If you think the grass is always greener on the other side, then you may need to fertilizer your lawn.

Knowing the nutritional needs and what the baseline soil nutrient levels are both essential for producing not only a green lawn but a strong lawn.

Turfgrass requires 16 essential elements for their growth. The elements turfgrass require in the greatest quantities are nitrogen, phosphorus and potassium. These nutrients are obtained from the soil and absorbed by the plant roots.

Insufficient amounts of these nutrients in the soil limit the growth and quality, but can be added to the soil through fertilizer applications.

Soil testing should be performed to determine the amounts of phosphorus and potassium in the soil to see how much of each, if any, is needed to reach the recommended level. Nitrogen requirements cannot be reliably evaluated by a soil test. The type of turfgrass you have and the desired level of quality will determine the amount of nitrogen that should be applied.

Nitrogen affects your lawn’s color, density, leaf and root growth, tolerance to environmental stresses and its ability to recuperate after it has been damaged. It is the most important element applied to the lawn.

As with many cases in the garden when dealing with fertilizer, more is not always better. Excessive amounts of nitrogen will create leaf growth but at the expense of root growth and may cause a reduction in root mass. Remember, the roots pull the necessary nutrients from the soil so they need to stay healthy and strong.

Phosphorus is involved in energy transformation within the lawn. It is required in smaller amounts than the other two nutrients, but when establishing a lawn, it is critical. Most mature lawns do not require added phosphorus.

Potassium also affects turfgrass growth making it withstand environmental and mechanical stresses. Adequate levels of this element helps the lawn better tolerate cold, drought, and heat stresses.

The numerical formula that appears on just about any fertilizer refers to the percentage of the three macro-nutrients in that product. A bag that reads 16-4-8, for instance, contains 16 percent nitrogen, 4 percent phosphorus and 8 percent potassium.

To determine the amount of fertilizer needed to supply 1 pound of nitrogen per 1,000 square feet, divide the percentage of nitrogen, in this case 16, into 100. You would need to apply 6.25 pounds of 16-4-8 fertilizer to supply the proper nitrogen. (100/16 = 6.25)

Adding nitrogen

The following are the application rates of nitrogen per 1,000 square feet by month:

• Common Bermuda: Apply 1 pound in May, June and August;

• Hybrid Bermuda: Apply 1 pound in May, June, July and August. An optional 1 pound application can be applied in September;

• Centipede: Apply 1 pound in May and July; and

• Tall Fescue: Apply a half-pound in March; 1 pound in October and November and a half-pound in December.

When applying fertilizer, it is recommended that only half of the desired fertilizer be applied in one direction and then apply the remaining half across the lawn in the other direction. This provides a more uniform application and reduces the chance of missing a section.

Always apply fertilizer to dry turfgrass to reduce the risk of burning the grass leaves and water the lawn immediately after fertilizing. Be careful not to overwater to the point of runoff. This wastes fertilizer and pollutes waterways. Allow the water to soak into the lawn and soil.

Proper application of fertilizer will leave your neighbors green with envy. Until next week, happy gardening!

— Irland, a member of the Limestone County Master Gardeners, can be reached at kippirland@hotmail.com. For more information on the Limestone County Master Gardeners, visit http://mg.aces.edu/limestone.