ONE GARDENER TO ANOTHER: Maintaining healthy lawns with fertilization

Kipp Irland For The News Courier

This week’s question comes from reader Ed G., who asks, “How do I get a lush, green lawn like my neighbor, who uses a lawn company?”

If you think the grass is always greener on the other side, then you may need to fertilize your lawn. Knowing the baseline soil nutrient levels and the nutritional needs of turfgrass are essential for producing not just a green lawn, but a strong one.

Turfgrass requires 16 essential elements for their growth. The elements turfgrass requires 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 growth and quality. However, they 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 turfgrass, it is critical. Most mature lawns do not require added phosphorus.

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

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

To determine the amount of fertilizer needed to supply 1 pound of nitrogen per 1,000 square feet, divide 100 by the percentage of nitrogen — in this case, 16. You would need to apply 6.25 pounds of 16-4-8 fertilizer to supply the proper nitrogen. (100/16 = 6.25) To find square footage, multiply the length by width of the area. (For example, a plot 45 feet in length and 22 feet in width is 990 square feet.)

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 both October and November, and a half-pound in December.

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

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.

Working hand in hand with a fertilization program are a few easy but important practices to keep lawns lush and green, including mowing no more than 1/3 the height at one time, mowing with a sharp blade to reduce damage to grass leaves and keeping on top of weed removal to reduce competition for nutrients, water and sunlight.

Proper application of fertilizer, along with good lawn practices, will leave your neighbors green with envy!

Until next week, happy gardening.

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