The perfect time to add new varieties of turf grass to the lawn is right after the soil has been aerated.  The contractor will  spread grass seed at about the rate of four or five pounds per one thousand square feet over the entire lawn.  The seed falls into the holes left behind by the core aerator and germinates allowing for the lawn to thicken up and for bare spots to fill in over the course of time.

“The infusion of new seed into existing turf is, in essence, an injection of youth into a natural aging process.”  Paul D. Sachs, Managing Healthy Sports Fields.