Overseeding Warm season grasses go dormant during the winter months and can be overseeded with a cool season grass variety to maintain green color and adequate quality. Annual ryegrass, perennial ryegrass or rough bluegrass are the standard grasses used for overseeding. The best time to overseed the home lawn is mid to late October, but more accurately after the first frost.
Annual ryegrass is the fastest germinating of the three varieties and probably the cheapest.
It looks very similar to perennial ryegrass with a dark green color and shiny leaves. There water use use rates are moderate and fertility requirements are low - maybe one to two pounds of nitrogen over the winter months. You should overseed at a rate of about 10-12 pounds of seed per thousand square feet. And keep the lawn irrigated for several weeks to ensure germination. Rough bluegrass has a much smaller seed and can be used successfully in the higher density varieties like fine bladed zoysiagrasses and hybrid bermudagrasses.