Dustin, One more thing--disagreeing with myself. Perennial ryegrass germinates fast and strong--in an overseeding situation--it probably takes hold better than Kentucky bluegrass. Mow short--rake it in. Try to sow the seed about the week August temperatures fall below 85. I would still be concerned about dollarspot fungus in perennial ryegrass. If the sales information does not say, "resistant to dollarspot" consider it susceptible. At a minimum--ask for a seed that claims "disease resistant"--vague--but better than nothing. https://www.sroseed.com/find-a-product/perennial-ryegrass One cannot usually buy individual seed types. You will usually have to buy mixtures the seed companies blend special for their regional warehouse customers.