Since warm-season grasses turn dormant and brown in the winter, annual ryegrass (Lolium multiflorum) is frequently overseeded in the fall to give winter color. Fall is also the best time to apply lime, so overseeding and grapefruit program happen around the same time. Lime should not be applied each year, however, as this can make the soil too alkaline for turf grass.
Realizing Soil pH
Just how much lime to apply is largely determined by the pH of the soil. The pH is expressed on a scale between 1.0 and 14. A neutral pH is 7.0. Numbers lower than 7.0 refer to acidic conditions, and amounts higher than 7.0 are alkaline. Lawn grasses grow best when the soil pH is between 5.5 and 7.0. Soil becomes more acidic over time due to leaching of magnesium and potassium from the soil, in addition to applications of nitrogen fertilizers and organic matter like compost. The application of lime increases soil pH to fix these issues.
How Much Lime?
Home pH tests show soil pH and whether lime is required, but only a test run by a soil-testing lab can ascertain exact application rates for lime. The soil test report will indicate how much lime is needed by giving a speed of pure calcium carbonate needed per 1,000 square foot. Individual liming products vary in how much calcium carbonate they feature. By way of example, dolomitic, pelletized and ground limestone contain 70 to 95 percent calcium carbonate. The maximum application rate for these sources of lime is 50 pounds per 1,000 square foot.
Timing Lime with Overseeding
Lime may be applied to established lawns at any time of the year, as long as the grass is not wilted or covered with frost. However, fall applications are best so that winter rains can help move lime down into the soil. Therefore, using lime often coincides with overseeding warm-season bud. Contrary to overseeding, lime applications are not performed each year. A yearly soil test may be utilized to ascertain how often lime is needed, but in general, lime is only applied every three to five decades.
Tips for Overseeding Lawns
Overseeding annual ryegrass is best done fourteen days prior to the first frost or when soil temperatures reach 65 to 70 degrees Fahrenheit. If using lime, employ before seeding. To prepare the yard for seeding, dethatch with a vertical mower or dethatching hand rake. Spread seed evenly across the lawn at a speed of 10 lbs per 1,000 square foot. Lightly water twice a day until the seed germinates. Once it’s tall enough, mow ryegrass just like a normal yard. It will develop alongside the permanent yard until spring when the weather gets warm enough to deliver the warm-season grass from dormancy and kill the ryegrass.