Grass blades move water through their lengths for nourishment, but this moisture freezes inside the turf when you observe a light frost across the outside surface. When the grass’s internal water freezes, the cells expand and rupture. When grass is frozen, any damage to the grass at this stage is like stabbing it with an “ice dagger.” Stepping on frozen grass causes the ice to penetrate even more deeply, damaging it more than it may have been before.
Grass can withstand some damage above ground level, and as long as the freeze is not too severe the roots get a chance to heal the damage as grass warms and grows. After several nights of light frost or after a heavy frost, the plant is more damaged and will take longer to recover.