How to Get Rid of Powdery Mildew in Your Lawn
Powdery mildew is a common fungal disease that can affect various plants, including your lawn. If you've noticed patches of grass turning white or developing a powdery coating, you may be dealing with this pesky problem. While powdery mildew is not usually fatal to grass, it can weaken your lawn, making it more susceptible to other issues.
This guide will cover what powdery mildew is, why it appears, whether it's harmful, and, most importantly, how to get rid of it and prevent it from returning.
What Is This Powdery Mildew on Grass?
Powdery mildew is a fungal disease caused by Erysiphe graminis. It manifests as a white or grayish powdery substance on grass blades, primarily in shaded, humid areas. Unlike other fungal infections that thrive in wet conditions, powdery mildew prefers dry foliage and high humidity.
How to Identify Powdery Mildew
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White or gray powder-like growth on grass blades.
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Grass turning white or pale in affected areas.
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Reduced vigor and slower growth of infected grass.
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Symptoms usually appear in shaded areas with poor air circulation.
Why Is Powdery Mildew on Your Lawn a Problem?
Powdery mildew is more than just a cosmetic issue. It can impact your lawn's overall health by interfering with photosynthesis, reducing the grass's ability to absorb sunlight and produce energy. Over time, this weakens your lawn, making it more vulnerable to stress, drought, pests, and additional fungal infections. Untreated powdery mildew can thin out your turf, leading to patchy, unhealthy-looking grass. However, if treated early, lawns typically recover well with proper care and maintenance.
Powdery mildew can sometimes be mistaken for other lawn issues, such as drought stress, nutrient deficiencies, or other fungal infections, making accurate diagnosis essential for proper treatment.
What Causes Powdery Mildew in Lawns?
Understanding the conditions that encourage powdery mildew can help you prevent it. Here are the primary factors that contribute to its development:
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Shaded areas — Grass growing under trees, fences, or buildings is more susceptible.
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High humidity — While the fungus doesn’t need moisture on the leaves, humid conditions encourage its spread.
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Poor air circulation — Dense or overgrown turf traps humidity, providing an ideal environment for mildew.
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Nutrient deficiencies — Lawns lacking proper fertilization, especially nitrogen, are at higher risk.
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Drought stress — Stressed grass is more vulnerable to infections.
Related: Lawn Care Tips for Shaded Areas
Which Grass Types Are Most Vulnerable?
Certain grass types are more susceptible to powdery mildew than others, particularly those that struggle in shady conditions. Commonly affected grass types include:
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Kentucky Bluegrass — Highly vulnerable, especially in shaded areas.
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Fine Fescues — Moderately susceptible but more resistant than Bluegrass.
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Perennial Ryegrass — Can develop mildew in high-humidity conditions.
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Tall Fescue — Less prone to powdery mildew but can still be affected in dense, shaded areas.
Understanding your grass type can help determine the best prevention and treatment methods.
Does Powdery Mildew Affect Other Plants?
Powdery mildew can infect a wide range of plants beyond grass, including flowers, vegetables, shrubs, and trees. However, different species of powdery mildew fungi are host-specific, meaning the strain that affects your lawn is not the same one that infects roses or cucumbers, for example. So, lawn powdery mildew won’t spread to your vegetables, but they can develop their own version of the disease.
While symptoms such as white, powdery fungal growth are similar across different plants, treatment and prevention methods may vary depending on the species affected, so make sure you check the label on your fungicides. Those suitable for use on vegetables may not be safe for grass, and vice versa.
How to Fix Powdery Mildew on Grass
If you notice powdery mildew on your lawn, don’t panic. There are several effective powdery mildew treatments to restore your turf’s health.
1. Improve Sunlight Exposure
Since powdery mildew thrives in shaded areas, increasing sunlight exposure can help prevent and reduce outbreaks:
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Trim trees and shrubs to allow more light to reach the grass.
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Consider overseeding with a shade-tolerant grass variety if shade is unavoidable.
2. Increase Air Circulation
Better airflow discourages mildew growth:
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Mow at the proper height to prevent overly dense grass.
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Aerate compacted soil to improve air circulation around the roots.
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Space out plants or landscape elements that may be restricting airflow.
3. Water Properly
Watering habits play a significant role in preventing powdery mildew:
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Water deeply but infrequently to encourage strong root growth.
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Water early in the morning so excess moisture can evaporate throughout the day.
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Avoid overhead watering in shaded areas.
4. Fertilize Correctly
Under-fertilized lawns are more prone to fungal diseases. A balanced fertilization plan can help combat powdery mildew:
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Look for fertilizers with N-P-K numbers like 14-7-14, which provide balanced nitrogen, phosphorus, and potassium for resilient turf. If your grass is already battling a fungal disease, try a fertilizer with high potassium, with numbers like 12-0-24 or 7-0-20. Potassium strengthens cell walls, improving disease resistance and overall lawn durability.
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Avoid excessive nitrogen, which can promote soft, lush growth susceptible to mildew.
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Use slow-release fertilizers for a steady nutrient supply.
Recommended Fertilizers
To strengthen your lawn and reduce the risk of powdery mildew, consider these fertilizers from Golf Course Lawn Store:
Lebanon Complete 14-7-14 Fertilizer
Country Club Complete 14-7-14 is a premium fertilizer designed to enhance your lawn’s health and appearance. With essential micronutrients like iron, magnesium, and manganese, it promotes vibrant, deep green grass. The addition of sea kelp and humic acid supports soil health, while the 14-7-14 formula offers a balanced mix of nutrients for a lush lawn. Ideal for warm and cool season grasses, it delivers a rapid green-up in just 5-7 days and covers up to 11,400 square feet per 40lb bag.
