how to reverse over fertilization

How to Reverse Your Over Fertilized Lawn in 5 Basic Steps

In Lawn & Garden by Jamie

You just fertilized your lawn and the next day, your grass looks like someone took a lighter to it. You’ve got fertilizer burn, my friend. But don’t despair. If you take quick action, you’ve got an excellent shot of saving your lawn.

How Do You Know You Over Fertilized Your Lawn?

You’ll know if you over fertilized your lawn if you find one or more of the following:

  • Grass with brown tips that look as if they were burnt.
  • Stripes or patches of brown, green, and yellow grass.
  • Straw-colored patches.
  • Grass that’s brown and crunchy that comes out of the ground without resistance.
  • Roots that are black or have the consistency of mush.
  • The signs develop over hours or days after fertilization.

But as over-fertilization isn’t the only cause of yellow or brown grass, take a moment to rule out a few other causes.

Is the soil often dry or dotted with puddles?

Too little or too much water can cause brown spots.

Puddles that remain for more than a day can kill grass roots, causing brown spots.

Likewise, too little water can also cause grass to go dormant or to die. If you have a sprinkler irrigation system, check to see that all the sprinklers work correctly. A broken spout can leave a patch of grass dry.

Is your grass dormant?

For cool-season grass, dormancy happens during the summer or during a heatwave when the lawn receives little to no water. For warm-season grass, dormancy happens during the winter.

If your grass is dormant, the whole lawn will turn brown, but when you pull at the grass leaves, the grass will resist. Roots will look pale and healthy.

Have you used herbicides recently?

If the brown spots happen just around where you applied herbicide, or the grass has white tips, then you may have herbicide burn.

Even herbicides that are cleared for use with your grass species will harm the grass, especially if there are other stressors or when applied in too big of a dose. It’s best to hand weed when possible.

Have insects or disease overtaken your lawn?

Disease and insect damage can also cause brown spots to appear.

  • Silver dollar or loonie size brown spots that become bigger indicate Dollar Spot Disease, although Dollar Spot thrives in lawns with poor nutrition.
  • Small brown spots on leaves and stems in early spring indicate Leaf Spot. Leaf Spot prefers lawns with too much nitrogen, especially lawns stressed by drought, heat, and humidity.
  • Grass that wilts or appears to be going through a drought while being regularly watered indicates root feeding insects.
  • Grass leaves with bites indicate blade feeders, like sod webworms and chinch bugs.

What Is Fertilizer Burn?

Fertilizer burn is when grass develops burnt tips and brown spots after too much synthetic fertilizer is applied.

Synthetic fertilizer is made up of mineral salts like ammonium nitrate and high concentrations of nitrogen, especially in fertilizers marketed specifically for lawns. High amounts of nitrogen turn your grass greener (and also makes it grow faster). Applying too much nitrogen means that your lawn can’t absorb enough other nutrients, and so begins to die.

To avoid fertilizer burn in the first place, check out our article: What happens if grass gets too much nitrogen?

While fertilizer burn is pretty serious, your lawn may recover, especially if you act quickly.

But once your grass turns crunchy and the roots are black and mushy, it’s too late to save it. Your lawn is gone, although you should still do all the steps to reverse over-fertilizing before you reseed or resod. Otherwise, the remnant fertilizer will kill your next lawn before it even establishes.

5 Steps to Reverse Your Over Fertilized Lawn

Step 1 – Remove any visible granular fertilizer

If you can still see granular fertilizer, try to remove it with a wet or dry vacuum. The more fertilizer you can remove before it absorbs into the soil, the better.

Wear appropriate footwear and cover any skin exposed to the fertilizer. Synthetic fertilizers are caustic and will burn you.

Step 2 – Water lawn with 1 inch of water

It may be tempting to give your lawn a deep watering to try to get rid of the excess fertilizer all at once, but the synthetic nitrogen will end up leeching into local groundwater, which can cause huge health and environmental problems.

By giving your lawn a shallow watering several times, you’ll sink the fertilizer salts deeper into the soil where they won’t cause any problem.

A shallow watering will also avoid further stressing your lawn out, which will help it recover faster.

Step 3 – Repeat watering every day for a week

Keep up the shallow waterings every day for a week. After a few days, you may see some improvement.

Water in the mornings to avoid adding fungus to your list of problems.

Step 4 – Observe the lawn

After you’ve watered the lawn for a week, now it’s time to observe and wait. Your lawn may have already bounced back and is growing again. Or your grass may still have brown patches or yellow stripes. In that case, keep watching your lawn and watering regularly.

Burnt grass tips won’t heal, so look for fresh growth.

If your grass turns brown and crunchy, it pulls out of the ground with no resistance, and the roots are black and mushy, it’s time to plan a new lawn.

Step 5 – Mow the lawn after a few weeks

Mowing is stressful for a lawn, and 100 times more when a lawn is already sickly. So wait until your grass has been growing vigorously before you mow again. To further reduce the stress, only mow down 1 inch at a time and let the grass stay at 3 inches.

If your grass had burnt tips, this first mowing will remove most of that damage, and your lawn will look back to normal.

Final Thoughts

While your lawn can recover from anything but severe fertilizer burn, it’s best to avoid it in the first place! I always recommend switching over to organic lawn care, which not only avoids fertilizer burn but encourages a healthier lawn with less work.