You’re a dedicated homeowner who care about your lawn; that’s why you’ve fertilized it. If you’ve found brown spots after doing so, you’re probably feeling a little discouraged. Why has your lawn’s quality degraded since you tried to care for it, and what can you do about it? Here’s what you need to know if your lawn has developed brown spots after being fertilized.


If these brown spots have popped up on your lawn just after you’ve put fertilizer on, it’s most likely that the fertilizer is the cause. Your fertilizer should have an ideal mix of essential plant nutrients: nitrogen, phosphorus, and potassium. Many fertilizers also have soluble salts in them, and these can actually burn the grass and leave it brown. This is especially common for quick-release fertilizers. If you spilled the fertilizer or applied too much in certain areas, then you could get brown patches in your grass.

If you spot browning after fertilizing, you can take steps to reduce the damage and help you grass get back on track. Your first step should be to rinse the lawn immediately and very thorough. Then, every day for a week, flush the lawn as fully as you can. Stop after a week so as not to drown your lawn. In a few weeks, the brown areas should start to turn green.

You may need to reseed areas that were too heavily damaged by the fertilizer. Large brown gaps will fill in from the edges, but pretty slowly. It’s best to just reseed these spots.

Other Causes of Brown Spots

So, you flushed out your lawn, and that didn’t help remove the brown spots. In fact, it may have even made it worse. What do you do now? It’s possible that the fertilizer was only a coincidence and something else is going on with your lawn. Other causes of brown spots include:

  • Fungal infections: A fungal infection can turn your grass brown. It will appear as patches of brown grass, often in humid weather. Too much water, humidity and poor airflow can encourage fungal growth. In order to control the fungus, you can apply a fungicide. Long-term, ensure that your lawn is getting air by aerating it on a schedule recommended by a landscaping professional.
  • Grubs: Grubs are beetle larvae that grow underground and eat grass roots. They kill spots of grass by eating the roots in a circular pattern. The grass might look like a sponge if this is the cause. You can apply grub control products to reduce or eliminate this pest.
  • Overwatering: Too much water can kill a lawn and leave parts of it brown. Unfortunately, if you suspected fertilizer burn and added water, you may have contributed to this problem. An irrigation professional can help you make watering changes to avoid overwatering.

Avoid Brown Spots

In the future, you can avoid brown spots by applying a slow-release fertilizer. If you keep having trouble, you may want to contact a local landscaper that specializes in lawn health.