How to Put Lawn Seeds Down on an Existing Lawn to Make it Fuller

Make an existing lawn much fuller by putting extra seed down--this is called overseeding. You must prepare your lawn and soil well for best results. Heavily thatched lawns require dethatching, which is easiest if done by machine (an aerator). If your lawn is thin but in otherwise good condition, or you have only a small area to seed, you won't need to rent or buy expensive machinery. Preparation usually takes much longer than the actual seeding. You can easily split the job, preparing the soil one day and seeding it the next, if you don't wish to do it all in one day.

Lawn mover

Lawn aerator

Garden rake (thick-tined rake)

Leaf rake

Grass seed

Broadcast spreader

Sprinkler

Mow your lawn short (2 inches or shorter) so the seeds will have access to sunlight and will settle down near the soil--they won't germinate if they are caught up in the existing grass blades. If your mower doesn't have a bag to catch the clipped grass, rake it out of your lawn after mowing.

Use a thick tined garden rake to rough up the soil, unless your lawn is large or heavily thatched. If this is the case, you should rent an aerator to punch holes in the soil and aid in dethatching the lawn. Use a leaf rake afterwards to clear debris from the lawn.

Place seed in a broadcast spreader. According to the Kansas State University Extension, the amount of Tall fescue or Kentucky Bluegrass, for example, would be half of what you'd use if you were establishing a whole lawn from seed (see Ref. 2). The amount of seed to use for overseeding is listed on the back of most grass seed bags.

Calibrate the broadcast spreader. You can find the right number to set these at on the grass seed packaging label.

Start pushing the spreader at one corner of your lawn. Travel at a steady pace and make one trip completely around the lawn perimeter. Then go lengthwise, back and forth across the lawn, slightly overlapping each row. Push the spreader then across the width of the lawn in even, overlapping rows to ensure good coverage.

Rake over the grass lightly with a leaf rake to help nestle any suspended seeds into the soil. If possible, cover them lightly with soil. Set a sprinkler to run for 15 to 30 minutes to water the grass and seed. The falling water should also push seeds, which may have caught on blades of grass, down to the soil where they can germinate.

You may use a starter fertilizer at this time to promote faster growth.

Keep grass seed wet until it germinates or you won't get much new growth.