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What Causes Grass to Turn Yellow?

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You have finally managed to grow a luscious sheet of grass in your lawn by using the perfect seed and killing the weed with the perfect herbicide. You have diligently watered the grass and yet the grass you have grown has started growing shade of yellow. 

What causes grass to turn yellow? There might be a multitude of reasons due to which the grass is turning yellow. The grass might be affected by a bacterium or a fungus.

The grass can also have Nutritional deficiency due to changing colors. There might be some other reasons and we will be describing them in this article.

What Causes Grass to Turn Yellow?

There are a number of reasons due to which grass turns yellow on the lawn. The reasons are natural as well as man-made. The treatment of the grass changes according to the reason that causes the resulting discoloration. Let us take a closer look at the different reasons that cause yellowing of the grass:

  • Pests and Diseases are the two main reasons behind the discoloration of grass from yellow to green. There might be contamination due to bugs or bug eggs.
    • Your pets might have excreted on the ground leading to any form of bacterial or fungal infection which potentially causes discoloration.
    • If you have understood that the infection is causing the discoloration, but are unable to identify the exact reason behind this, then you can take a sample from your lawn grass to a nearby agricultural center.
    • There are professionals there who can help you to identify both the reason and the pesticide that can be used to remove the infestation.
    • A pesticide with low poison concentration built for the type of bug that has infected your lawn is easy to identify and can be used without any problem.
  • Dog Urine is a major reason behind the discoloration. Dog excreta can also cause discoloration.
    • Both dog excreta and urine have a certain component which can lead to the evaporation of the excess nitrogen present in the soil.
    • This process, however, burns the grass growing in the soil. This leads to large scale discoloration. There is no practical remedy for this problem.
    • You will need to train your dog to relieve himself in a certain spot only. You can also take your dog to do its business somewhere away from any form of grass growth.
  • Under-fertilizing is also another big reason behind discoloration. Under-fertilization usually leads to a nutrient deficiency which causes certain pockets of the grass to experience discoloration.
    • In the case of a nitrogen deficiency, there are huge patches of yellow all around the lawn. In the case of an iron deficiency, there are small patches of yellow all around the lawn.
    • We would like to recommend an iron sulfate spray or chelated iron in case of iron deficiency in the lawn.
    • If there is a nitrogen deficiency, any nitrogen-iron based product will be able to solve the problem.
  • Another major reason that can cause yellow patches in the grass is over-fertilization.
    • Over-fertilization can be caused if too much fertilizer is spread at single spraying or if there is a regular sprinkling of fertilizer more than required.
    • This can cause the pH of the grass to become higher than the required. This can lead to chemical burns in the grass and result in decolorization of the grass.
    • The only way to stop this is to stop the fertilizing process until all the grass grows to be green and healthy.

Other Ways to Change Yellow Grass to Green Grass

In case the grass in your lawn still has a number of yellow spots, you can try one of the given tricks:

  • If the yellow patch persists due to chemical burns, then you will need to remove the entire patch and replant healthy seeds. Then wait for the same to grow and cover the patch.
  • If your pets insist on urinating or defecating in a particular spot, you can water the residue and wash off the remains from the soil to remove the nitrogen-burning chemicals.
  • Warm-season grasses tend to turn yellow when the environment temperature drops. To avoid this, mix warm-season and cool-season seeds together before planting. This tends to balance the grass growth and prevents the yellow patches.
  • You can also try mowing the lawn using a mulching mower and leave the clippings of the grass in the lawn to add nutritional benefits to the grass and preventing the yellow patches.
    • While mowing, you must also ensure that the grass is not cut too short as that might also lead to nitrogen deficiency.
  • Uneven irrigation can also cause the grass to lose moisture and turn yellow. Hence, make it a point to water the grass in case of low rainfall. Visit the local agricultural center in case of any form of doubt.

Reference Link

You can use the following YouTube videos in order to know more about this subject:


We hope that this article was helpful and you were able to be aware about at least one reason due to which the grass in your lawn is turning yellow from green.

We hope that you have registered the different ways in which you can help the yellow patches from emerging in your lawn.​

Do remember that the type of grass seed planted also makes a difference along with the type of soil in your lawn. You can bring in a lawn expert to know about the different intricacies behind maintaining a flawless lawn.

They can help you to choose the correct type of pesticide which will not only remove the weeds, but also keep the nutritional balance of the soil untouched.

A watering system and schedule can also be maintained to prevent over-irrigation or under-irrigation of the soil.​

We would recommend a full lawn analysis to also know about the type of bacteria and fungus already present in the soil. So, what are you waiting for? Get into your gardening clothes and go exploring!