rsz johnson farms 2015 1 scaled 1

Why Is My Grass Turning Yellow? (This is Why Your Grass is Not Green)

Photo of author

Written By: Mark Marino

a Massachusetts Core Applicator License holder and owner/operator of Lawn Phix,

Updated on

1 comment

No AI pledge. Authored and reviewed by Mark, not robots. Learn more.

If you buy something from one of our affiliate links, we may earn a small commission at no extra cost to you. I've used these products and provided an honest opinion on every product I review. This helps support our site and its free content, lawn care guides, and calendars. Learn more.

Why Is My Grass Turning Yellow?

Heat stress, fungal diseases, pest infestation, and even dog urine can all conspire to turn your lush green lawn a different color. Yellowing grass is typically associated with a lack of nitrogen or iron. Yellow spots can even indicate that an herbicide has burned the grass leaf blades. If you notice that your healthy lawn has become brown grass, it may be suffering from a pest infestation like chinch bugs or drought stress. Yellowing leaves, whether it’s Bermuda grass, St. Augustine grass, Kentucky Bluegrass, or other grass varieties, you’ll definitely want to find out why your grass is turning yellow so you can provide the necessary treatment to keep your grass green again.

Yellowing Grass Blades

If your lawn turns yellow, it may be due to nitrogen or iron deficiencies. Although a lawn fungus could cause yellow grass spots depending on the grass type in question, it’s most likely a nutrient deficiency or dog urine. The main causes of yellowing grass are:

Iron Deficiency (Iron Chlorosis)

Entire lawn turning yellow? It’s likely because you need to feed your lawn with an iron fertilizer. But how do you know if it’s an iron deficiency or if your lawn lacks other nutrients? An iron deficient yellow lawn will typically begin to yellow at the top of grass blades. If you notice that the top grass blades are yellowing first, you should suspect iron deficiency as the root cause of your yellow grass.

Lack of Nitrogen

Lack of nitrogen can also cause your St. Augustine grass or Bermuda grass lawn to turn yellow. Nitrogen is a core nutrient that grass needs. Lawns turn yellow without adequate nitrogen. Lawn food, or fertilizer, can provide your grass with the nitrogen it needs to thrive. Remember that one way to determine if your grass has a nitrogen deficiency is to check the bottom of your grass blades. Nitrogen deficiencies will turn the bottom of the grass yellow first. You can conduct a soil test to determine if your grass needs nitrogen.

Over Watering

Over watering can lead to yellow grass too. Too much watering can wash away essential nutrients like nitrogen from the soil. Also, too much water can cause the grass to grow shallow roots. Shallow roots have difficulty accessing enough oxygen and nutrients to keep the lawn green and healthy. Remember, too, that excess water leaves your cool season grass or warm season grass more vulnerable to fungal diseases. 

Excess Fertilizer

Did you know that too much fertilizer can make grass turn yellow? Fertilizer burn will cause yellowing at the base of grass blades and browning at the top of the grass. Avoid excess nitrogen salts and use a slow release fertilizer instead. Fertilizer burn, also known as leaf scorch, can also slow down new grass growth. Prevent grass turning yellow by slowing down the amount of fertilizer you provide your grass.

Dog Urine

If you have a dog or dogs walk by your grass, your lawn’s yellow spots could be caused by dog urine. Dog urine won’t make all grass yellow, but it will develop unsightly yellow spots. Dog urine contains a lot of nitrogen; the excess nitrogen in dog urine can lead to yellow spots throughout your grass or wherever your dog pees.

How to Make Grass Green Again

You can repair yellow grass and make your grass green again by first determining what has caused yellow spots or yellow grass. This way, you can treat the root cause of your grass turning yellow. Here are some tips to make your grass green again:

  • Water your lawn deeply in the morning. Avoid watering grass in the evening to reduce the risk of lawn diseases. Watering grass deeply ensures that water penetrates the soil surface to encourage strong and deep grass roots. You may also have to adjust your irrigation system to reduce water delivery.
  • Apply dog urine neutralizer to dog urine spots quickly. Seed urine spots to replace dead grass. You may need to add new sod to dead grass spots caused by dog urine.
  • If your grass shows signs of turning yellow because of excess fertilizer, apply it less often. Conduct a soil test to make sure it needs lawn food. 
  • Quickly treat lawn diseases to prevent a yellow lawn or brown grass. Lawn diseases can also cause your grass to turn white or gray.

Why Is My Grass Turning Yellow FAQs

Can yellow grass become green again?

Yes, turning yellow grass back to green grass is often possible. Although, in some cases, you may have to replace grass with new sod or plant new grass seed. For instance, dog urine spots may not turn green again if dog urine neutralizer is not applied soon enough.

Why is my grass suddenly turning yellow?

Yellow grass may be caused by excess fertilizer. If you recently fed your lawn too much nitrogen fertilizer, it may quickly turn yellow.

What does yellowing grass indicate?

Yellowing grass most likely indicates a lack of nutrients, particularly nitrogen (N) and iron (Fe). This can generally be fixed with a balanced lawn fertilizer as long as the grass roots are still healthy and not damaged. Yellow grass can also be burned from a weed killer or other herbicides or overwatering.

How do you fix a yellow lawn?

Depending on what the root cause is, you can fix yellow grass by applying nitrogen fertilizer and iron supplements to your lawn for healthy grass.

Can grass recover after turning yellow?

Yes, grass can usually recover after turning yellow. The most common indicators for yellow grass are lack of nitrogen, iron deficiency, overwatering, or herbicide burn.

How do I get my grass green again?

To get green grass again, make sure you are regularly feeding your lawn with fertilizer and the nutrients it needs. Nitrogen and iron can usually make grass green again quickly. Maintain proper watering and mowing practices to maintain a green lawn.

  • YELLOW GRASS: lack of Nitrogen and/or Iron, and can also indicate herbicide burn
  • BROWN GRASS: Wide range, indicating lack of water, drought stress, dormancy, and signs of insect and grubs
  • ORANGE GRASS: indicates fertilizer burn, specifically from excess Nitrogen
  • WHITE GRASS: indicates lawn disease or fungus, particularly powdery mildew
  • GRAY GRASS: also indicates lawn disease or fungus or disease stress
    • GRAYISH HAZY GRASS: indicates a stressed lawn due to mower height.  Cutting the lawn too short causes this hazy discoloring
  • RED GRASS: indicates red thread or pink patch
  • BLACK GRASS: indicates excessive Iron (Fe) or black lawn fungus (Cladosporium)
  • BLUE GRASS: or purple grass, indicate heat and drought stress

Was the information on this page helpful?

Thanks for your feedback!
Author's Note: this piece has been updated for accuracy since its first publication on
Photo of author
Author: Mark Marino
My name is Mark Marino, and I am the founder, owner, and operator of Lawn Phix. With a passion for lawn care and turf nutrition for over a decade, I've dedicated countless hours to correcting soil and perfecting lawns. Today, my expertise, backed by formal courses at UMass Extension Pesticide Education, allows me to offer top-tier lawn care services and advice. I am a fully licensed and insured lawn care applicator in Massachusetts, specializing in comprehensive turf nutrition, weed control, and lawn pest control. My license number is AL-0053865. Contact me at [email protected] or +1 (508) 500-8402.

1 thought on “Why Is My Grass Turning Yellow? (This is Why Your Grass is Not Green)”

Leave a Comment