Reasons for the Grass Turning Brown When Over-Fertilized

Fertilizer Burn from Salt

One of the causes of fertilizer burn is the salt in the fertilizer. Excess fertilizer applied to lawns leads to excess salt on the surface of the soil. The chemical buildup that results from salt on the lawn dries out the soil and takes moisture away from the roots of the grass and the blades themselves, leading to brown or yellow grass that takes on a burned appearance. Apply fertilizer according to the directions.

Nitrogen is a key chemical for lawns; it provides the grass with an essential nutrient and helps give grass its dark green, healthy appearance. However, using the right type of nitrogen is important. While quick-release nitrogen is a good chemical for getting grass to turn dark green quickly, it is also more likely to burn the grass by overwhelming the soil. Watering heavily after fertilizing the lawn reduces the chances of nitrogen burning the blades.

According to the Clemson Cooperative Extension website, the type of fertilizer affects whether it is more or less likely to burn the lawn when applied. Inorganic fertilizers are made of synthesized or artificial chemicals, while organic fertilizers contain ingredients derived from natural sources like compost or manure. Inorganic fertilizers have a greater likelihood of causing burn on lawns, and applying during cooler portions of the day and watering heavily is important for avoiding problems with burn.

Fertilizer burn is sometimes caused by inattention to the method of applying fertilizer. Some fertilizers are spread over the ground with a spreader to create an equal application that avoids patches of chemicals that lead to burn. Spray fertilizers require a tool to keep the amount of spray even; avoid spraying the same area of the lawn more than necessary, as this excess application leads to burn. Follow all directions when using fertilizer to prevent the lawn from suffering avoidable damage.