How to Plant Grass on Lawn With Weeds

Purchase a granule herbicide to kill the weeds in your lawn. Selective herbicides are formulated to kill certain vegetation, and leave other types alone. Read the package information on the herbicide before purchasing it. Some products, even the selective varieties, may damage certain types of grass.

Fill a garden spreader with a selective granule herbicide. Wait for a warm day with no possibility of rain for at least two days. According to the University of Minnesota Extension Service, a post-emergent selective herbicide is best applied when temperatures are between 60 and 80 degrees. Read the directions on the label to determine how much herbicide you need for your size lawn. Put half of the required quantity into the spreader.

Push the spreader back and forth over the lawn to cast the granules. Fill the spreader with the other half of the herbicide and repeat in the opposite direction. You ensure full coverage by crisscrossing the yard with the herbicide. After applying the herbicide, wait at least one week for the weeds to die. If the yard still has weeds after time is up, repeat the process.

Rake the lawn vigorously with a stiff pronged rake to remove dead weeds and any buildup of dead grass roots. While you perform the raking process, commonly referred to as dethatching, you create ridges in the soil, which gives the seeds a place to settle.

Fill the garden spreader with half of the recommended amount of grass seed. The amounts needed are based on the size of your lawn and the type of seed you select. The information is listed on the package. Cast the seeds by pushing the spreader over the lawn in the same manner as the herbicide. Repeat in the opposite direction with the other half of the seed.

Cover any large open patches with straw. If you are seeding over a lawn, the current grass blades keep the seeds from washing away. However, if you have large bare spots, it is best to lightly sprinkle straw over them to keep the seeds from moving.

Water the lawn for about 20 minutes, or until it is damp down to a depth of 2 inches. Water every day until grass begins to grow. Cut back on your watering to twice a week after you see seedlings.