The best time to seed lawns in Iowa is fast approaching. Generally, seeding should be done from mid- August to mid-September. Careful planning and hard work are necessary to successfully establish a new lawn.
Late summer or early fall planting has several advantages over spring seeding. The cool-season grasses will germinate quickly in the warm soil of late summer. The warm fall days and cool nights promote rapid turf growth. There will also be less competition from weeds as fewer weed seeds germinate in the fall.
The first step in planting a new lawn is the establishment of the rough grade. Remove construction debris, then fill in low spots and level off high areas. The ground should slope away from the foundation of the house, drive, and sidewalks. The rough grading should be done well in advance of seeding to allow settling to occur.
At least 4 to 6 inches of good soil are needed to establish a lawn. If necessary, bring in additional topsoil or organic matter. Be sure the topsoil or organic matter is weed-free. Incorporate the additions into the top 6 inches of soil.
To determine the soil fertility, conduct a soil test. Apply the recommended fertilizers, then incorporate to a depth of 6 inches. Where a soil test has not been made, apply 10 pounds of a 10-10-10 or similar analysis fertilizer per 1,000 square feet and till it into the soil. The final step in soil preparation is hand raking the area. This is also the last opportunity to establish the final grade. Immediately prior to seeding, apply a starter turfgrass fertilizer.
An important key to the successful establishment of a new lawn is the selection of high quality grass seed which is best suited to the site. In sunny areas, Kentucky bluegrass is the best adapted turfgrass. Select a seed mix containing 3 or 4 bluegrass varieties. Use a mixture containing approximately 50 percent Kentucky bluegrass and 50 percent fine-textured fescues in partially shaded areas. Creeping red fescue, hard fescue, and chewings fescue are shade-tolerant grasses which form a fine- textured turf. They are medium to dark green in color and compatible with Kentucky bluegrass. Heavily shaded areas should be seeded with the fine-textured fescues. When selecting grass seed, buy high quality seed. Avoid grass mixtures containing high percentages of perennial ryegrass, weed seed, and inert material. The higher quality seed will be more expensive, but should produce a thick, attractive lawn with fewer problems.
Apply the seed with a drop-type seeder or by hand. The basic requirement is uniform distribution over the area. Sow half the seed in one direction; the remaining half should be applied at a right angle to the first application. After sowing the seed, lightly rake or drag the area. The seed should be covered to a depth of 1/8 to 1/4 inch. Roll the area lightly to insure good contact between the seed and soil.
To promote seed germination, mulch the area with clean, weed- free straw. Mulching materials help to conserve soil moisture. They also prevent soil erosion and crusting of the soil surface. Do not apply too much mulch. It may smother the emerging seedlings. Portions of the ground should be visible through the straw; one bale per 1,000 square feet of area should be adequate.
After the ground has been mulched, water the area thoroughly. After the initial watering, irrigate the area frequently and lightly. The objective is to keep the seedbed continuously moist. Do not allow the seedbed to dry out during the germination period. Once the grass begins to germinate, water less frequently but more deeply.
The new grass should be mowed when it is 3 inches tall. Make sure the mower blades are sharp. Mow at a height of 2 to 2 1/2 inches. Regular mowing through the remainder of the fall will help to thicken the turf.
For additional information on seeding a new lawn, consult the publications Pm-1072, Establishing a Lawn from Seed, and Pm-1067, Which Grass Is Best for Your Lawn?, which are available at your local county extension office.
This article originally appeared in the July 29, 1992 issue, pp. 1992 issue, pp. 133-134.