Partial or complete yellowing of grass not only reduces the aesthetic appeal of the lawn, it indicates a health problem that requires immediate attention. Yellowing grass causes concern, especially since you have invested valuable time and effort on its establishment and maintenance. Several factors may be responsible for yellowing grass, including improper fertilising, dog urine, disease and fungal infections. Identify the cause immediately so you can amend the grass accordingly and help your lawn regain its original health and colour.
Soak the patch of grass with water immediately after you notice a dog urinating on it. The high nitrogen content in dog urine can burn grass, turning it straw coloured or yellow. Immediate action dilutes the urine and prevents the grass from turning yellow.
Provide your lawn with 2.5 cm (1 inch) of water every week to keep it from drying and turning yellow. An irregular watering schedule causes partial or complete yellowing of grass. Irrigating the soil deeply but infrequently prevents grass problems, including yellowing blades.
Inspect the lawn for diseases such as yellow patch and all patch. Symptoms of all patch include yellowing grass blades with brown roots and thinning of turf. In extreme cases, the grass patch comes out of the soil easily. Symptoms of yellow patch include 20 to 25 cm (8 to 10 inch) wide yellow patches of grass that occur in areas exposed to excessive shade and overly moist soils.
Inspect the yellow grass for lawn fungus that can lead to yellow spots in your lawn. If there's no other explanation for your lawn's yellowing, then fungus might be the cause. Treat infested grass with an approved fungicide from a nursery or garden centre.
Inspect the lawn for alternating green and yellow stripes of grass that indicate an uneven fertiliser application. To amend the problem, overlap wheel tracks when you fertilise the lawn with a drop-type spreader.
Direct traffic to another part of your lawn if you notice yellow patches of grass over areas foot traffic usually occurs. Heavy or frequent foot traffic compacts the soil, preventing moisture and oxygen from reaching the grass roots, causing it to turn yellow and limp before becoming brown. Aerate the soil every year to ensure that moisture reaches grass roots.