Roundup on Dormant Grass

Dormant Grass

• Grass goes dormant during the cold, winter months. Some grass types, such as cool-season grass, spread slowly if the temperatures are moderate. Stunted growth and brown discoloration are signs grass has gone dormant. Its difficult for gardeners to know if their grass has gone completely dormant, because grass roots continue to grow until temperatures dip below 55 degrees, according to Cornell University. Brown, dormant-looking grass may still be growing, which means it suffers from herbicide damage.

Bermudagrass

• Bermudagrass is the only type of grass that can be sprayed with Roundup when it has gone dormant, according to gardening Reeves. Warm-season grass types, such as zoysia, St. Augustine and centipede, do not go completely dormant in winter. Spraying these grass types with Roundup lead to bare areas in the spring. To know if Bermudagrass is dormant, examine the grass carefully for any green vegetation.

Spraying Bermudagrass

• Choose a dry and wind-free day for spraying weeds growing in your Bermudagrass lawn. Roundup needs 24 hours of dry weather to absorb into the weeds' foliage. Spread plastic over any surrounding seedlings or ornamental plants to protect them from the spray. Focus the spray on the weeds' foliage. Reapply the Roundup again in a few days. Plan to reseed dense, weed-populated areas in the spring with Bermudagrass.

Removing Weeds in Other Lawn Types

• Gardeners can remove weeds using Roundup in other lawn types, as long as they are careful. Spray a rag with Roundup. Wrap the saturated rag around the end of a rake. Paint the herbicide on your weeds growing above your dormant grass with the rag. Try to make contact with the foliage as much as possible.