Troubleshooting Grass Failure Between Flagstones Around a Pool

The Problem

Grass between poolside flagstones in Maryland looks great in spring but rots by mid-summer. The site gets full sun; water accumulates on the impervious stone surface. Sod died, then Rebel grass seed established but rotted in center gaps. Overseeding with a rye mix gave a week of green before dying again.

Key Questions to Diagnose

• Chlorine splash: Is pool water splashing onto the grass? Chlorine kills turf.
• Drainage: Does water truly drain, or does it pond on a compacted base?
• Soil depth: Is there enough soil volume between stones for roots?
• Traffic: Is foot traffic compacting the narrow strips?

Potential Solutions

1. Improve drainage: Excavate gaps, add coarse sand/gravel base, then loose topsoil.
2. Use chlorine-tolerant grass: Seashore paspalum or certain Bermuda varieties handle salt/chlorine better.
3. Consider alternatives: Low-growing ground covers (e.g., Dymondia, creeping thyme) or permeable polymeric sand.
4. Reduce irrigation on hardscape: Adjust sprinklers to avoid wetting stones.

Without answers to the above, any replanting will likely repeat the failure. Address the root cause—drainage, chemistry, or soil volume—before reseeding.