proper fertilization of centipedegrass is important for plant health. Phosphorous and lime applications should be based on soil test results. A common mistake is to fertilize centipede grass too early in the spring. The first, or spring, nitrogen application should not occur until soil temperature at the 4-in. depth is consistently 65 °F. Also, it is not uncommon for centipedegrass to be overfertilized. One pound of nitrogen per 1,000 square feet per year is ample nitrogen for most established centipede grass lawns. Ideally, a centipedegrass lawn would be fertilized either three times during the year with 1/3 lb of nitrogen per 1,000 square feet or four times during the year with 1/4 lb of nitrogen per 1,000 square feet. On sandy soils in high rainfall areas, 2 lb per 1,000 square feet applied during the year may be needed.

If the grass shows signs of iron chlorosis (yellowing of leaves), apply ferrous sulfate at the rate of 1 tablespoon per 3 gallons of water to each 1,000 square feet of grass. Applications of iron will only temporarily darken the green color of centipedegrass and may need to be applied every two to four weeks. Chlorosis can also be a symptom of more permanent problems like improper soil pH and an elevated level of soil phosphorus. A soil test can confirm the cause of centipede grass yellowing.

When do I fertilize St. Augustine?

St. Austine grass will start to grow and turn green when the soil can maintain a temperature of 65 degrees.

Typically, you would begin fertilizing 3 weeks after the grass turns green and when there is little chance of a late frost. Apply 1 pound of soluble nitrogen per 1,000 square feet of lawn every 8 weeks, 1 ½ pounds of slow-release nitrogen every 10 weeks. Have your soil tested to determine what added nutrients your lawn may need. For information on soil testing procedures, you can contact your county Extension agent or, use a professional Lawn Care company. 

If you do not have the soil tested, use a complete fertilizer with a 3-1-2 ratio of nitrogen, phosphorus and potassium (Examples: 15-5-10, 21-7-14, etc. Every bag of fertilizer has the nutritional analysis printed on the bag).  To determine the amount of fertilizer needed to equal 1 pound of nitrogen per 1,000 square feet, divide 100 by the first number in the fertilizer analysis. 

For example, if you are using a 15-5-10 fertilizer, then you need 6.6 pounds per 1,000 square feet. (To determine the amount needed to apply pounds per 1,000 square feet, substitute 150 for 100.) 100 15 = 6.6 Then determine the size of the area to be fertilized. If your lawn is 5,000 square feet, you will need 33 pounds of 15-5-10 fertilizer. (5,000 Watering 1,000) x 6.6 = 33 pounds of fertilizer.

Given these points…

You can see that each of the common turfgrasses has their own fertilizing needs. As you can see, what works for Zoysia may not be good for St. Augustine. It is best to have a soil test to know what fertilizer would be best for your situation.