Grass Is Turning Black After Fertilizing

Fertilizer Burn

• All plants require a careful balance of soil nutrients in order to grow healthily, and each plant has its own ideal nutrient balance that differs from other plants'. If this ideal balance does not already naturally exist in the soil, fertilizers and other soil amendments are used to change the nutrient balance and to bring it closer to the ideal. Balance is the operative word in understanding this concept; either too little or too much of any of these nutrients can cause deleterious effects in plant growth. If you add too much fertilizer to a given soil, the plants growing above that soil can take on a burned appearance as a result of the nutrient imbalance.

Symptoms

• The symptoms of fertilizer burn vary among different plant species. In lawns, homeowners will often notice large patches of discolored grass that cannot be reasonably attributed to any other ailments. Often, these patches will be in a striped pattern reflecting the areas where a spreader was used to apply the fertilizer. In areas where the spreader turned to double back on a new row or where new fertilizer was added, patches may be more severely burned due to the excess amount of fertilizer left on that patch of lawn.

Treating a Burned Lawn

• Unfortunately, there is no quick-fix solution to a lawn that has been burned by fertilizer misuse. This is unfortunate, since fertilizer burn can easily lead to other lawn health problems, such as fungal diseases and insect infestation. The most important thing you can do to alleviate fertilizer burn is to maintain good cultural practices to keep the lawn in good health. So long as your lawn is healthy and vigorous enough, it will outgrow the damage caused by fertilizer burn.

Preventing Fertilizer Burn

• But of course, allowing your lawn to outgrow damage is only half the battle. Having identified fertilizer burn as the cause of the browning, it is necessary to adjust your fertilization practices to avoid future problems. If you use a quick-release fertilizer on your lawn, be sure to water it in after use and avoid applying it in hot weather, as these are two of the most common causes of fertilizer burn. Most importantly, use only the smallest amount of fertilizer necessary to achieve the ideal nutrient balance for your lawn grass.