Frost typically occurs overnight when warm air rises and cool air near the ground drops below 32 degrees Fahrenheit. During a light frost the ground does not freeze, making it easier for grass and plants to survive.

Grass blades move water throughout the length of the plant for nourishment, but when a frost comes, the moisture freezes inside (This is what causes the frosty look of the grass). When the water freezes it expands, rupturing plant cell walls. A light frost that does not freeze the ground won’t cause severe damage because the grass roots below the soil remain above freezing point. This may result in some blade damage but the roots often have the chance to heal the damage as the grass continues to grow.

Visible Damage: After several nights or a light frost, visible damage can be seen during the days. This visible damage looks different depending on your grass type, for example, Bermuda grass can become brown and patchy and will die quickly if warmer temperatures do not return, while St. Augustine becomes yellow, brown and even sometimes purple in hue in frost damaged areas.

Impact Damage: When your lawn has frost covering it, it is susceptible to impact damage. This damage can be caused by walking, driving or leaving heavy objects on your lawn. When impact pressure is applied to a frosted lawn, the expanded water molecules slice through the plant, causing cell damage. You can often determine quickly if your lawn has impact damage because the grass will appear to look white or beige from being crushed.

• Apply 1 inch (1 hour) of water in the morning to a frostbitten lawn because hydration plummets due to the dew evaporation off the leaves.
• Reseed damaged areas once spring arrives.
• Mow only after your lawn begins to grow again and not looking discolored. Move the mower blades up .5 inches, allowing longer leaves to help shelter grass crowns from future frosts.
• Wait to fertilize for up to a month after damage, extra nitrogen from frost dehydration can cause more damage.