How to Fertilize Bermuda Grass Lawns

Bermuda grass (Cynodon dactylon) forms a wear-resistant, attractive and low-maintenance lawn. Most varieties are hardy in U.S. Department of Agriculture plant hardiness zones 7 through 10. On the down side, Bermuda grass spreads easily and is considered invasive in some areas, such as California wild lands. Before planting the grass, consult with your local agriculture department or department of natural resources. After planting, Bermuda grass lawns require some regular fertilization to stay healthy and attractive.

Fertilizer Timing

Bermuda grass generally only needs fertilizer during its growing season in spring and summer. During late fall and winter, the grass is dormant and does not require fertilizer unless the soil has a deficiency or the grass has been overseeded. Wait to start fertilizing until the grass turns green and begins growing again in the spring. Depending on the local climate, it may come out of dormancy in March or April. During June, you will switch from a complete fertilizer to a high-nitrogen one.

Type of Fertilizer

For a precise recommendation on the specific amounts of each nutrient a Bermuda grass lawn needs, you can get a soil test kit from a garden supply store. In the absence of soil testing, use two types of fertilizer for Bermuda grass. During the spring, when the grass turns green through May, use a complete fertilizer with more nitrogen than potassium and phosphorous. For example, a 3-1-2 or 4-1-2 ratio fertilizer will work well to promote green growth. During summer -- June through August -- use a high-nitrogen, low-phosphorus fertilizer or a nitrogen-only fertilizer. Examples that work well are products with a 21-0-0 or 21-3-6 ratio.

Applying Fertilizer

For small spaces, you can carefully sprinkle fertilizer evenly by hand. For larger lawns, a commercial fertilizer spreader makes even distribution easier. Determine the ideal fertilizer application rates by calculating the amount of nitrogen per square foot of lawn space. During the spring, apply 1 pound of soluble nitrogen per 1,000 square feet of lawn every four to six weeks or 1.5 pounds of slow-release nitrogen every eight to 10 weeks. During summer, apply 1 pound of nitrogen per 1,000 square feet every four to 10 weeks. To calculate how many pounds of a fertilizer will give you 1 pound per 1,000 square feet, divide 100 by the first number in the fertilizer ratio. For example, if using a 3-1-2 ratio during spring, you would calculate as follows:

100/3 = 33.3 pounds of fertilizer per 1,000 square feet of lawn

For a 21-0-0 ratio during summer, you would calculate:

100/21 = 4.76 pounds of fertilizer per 1,000 square feet of lawn

Additional Care

Bermuda grass generally does not need fertilizer in the fall or winter. If soil tests reveal a potassium deficiency, however, you may apply 1 pound of potash per 1,000 square feet in September. Overseeded Bermuda grass should receive 1/2 pound of nitrogen per 1,000 square feet in December and again in February. If you mow a Bermuda grass lawn frequently so that you remove less than one-third of the total grass blade height with each mowing, you can leave the clippings on the lawn. They will add additional nutrients to the soil as they degrade and will not clump up if cut often enough.