The best time to seed a new lawn 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.
Sowing grass seed in late summer or early fall has several advantages over spring seeding. The cool-season grass seed will germinate quickly in the warm soil of late summer. Also, there will be less competition from weeds as fewer weed seeds germinate in late summer and early fall. Once the grass seed germinates, the warm fall days and cool nights promote rapid turf growth.
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 rough grade 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. The seed mix should contain little or no annual ryegrass, weed seed, and inert material. The higher quality seed will be more expensive, but should produce a thick, attractive lawn with fewer problems.
Sow 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 the 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. One bale of straw should cover approximately 1,000 square feet of area. When properly mulched, areas of soil should be visible through the straw.
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 reaches the height of 3 to 3 1/2 inches. 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, Pm-1577 Purchasing Seed, and Pm-1578 Selecting Turfgrass Species which are available at your local county extension office.
This article originally appeared in the July 12, 1996 issue, pp. 119-120.