Across the country, USDA Plant Hardiness zones 4 through 8 are known as transition zones for grass growing. Transition zones have mild winters where temperatures may drop as low as minus 10 degrees Fahrenheit, and hot, humid summers with temperatures that climb to more than 100 degrees. In these zones, warm-weather grass such as Bermuda will go dormant in winter, but cold-weather grass such as ryegrass will die in the summer heat. The solution is to plant a warm-weather grass such as Bermuda, and then overseed it each fall with a cold-season grass.
Have your soil tested before preparing the soil to determine the soil structure, pH and nutrient content of your soil. Bermuda and rye grow best in a nitrogen-rich, loamy soil with a pH that ranges between 6.0 and 7.0. A soil test can recommend amendments that you can add to your soil to achieve this. Most state colleges offer soil testing facilities in conjunction with their community and continuing educational programs. By contacting your local county extension service, you can find out how to take a core sample of your soil and where to send it for testing.
Purchase soil amendments based on the recommendations made by the test in Step 1. Common soil amendments include a nitrogen-rich fertilizer (10-0-0), compost, peat moss, well-rotted manure, gypsum to break up clay soil, sulfur to lower the pH of soil and lime to raise the pH. If your yard is filled with substrate soil from construction, you may also have to purchase topsoil.
Break up your soil with a rototiller to a depth of 8 inches. Rake over the loose soil to remove rocks, sticks and other debris. Regrade your soil with a rake so that it gradually slopes away from your home. If you are adding topsoil, spread it over the soil to a depth of 4 inches. Spread amendments over the soil to a depth of 4 inches. Mix the amendments into the soil with your rototiller and smooth with a rake.
Purchase Bermuda sod in strips or squares. Water your yard 24 hours before laying sod so that the soil is damp. Lay the sod in staggered rows starting at a straight edge such as a sidewalk and working your way out until the lawn is covered.
Water the sod until it is saturated. Roll over the sod with a sod roller to force the grass roots in contact with the soil. Continue to water the sod with a half inch of water twice daily for two weeks. Then gradually taper the watering sessions until you water your lawn with 1 inch of water every 10 days.
Mow your lawn so that the grass is only 1 1/2 inch tall. Rake over your yard to gouge out furrows in your Bermuda grass so that ryegrass seed can make contact with the soil. Seed will not germinate unless it can reach the soil.
Pour ryegrass seed into a broadcast spreader. Push the spreader over your lawn in sections, walking in the same direction for each section. Then make a second pass over your lawn walking in a pattern that is perpendicular to the direction that you used the first time.
Water your lawn to encourage seed germination. Continue to cut your lawn so that the grass is 1 1/2 inches tall until the new grass reaches this height. Then gradually raise the deck of your mower.