This fertilizer blends fast-release nitrogen with Meth-Ex slow-release nitrogen for quick results without excessive growth. It also contains 7% phosphorus to support deep root development. The 100% SOP potassium in the blend provides non-burning, immediately available nutrients, along with plant-friendly sulfur.
Lebanon Stress 12-0-24 Fertilizer
Country Club Stress 12-0-24 is a premium fertilizer designed to help your lawn thrive during summer heat and winter cold. Its high potassium content and a blend of nitrogen and micronutrients ensure rapid green-up without overgrowth, making it perfect for a resilient, vibrant lawn.
The high potassium helps your grass withstand seasonal stress, while 12% nitrogen delivers a quick green-up in 5-7 days. Iron, magnesium, and manganese provide a deeper green color, and the formula is designed for easy absorption, covering up to 10,000 square feet per 40 lb. bag.
Stress 12-0-24 combines fast-release and Meth-Ex slow-release nitrogen for steady growth, while 24% of the blend is 100% SOP potassium, which is non-burning and immediately available to your grass. It also includes sulfur, iron, and other micronutrients to boost plant health and stress resistance.
5. Use a Powdery Mildew Fungicide
If cultural practices alone don’t control the mildew, applying a powdery mildew fungicide may be necessary:
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Look for fungicides containing propiconazole, azoxystrobin, or myclobutanil.
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Apply according to label instructions, ensuring even coverage.
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Consider using organic treatments like neem oil or sulfur-based products for a natural approach.
Recommended Fungicides
For the best powdery mildew treatment, we recommend:
Pillar SC Intrinsic® Brand Liquid Fungicide
Pillar SC Intrinsic® Brand uses two active ingredients — triticonazole and pyraclostrobin — to provide fast-acting, long-lasting disease control for up to 28 days. Unlike other fungicides, it has a uniform application rate of 1 oz per 1,000 sq. ft., no matter what fungal disease you are fighting, making it easy to use.
It controls a wide range of diseases, including powdery mildew, brown patch, dollar spot, anthracnose, fusarium patch, and pink snow mold, improving your lawn’s overall health and stress tolerance.
Pillar SC Intrinsic® Brand is suitable for cool- and warm-season grasses, including Kentucky bluegrass, Bermuda, Zoysia, and more. Apply as early as April or May using a battery-powered 4-gallon sprayer with a large droplet nozzle, and water in after application for best results.
The liquid formula works quickly to combat disease and promotes healthier, more resilient grass.
Headway G Granular Fungicide
Headway G is a broad-spectrum granular fungicide that effectively controls common lawn diseases with just one application. It delivers powerful disease prevention and eradication by combining two active ingredients, azoxystrobin and propiconazole, to target a wide range of lawn fungi.
This product stops the spread of diseases like brown patch, dollar spot, and fairy ring, ensuring your lawn stays healthy and vibrant. Safe for all grass types, it covers up to 15,000 square feet with a single 30 lb bag.
Headway G's combination of fungicides provides dual modes of action, allowing for broader coverage and increased effectiveness. It’s ideal for preventative and curative treatments, saving you time and money compared to using multiple products.
To prevent lawn diseases, apply in spring and fall for optimal results. The product is easy to apply with a broadcast spreader and is safe for pets and people when used as directed.
Headway G is suitable for cool-season lawns like Kentucky Bluegrass and Fescue, as well as warm-season grasses like Bermuda and Zoysia. Apply to a dry lawn and water in within 48 hours.
6. Natural Remedies
In addition to chemical treatments, natural remedies can be effective against powdery mildew:
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Milk spray: To combat powdery mildew, a solution of 40% milk and 60% water can be applied to affected areas.
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Baking soda spray: Add one tablespoon of baking soda and a teaspoon of liquid soap into a gallon of water and apply to the lawn.
These natural treatments can be applied as needed to manage low-level powdery mildew outbreaks.
Related: How to Get Rid of Fairy Ring Disease in Your Lawn
How to Stop Powdery Mildew from Coming Back
Preventing future outbreaks is just as important as treating the current infection. Here’s how you can stop powdery mildew from returning:
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Choose resistant grass varieties —Some grass types are less susceptible to mildew. Warm-season grasses are generally more resistant but may not be right for your climate. Bahia grass is one of the hardiest and disease-resistant varieties. Of the cool-season grasses, Tall Fescue has better disease resistance.
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Improve soil health — Regular soil testing and amendments ensure optimal growing conditions.
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Maintain proper lawn care practices — Regular mowing, aeration, and fertilization keep the grass strong.
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Reduce shade and improve drainage — More sunlight and better airflow create an inhospitable environment for mildew.
Related: Identifying Grass Types
Dust Off Powdery Mildew — Bring Your Lawn Back to Life!
Powdery mildew may be a stubborn lawn issue, but with the right care and treatment, you can restore your grass to its lush, green state. By improving sunlight exposure, adjusting watering habits, and using high-quality fungicides like Pillar SC Intrinsic® Brand and Headway G, you can stop powdery mildew in its tracks. With consistent lawn care, your grass will remain lush, green, and mildew-free throughout the growing season.
Don’t wait for the problem to spread — shop our premium fungicides and lawn care products at Golf Course Lawn Store today and take control of your lawn’s health!
Ron Henry
Ron Henry is the founder of Golf Course Lawn, which is dedicated to helping homeowners achieve golf course-quality lawns. He holds a certificate in Sports Turfgrass Management from the University of Georgia. With expert knowledge in turf care, fertilization, and weed control, he shares practical tips and product recommendations to create lush, healthy lawns.