How to Cure Yellow Grass

Aerate lawns that are mostly green with streaks of yellow. The iron in the soil in such lawns is not readily available to the grass, which has become malnourished and turned yellow. After aerating, top the grass with a 1/3-inch layer of compost and water it in. This will help strengthen the grass roots and provide it with iron, greening up the yellow streaks.

Spread the seed of a grass that is resistant to St. Augustine grass, such as Raleigh, if your grass has splotches of green and yellow. St. Augustine decline virus weakens the grass, causing splotches of yellow. The resistant grass will spread and overtake the weaker grass, curing the problem.

Check for circles of brown, dead grass rimmed with yellow. This indicates an insect problem. Look for the insects in the yellow grass. Bring an example to your local county extension office for identification and advice regarding treatment.

Look for "frog's eye" patches of yellowed grass. This is a ring of yellow around a green center, which is caused by rhizoctonia cerealis, a fungus common in cold, wet areas. It especially affects Kentucky bluegrass. The patches may grow to two feet in diameter. To cure this fungus, aerate the law to break through thatch and increase drainage. Change your watering schedule so that you water lightly and frequently. It is important to avoid standing water or heavy, wet soil.