How to eliminate mold on your lawn

Look for unusual white, yellow, or brown patches. These may appear as shapeless streaks or round spots. Often, you can even see the soil beneath the distressed grass. Mold patches usually continue to spread outwards.

Look for gray, black, orange, red, or purple spots on the grass blades or stems. These could be signs of leaf spot disease, a fungal infection that spreads from the leaves down to the roots, causing the grass roots to rot, eventually leading to grass death. The fungal infection will continue to spread if left untreated.

Observe any gray, black, pink powdery substance or a layer of fibers covering the grass blades. This indicates red leaf disease, pink mold, or white mold. Red leaf disease and pink mold often appear together and spread easily. White mold can also spread but is less likely to penetrate into the soil.

Pay attention to grass that turns dark, wet, and slimy. This could be a sign of slime mold, which is very common in humid environments. If you spot slime mold on your lawn, you’ll also notice white fungal growth resembling cotton fluff around the affected area.

Avoid spreading mold to other parts of the lawn. Fungal diseases are highly contagious, so foot traffic, lawn mowers, or wheelbarrows can easily spread the mold to healthy patches of grass. If you must walk on the grass, cover your shoes with plastic and remove them before stepping on clean areas.

• Be sure to collect and dispose of grass clippings after mowing.

Apply fungicide to your lawn. Choose a fungicide that targets the specific mold infecting your grass. There are two types of fungicides: contact and systemic. Contact fungicides are liquid-based and coat the plant surface, killing the fungal spores that come into contact with it. However, these tend to lose effectiveness quickly. Systemic fungicides are typically granular and dissolve into the soil, penetrating the root system for longer-lasting treatment. Always follow the product instructions on the packaging.

• Benomyl is effective in treating a variety of molds, including snow mold, brown patches, and dollar spot.
• Triadimefon works well for treating anthracnose and rust disease.
• Chlorothalonil is most effective in treating brown patch and red leaf disease.
• Currently, there is no complete cure for the mold once it has infected your lawn, and fungicides will only treat necrotic spots if you also remove the thatch from the grass.

Try natural mold control methods. If you prefer to avoid chemicals, you can opt for natural mold treatments. Neem oil, compost tea, and baking soda solutions all have mold-fighting properties. You can apply these natural remedies to the affected areas by pouring or spraying them on the moldy spots.

• Natural remedies are most effective when the mold is still in its early stages or only in small quantities.
• Avoid allowing people and pets to come near the treated areas for a few days afterward.

Note that some fungal diseases are seasonal. Certain fungal diseases are triggered by weather conditions. Gray snow mold typically dies off when temperatures rise above 4°C. Warm weather can immediately eliminate mold. Similarly, some fungal species will disappear when the sun warms and dries out the lawn. Other molds, such as powdery mildew, thrive in dry, high-humidity conditions.

• Fungal diseases may resolve on their own if you properly maintain your lawn.

Only water the grass when necessary. Most lawns require about 2.5 cm of water per week, but homeowners often water more than needed. Many mold species thrive in moist conditions, so overwatering can encourage mold growth.

• However, don’t let the grass get too dry either. Dry soil weakens the grass and makes it more susceptible to diseases.
• The best time to water your lawn is in the morning, allowing the soil to absorb the required amount of water and excess moisture to evaporate throughout the day.
• If you use a sprinkler system, check to make sure the sprinkler heads are working properly. You should also calculate how much water your lawn is receiving to make any necessary adjustments.

Use slow-release fertilizers with low nitrogen content. Fungal diseases can occur if you apply too little or too much fertilizer. To maintain a healthy balance, opt for a slow-release organic fertilizer that contains potassium and nitrogen. This will promote healthy grass growth and help prevent fungal infections.

• Avoid over-fertilizing with nitrogen, as this can cause the grass to grow too quickly and weakly, making it more susceptible to mold infections.
• Always follow the product instructions on the packaging to avoid improper application.

Remove fallen leaves in your yard during winter. Gray snow mold can grow under fallen leaves on your lawn. To prevent mold from developing, rake up and remove the leaves before the snow falls.

Set your lawn mower to its highest setting. When mowing, only cut about half the height of the grass. Instead of cutting the grass too short, let it grow thick and lush. Newly grown grass tends to be weaker and more prone to fungal infections. While it may require more effort, your lawn will be healthier if it’s not cut too short.

• Keep your mower blades clean and sharp.
• Cut the grass slightly shorter before snowfall to prevent snow mold.

Rake up dead plant material from your lawn. This thatch layer often consists of grass clippings, leaves, plant roots, and branches that cover the soil. The soil needs to be well-aerated to prevent fungal infections, so cleaning up the thatch can help prevent mold problems.

• It’s best to use a gas-powered dethatcher for this job, which you can rent from garden tool rental shops.
• The dethatching process is usually done in the spring.

Till the soil annually to loosen it up. Tilling helps aerate the soil, preventing it from becoming compacted. This step is crucial and should be done at least once a year to ensure water, fertilizers, and treatments can penetrate the soil. Otherwise, grass roots may not absorb enough nutrients or treatments.

• You can rent a tiller to aerate the soil.

Apply a layer of mulch after tilling the soil annually. Mulch is a layer of organic, well-draining material that improves soil quality. Common mulch materials include coarse sand, humus, peat moss, or compost. The mulch helps grass grow stronger, enhances drainage, and prevents excess moisture. Spread the mulch across the lawn and rake it evenly.

• Before applying mulch, make sure to clear away the thatch and loosen the soil.

• Choose a grass type suitable for your climate and soil. Native grasses are more resistant to local fungal spores, while many non-native varieties are weaker against them.
• Brown patches on the lawn may not always be fungal mold. These spots can result from other factors like drought, poor soil quality, insect infestations, or damage caused by animals.

• Be cautious when using chemical fungicides, as these chemicals can be harmful. For the best results, allow the treated area to remain isolated for several days after application.
• Avoid letting people or pets come near the lawn during or after fungicide application.
• Always use fungicides carefully and as directed on the product packaging.