Yellowing of Grass

Pests

Although the variety of pests damage lawn grass differently, the end result is a flat, limp and yellow patch of grass that stands out against the surrounding green grass. Chinch bugs, mites and grubs are examples of pests that sap juices from grass blades and chew on roots. Treat infected parts of the grass with a registered insecticide, and keep foot traffic off the lawn until the treatment shows results. In case of extreme damage where the grass has no chance of recovery, rake yellow grass out of the soil and reseed the area.

Following an untimely or erratic irrigation, fertilization or mowing schedule increases stress on grass, causing it to appear yellow and increasing its susceptibility to pest damage and disease. Adopt a regular maintenance schedule to keep your lawn grass healthy. Instead of frequent, light irrigation that increases the chance of fungal diseases, water your grass deeply, but infrequently, using a soaker hose. Avoid watering your grass in the evening or night as it increases the risk of contracting fungal diseases. Fertilize your lawn grass with 1 lb. of nitrogen fertilizer per 1,000-square-foot area. Keep your lawn grass mowed down to between 2 to 3 inches. During the summer, however, mow it slightly higher than the recommended height to reduce stress and dehydration.

Fusarium patch, dollar spot and rust are diseases that cause lawn grasses to turn straw-colored or take on a yellow appearance. Because the fungal diseases appear on stressed grasses, adopt good cultural and sanitation practices to help strengthen your lawn so it naturally wards off fungal spores. In case of extreme infestations, treat grass with a registered fungicide according to label directions to help it regain its natural color.

Other factors responsible for yellowing grass include dormancy, physical damage, dog urine and iron deficiency. Frequent foot traffic causes soil compaction that prevents water, nutrients and sunlight from reaching the base of grass plants and roots, thus causing the grass to turn yellow. Frequent dog urine over the same spot causes yellowing grass because of the high concentration of nitrogen it contains. Grass that grows along concrete sidewalks or walkways usually turns yellow because the high-alkaline content of the hardscaping absorbs iron in the soil, depleting reserves for grass.