Things You'll Need
Grassy weeds invade lawns and compete with the desirable grass for the soil's nutrients. Most grassy weed problems stem from gardeners fertilizing too early in the season, under-watering, and maintaining a layer of thatch that is over a half-inch thick. Thatch is the dead and living organic layer sandwiched between the soil and the grass blades. While you can kill the existing grassy weeds, it is important to correct many of the cultural problems that are causing weed growth in the yard.
Measure the depth of your thatch layer. If it is more than a half-inch thick, it will limit the success you have with an herbicide to control grassy weeds. If the thatch layer is too thick, rent a power dethatcher from a gardening supply store. Push the dethatcher back and forth across the lawn. Rake up the debris.
Examine your lawn for the invasive grassy weed. Sprinkle colored chalk around the grassy weed areas to pinpoint the spots that need your attention.
Dig up the grassy weeds with a shovel. Push the shovel 3 to 4 inches into the soil and lift, raising the grassy weeds by their roots. Transfer the weeds to a wheelbarrow and throw them away. Avoid placing them in compost, so the weed seeds aren't distributed across your lawn.
Place a piece of landscaping fabric over the bare areas. Measure the landscaping material. Cut the material with scissors. Lay the material down with bricks placed on top. Allow the landscaping material to smother weed seeds for 6 to 8 weeks during the hot summer months.
Lift up the landscaping material. Till the bare spots with a tiller. Smooth out the bare areas with the back of a rake. Broadcast seeds into the bare areas. Plant 16 seeds per square inch. Cover the seeds with one-eighth inch of compost. Water the area thoroughly.
Water grass seeds four times a day for six weeks. Spray a light mist on these areas.
Wait at least seven weeks to fertilize your grass seeds.