Common causes for lawn decline and July plant clinic

A Florida lawn can be frustrating. It is normal for a lawn to decline with time. When this happens, it is wise to take some time to attempt to determine the cause. Many times there are multiple causes.

Here is a list of some of the more common contributors to the decline of a Florida lawn.

Soil compaction – Mowing equipment, vehicles and foot traffic (from adults, children and pets) all result in the soil becoming compacted within a lawn. Compacted soil results in less water and oxygen getting to the lawn roots and less than favorable growing conditions for the roots.

Nutrient imbalances – Routine fertilization can result in some fertilizer elements building up to excessive levels while other elements may be lacking. It’s common to find high levels of phosphorus in older lawns. Phosphorus does not leach readily even in our sandy soils. Other elements such as potassium leach readily. Over time, we’ll end up with too much of some nutrients and too little of others, which contribute to growth difficulties and possible decline in our lawns.

Tree competition – Trees and larger shrubs can compete with a lawn. As a tree gets larger with time, it becomes more competitive with lawn grass. The tree’s demand for water and nutrients increases as it becomes larger. Its root area becomes more extensive and it progressively produces more shade. Lawns usually thin significantly in association with older, large trees and shrubs.

Root pests’ numbers may slowly build to damaging levels as a lawn ages. Some common examples include nematodes (microscopic roundworms), soil inhabiting fungi such as Gaeumannomyces and ground pearls (a scale insect found in soil).

Improper lawn maintenance practices may be a contributing factor in the decline of an older lawn. Common contributing factors to a lawn’s demise include routinely mowing too low, excessive fertilization and irrigating incorrectly.

Sometimes herbicides are only a “band aid” approach when dealing with an old, mismanaged lawn.

The following UF/IFAS Extension website link provides a wealth of information on growing a Florida lawn. http://hort.ufl.edu/yourfloridalawn

The July plant clinic will be held Friday, July 8 from 10 a.m. to 1 p.m. in Fort Walton Beach at the Okaloosa County Extension building, 127 W. Hollywood Blvd.

If you have a plant problem that you’d like diagnosed, bring a sample of the weed, plant, insect, etc., to the clinic. The sample should be fresh and represent what is seen in the landscape. This may include a plant stem with several leaves, a 4-inch square of grass with roots attached, etc.

You also may bring a sample of soil for pH testing.

Larry Williams is the Extension horticulture agent with the Okaloosa County Cooperative Extension Service, University of Florida. Contact Larry at 689-5850 or email lwilliams@co.okaloosa.fl.us.