Hard White Growths in Fescue Lawn: Mushrooms from Buried Wood

Marble-to-baseball-sized hard white balls that release black powder are mushroom fruiting bodies (likely sclerotia or puffballs). They indicate:

• Buried wood (old tree stump, construction lumber) decomposing underground.
• Excess moisture from poor drainage or overwatering.
• Low soil pH favoring fungi over grass.

Action Plan

1. Rake daily to remove fruiting bodies before spores disperse.
2. Fix drainage—core aerate, topdress with compost.
3. Raise pH with pelletized lime (target 6.5–7.0).
4. Apply organic nitrogen (blood meal, compost, grass clippings) to strengthen grass.
5. Turn off automatic irrigation—let dew provide morning moisture.

If a tree stump is the source, mushrooms may persist for years as lignin decomposes. Consistent cultural management reduces them over time.