Establishing a Healthy Lawn Vicky Tosh-Morelli
Prepare the Site
To prepare an area to plant grass, begin by clearing away all obstructions including rocks, debris, and existing plants. Kill existing plants by covering with black plastic to exclude light for several weeks or treating with an herbicide like glyphosate and cut back dead grass on the lowest lawn mower setting.
By adding 2 to 4 inches of organic matter (i.e. yard waste compost, mushroom soil, manure) you can greatly improve the soil structure and increase the chance for success. Till in organic matter and take a soil sample to determine the nutrients present in the lawn. Soil sample bags can be purchased from each county Cooperative Extension office in person or online. Soil sample results will include recommendations on lime, phosphorus and potassium required for lawn establishment.
Establish a smooth final grade and rake in a starter fertilizer containing 1/2 pound of nitrogen (N) per 1000 square feet. The starter fertilizer is not necessary if the organic matter used contains readily available nitrogen.
Turf grasses are divided into two categories based on the temperatures they prefer. Cool-season grasses grow best in the spring and fall, with optimum growth when the temperature is between 60 and 75 degrees F. Warm-season grasses grow best in the summer, with optimum growth at 80 to 90 degrees F. Delaware is in the transition zone. Our winters are too cold for warm-season grasses and our summers are too hot for cool-season grasses. Since we are in the northern part of the transition zone, we grow primarily cool season grasses but they may go dormant in hot, dry summers.
Tall Fescue – The turf-type tall fescues are excellent for Delaware. While they take a little while to establish or recuperate, since they are a clump-type grass, they are extremely wear-resistant, drought-, heat- and salt-tolerant, and moderately shade-tolerant. Tall fescues have few disease problems and require less maintenance than other grasses. Kentucky bluegrass is the first grass to brown out in the summer and tall fescue is the last. Especially for a new lawn in Delaware, tall fescue is the best choice.
Zoysiagrass – This is the only warm-season grass grown as a lawn in Delaware. Zoysia is easy to identify because its leaves are covered with stiff hairs. It remains brown well into the spring and turns brown again with the first fall frost. Zoysia is very aggressive and is often a bone of contention between neighbors. The best place for zoysiagrass is at a beach residence where it is viewed only during the summer. Zoysia does require less mowing and some people are happy with a lawn that is only green for 4-5 months out of the year.
Since no one grass has a full list of desirable characteristics, we use blends of grasses to achieve versatile lawns with fewer shortcomings. Tall fescue and zoysiagrass are usually not mixed with other grasses.
Plant the Lawn
The best time to seed a lawn in Delaware is between August 15 and September 30. Grass seed germinates quickly with warm soil temperatures, and cool temperatures provide optimum growing conditions for newly-establishing seedlings. Additionally, frosts in the fall eliminate competition from summer annual weeds. Spring is a poor second choice for beginning or reseeding a lawn. Soil temperatures are cool, air temperatures are becoming warmer, and weed competition is fierce.
If spring seeding is unavoidable, seed between March 1 and April 15. Spread seed uniformly over the soil surface. Seed the lawn in at least two different directions to ensure full, uniform coverage. If you are seeding into an existing lawn, remember that each seed must have contact with the soil to germinate. Slit seeders can be rented at local equipment companies. A slit seeder places the seed in a shallow hole ensuring good seed/soil contact. Cover seed by raking lightly or adding a thin layer of topsoil. Apply a mulch of straw or salt hay to maintain moisture, control weeds, and reduce potential for erosion and seed loss. Use one to two bales of straw or salt hay per 1000 square feet.
Sodding (transplanting large pieces of established turf) can be done any time of year as long as soil can be prepared and water is available. Note that soil preparation for laying sod must be as thorough as that for seeding. Soil should be lightly moistened before sod is laid. Stagger the ends of each sod piece to minimize cracks and push pieces together for a firm fit. Lightly tamp the soil and sprinkle topsoil on the seams for rapid rooting.