It rains for weeks in the summer, the nights are swelteringly warm. Suddenly they appear: Circular, rust-red spots, huge white spore nets in the morning, or dark green fungal circles on the lawn carpet.
Almost every well-maintained lawn is struck by fungal diseases once in its life. The good news: 99 percent of these diseases can be stopped by fast, purely organic or mechanical care (so-called curative or prophylactic care), completely without highly toxic fungicides from the internet, which are mostly illegal for private home gardens anyway.
Get to know your opponents so you can react immediately and purposefully!
The 3 Most Common Fungus Opponents in the Home Garden
1. Red Thread (Laetisaria fuciformis)
Symptoms: The absolutely most typical summer phenomenon. Irregularly large, yellow to brown areas form in the lawn. If you look at the grass blades there from close up (best early in the morning when they are wet with dew), you often see pink to rust-red, slightly gelatinous fungal threads (mycelium) growing from the tips of the dried leaves. When it occurs: Mostly in late spring or summer with high humidity, warm temperatures, and "standing air". The Cause & Cure: Red Thread is the classic deficiency disease. It literally screams: "Give me nitrogen immediately!". The fungus exclusively attacks plants that are starved. Measures: An immediate, easily soluble nitrogen fertilization often makes the grass grow so fast that the sick leaf parts simply "grow out" and land in the catcher basket the next time you mow.
2. Snow Mold (Microdochium nivale)
Symptoms: Contrary to what the name suggests, this fungus does not need snow. It often occurs in the fall, mild winter phases (around freezing with drizzle), or very early spring. Flattened, brownish-grayish, often circular patches form. When there is high moisture (e.g., after snowmelt), a very fine, white to slightly pink mold fluff often lies like a spider web over the affected turf. The leaves there are stuck together. When it occurs: In wet and cold weather (32°F to just under 50°F) and highly covered conditions (lots of clippings, snow cover, or compressed fall leaves). The Cause & Cure: Too much moisture coupled with tissue that is too soft! If you work with normal summer fertilizer in the late fall, the grass drives soft leaves (succulence) that burst open at the first frost. The wound becomes the main entrance for the spores! Measures: Prevention is everything. Strictly use potassium fertilizer starting in October to seal the cell walls frost-proof (immune system). In the spring, lightly rake out (comb) the diseased lawn, mow lower to create wind circulation in the turf, and overseed promptly.
3. Fairy Rings (Marasmius oreades and others)
Symptoms: Fairy rings are creepily fascinating. They start as a small dark green ring whose diameter grows extremely year after year (it eats its way outward in a circle). There are 3 types distinguished. In extreme manifestations (Type 1), brown, dead grass curls up on the inside of the circle, the outer edge of the circle grows dark green like crazy, and partly poisonous mushrooms pop out on the ring boundary. When it occurs: Independent of the season, very often in gardens surrounded by former forest or agricultural areas or when root remains of huge trees buried in the ground rot away after building a house. The Cause & Cure: The mushroom eats this dead wood underground (partly a foot and a half deep!). The dense, white mycelium (network) of the fungus grows so strongly under the earth that it makes the lawn soil water-repellent (hydrophobic). Drops bounce off; the lawn on the ring literally burns due to water deprivation. The dead organic material then releases nitrogen locally, which makes the ring grow paradoxically dark green on the outside. Measures: Intensively aerate the complete ring (punch holes up to 8 inches deep, often with a digging fork!), fill with pure quartz sand and intensely water, often with wetting agents (a drop of dish soap in the water) so the water overcomes the barrier layer. And: Apply a lot of organic fertilizer to cultivate antagonistic bacteria that eat up the fairy ring in the soil.
The Early Warning System in Your App
Sick leaves reveal the mistakes in the soil long before they die extensively. You don't have to become a mycologist to distinguish Red Thread from drought.
AI Camera Analysis
Have you discovered white spore nets? Take a photo with the LawnCoach app. Our machine learning model analyzes the damage pattern and often tells you unerringly: "That is snow mold."
Prevention Through Timing
The app reminds you never to sprinkle the lawn in the evening – because a dew-wet night and warm summer temperatures are the number one invitation for summer diseases.