Black Fungus on Newly Seeded Lawn: Identification & Organic Treatment Options

Mysterious Black Substance on New Grass After Tree Removal

After tree and driveway removal, a homeowner added black dirt, seeded, mulched with straw, and watered diligently. Two days ago, a liquid resembling crude oil appeared and is expanding. Fear of losing the entire new lawn.

Diagnosis: Fungal Infection

The expert (Charlotte) identifies this as a fungus, possibly the "black mold" she's seen in other queries. Two organic treatments:

1. Baking soda spray: ¼ cup per gallon water, saturate affected area
2. Corn gluten meal: Apply and water in (also acts as fungicide)

Alternative: Dilute Bleach (Use Caution)

If it's the notorious black mold, 1–2 tablespoons bleach per gallon water may work (Charlotte used strong bleach on a wall). Test small area first. Avoid breathing fumes; consult doctor if concerned.

Geographic Pattern?

Charlotte wonders if these cases cluster regionally. Prompt treatment is essential to save the new seeding.

Note: This answer was also copied to another user (Georgia) with identical symptoms.