What is Fertilizer Burn?

Fertilizer burn looks like a patch of brown grass amid green grass.

Striped, uniform lawns are a beauty to behold, as baseball fans will attest. However, if those stripes are irregular or discolored, you may have fertilizer burn. What is fertilizer burn? It’s a form of dehydration for your plants or lawn. 

We’ll explain more about what fertilizer burn is, how to prevent fertilizer burn, and how to repair your lawn or plants if fertilizer burn should happen to you.

What is fertilizer burn?

Fertilizer burn happens when high concentrations of fertilizer salts draw excess moisture from the root system of the plant or grass. This concentration of soluble salts dries out the roots, causing the plant to yellow, wilt, or die. It is a form of drought or desiccation for the plants or lawn.

Fertilizer burn is most likely to occur in these conditions:

  • Too much fertilizer is applied to the soil
  • Lack of moisture in the soil or hot weather conditions, or a combination of both
  • More likely to occur with quick-release fertilizers

What does fertilizer burn look like?

If you’ve just rolled a spreader full of quick-release fertilizer across the lawn, it should have a more lush, uniform appearance in less than a week. If you don’t have a more uniform lawn, here’s what you may see:

  • If it’s a fertilizer spill, you’ll see an irregularly shaped brown, discolored, or dead patch of lawn.
  • If it’s due to fertilizer overlap, your lawn probably looks like a checkerboard, with burned (yellow or brown) areas in the middle of each square. Or, you may have very green sections next to brown patches or lines.

If you recently fertilized the lawn and either spilled fertilizer on the grass or overlapped the rows (and your lawn looks like a checkerboard), fertilizer burn is the most likely cause.

How to prevent fertilizer burn on your lawn or plants

The causes of fertilizer burn are many, but preventing it is easy. Follow these tips to prevent fertilizer burn on your lawn:

  • Don’t apply fertilizer when your grass or plants are dormant.
  • Water before and after you apply the fertilizer.
  • Consider slow-release over quick-release fertilizer. (As long as you apply correctly, the type of fertilizer shouldn’t be an issue. If you’re worried about over-applying, go with a slow-release fertilizer.)
  • Incorporate plant fertilizer into the soil with your hand or a trowel (for ornamental or vegetable plants).
  • If it’s too hot or dry to use a granular fertilizer, use a liquid fertilizer if the lawn or plants need an extra boost.

How you apply the fertilizer is also key. Lawn Love has an entire article that explains how to fertilize your lawn step-by-step. We’ll explain what time of year, how to choose and use a spreader, how to calculate the correct amount of fertilizer, and everything in between. Check out “Fertilizer 101: Tips on How to Apply Fertilizer to Your Lawn” for a simple, clear explanation of how to apply fertilizer correctly to your lawn.

How to get rid of fertilizer burn

If you see signs of fertilizer burn, there’s good news: Fertilizer burn is easy to treat, and the affected areas may grow back. Over-fertilizing your lawn or plants is like you eating too many servings of salty french fries drenched in cheese sauce. To flush the salts out of the soil (or your body), the solution is simple: Lots of water. 

If you’ve over-fertilized, set your sprinklers to apply 1 inch of water to the area (or plant). Then, repeat once per day for three or four days, or up to one week, to ensure the salts are dissolved. If the grass or plants haven’t been killed, this should be enough water to flush out the buildup and allow the plants a chance to recover.

If the lawn doesn’t recover within a few weeks, you’ll need to reseed the areas and start fresh with new grass.

FAQ about fertilizer burn

Are there other reasons I may have brown spots on my lawn?

If you haven’t fertilized recently, here are a few other reasons you may have brown spots on your lawn:

  • Fungus
  • Scalping
  • Dormancy
  • Disease
  • Chemical or gasoline spill
  • Insects, such as grubs or chinch bugs

Can organic fertilizers cause fertilizer burn?

Yes, if you apply more than the label recommends. However, most organic fertilizers are naturally slow-release. Slow-release fertilizers, whether organic or synthetic, are much less likely to cause fertilizer burn than fast-release fertilizers if applied correctly.

Your risk of fertilizer burn should be close to zero if you apply the product according to the label’s directions. Read our next FAQ to learn more about the differences between organic and synthetic fertilizers to decide which is right for you.

What is the difference between synthetic and organic fertilizers?

Synthetic and organic fertilizer products have a few key differences:

Synthetic FertilizersOrganic Fertilizers
— Synthesized by a chemical process
— Usually more concentrated (higher N-P-K numbers on the bag), so you can use less per application
— Lower cost per pound
— Fast-release or slow-release
— Fast-release products are more likely to burn if applied incorrectly (less forgiving)
— Focus on plant health
— Don’t add organic matter to the soil
— Come from a plant or animal
— Less concentrated (lower N-P-K numbers on the bag), so you’ll use more per application
— Higher cost per pound
— Usually slow-release
— Less likely to burn (more forgiving)
— Focus on soil health
— Add organic matter to the soil

Here are a few examples of synthetic fertilizer ingredients:

  • Urea
  • Sulfur-coated urea (a slow-release formula)
  • Triple superphosphate, or superphosphate
  • Potassium nitrate

These ingredients are common in organic fertilizers:

  • Feather meal
  • Bone meal
  • Blood meal
  • Cottonseed meal
  • Kelp meal

Weigh the pros and cons of each to decide which fertilizer is appropriate for your home fertilizer program.

If your lawn fertilizer applications have been less than successful, contact a local lawn care professional. They’ll mow, edge, and fertilize so your lawn looks professionally cared for all year long. And they’ll make sure your baseball stripes come from the lawn mower, not the fertilizer.

Main Photo Credit: Sten Porse | CC BY-SA 3.0, via Wikimedia Commons

Sarah Bahr

Sarah is a writer who has previously worked in the lawn care industry. In her spare time, she likes to garden, raise chickens, and mow the grass with her battery-powered lawn mower.