A landscape problem that very possibly will appear this spring is the yellowing of turfgrass.

I suspect, considering the wet conditions experienced lately, combined with the abundant moisture received last fall and winter, that iron chlorosis will be problematic in some area St. Augustine lawns.

Excessively wet soils can cause a reduction of iron uptake in various turfgrass species.

In addition to wet and cool conditions, a chlorotic look can also be due to compacted soils and soils with high pH.

High levels of soil phosphorus may lead to deficiencies in iron as well.

Therefore, lawns that have received excessive amounts of fertilizer high in phosphorus may experience an iron chlorosis problem.

Iron chlorosis results when green chlorophyll in leaf tissue fails to develop.

Although iron is not part of the chlorophyll molecule, it is one of the nutrients essential for chlorophyll synthesis.

When iron chlorosis first appears, turfgrass leaves are yellowish-green in color, giving the leaf a striped appearance.

This striping is due to an interveinal yellowing, As the condition worsens leaves appear almost white in color.

Regardless of the cause, iron chlorosis can be corrected by applying iron sulfate or iron chelates.

These products can be obtained wherever lawn and garden supplies are sold.

In alkaline soils, foliar applications are more effective since soil-applied iron is tied up quite rapidly and its availability to the plant is limited.

Follow up applications may be required to restore a bright healthy green color. Caution should be used when spraying iron solutions.

Any over-spray may leave rust stains on sidewalks, bricks, and clothing.

Making adjustments in irrigation practices during periods of abundant or excessive moisture will help soils from becoming excessively wet.

Improving nutrient management practices will limit future iron chlorosis problems brought about by excessive fertilization applications.

Utilizing a soil test to determine the type and the amount of fertilizer needed insures that phosphorus is not allowed to build up to extremely high levels.

Also, aerating compacted soils will provide some relief, since compaction prevents adequate gas exchange, moisture penetration and nutrient movement.