Black Mold on Newly Seeded Lawn: Adjusting Irrigation to Eliminate Fungus

Diagnosis: Overwatering Causes Mold

Watering three times daily (1 AM, 6 AM, 6 PM) keeps the surface constantly wet—ideal for black mold (likely slime mold or fungal growth). This schedule is only for germination; once grass sprouts (around 7 weeks), it must change.

Transition to Deep, Infrequent Watering

1. Weeks 1–2: Reduce to twice daily, increasing run time.
2. Weeks 3–4: Once daily, longer duration.
3. Week 5 onward: Once per week, 1 hour (or enough to wet soil 6–8 inches deep).

Let the surface dry between cycles—this kills mold and encourages deep roots.

If Seed Hasn't Germinated

After 7 weeks with mold, ungerminated seed is likely dead. Allow soil to dry completely, then re-seed with proper watering schedule.

Soil Quality Note

"Junk soil" still grows grass if drainage and organic matter improve. Focus on watering correctly first.