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Kentucky bluegrass · Poa pratensis

Why are there spots on my Kentucky bluegrass?

Spots on your grass blades are often signs of fungal activity like dollar spot or powdery mildew. Look closely at the shape and color of the spots to identify the culprit.

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spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Examine the shape of the spots.
  2. Check if the spots have a white powdery texture.
  3. Look for circular patterns in the turf.

Likely causes

  1. Dollar Spot

    Most likely

    How to tell: Small, bleached circular patches appear on the turf. These spots are usually about the size of a silver dollar.

    What to do: Apply a fungicide labeled for dollar spot during the early morning. Increase your nitrogen fertilization to help the grass outgrow the infection.

  2. Powdery Mildew

    Possible

    How to tell: A white, dusty fungal growth covers the surface of the leaves. This usually happens in shaded areas with poor air circulation.

    What to do: Prune back nearby trees or shrubs to increase sunlight and airflow. If the infection is severe, use a fungicide specifically for powdery mildew.

Leaf spots on other plants

Find out what's wrong with your kentucky bluegrass

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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When to worry

Take action immediately when you see circular patches, as they can expand and kill large areas of turf. Small, isolated spots are manageable with simple cultural changes.

Stopping it coming back

Water your lawn early in the morning so the blades dry out quickly during the day. Keep your mower blades sharp to prevent tearing the grass.

Kentucky bluegrass: spots? Check yours with a photo

Every plant is a little different. Take a photo of your kentucky bluegrass and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Will these spots go away on their own?
Some minor fungal issues resolve when the weather changes. However, dollar spot usually requires treatment to stop it from spreading.
Should I mow over the spotted areas?
Avoid mowing when the grass is wet to prevent spreading fungal spores. Clean your mower deck after cutting infected areas.

Guides to these causes

More problems with Kentucky bluegrass

Back to the Kentucky bluegrass guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.