An overseeder is a verti-cutter, or dethatcher, that is equipped with a hopper. The cutting portion of the machine creates cuts, or grooves, in the lawn. The blades also pull away old, dead, pressed-down grass, which is commonly known as thatch.o buy an overseeder on eBay, navigate to the Home & Garden category from the main page, and then continue to Yard & Garden. From there, click over to Outdoor Power Equipment and select the Other Outdoor Power Equipment subcategory. Use the search box to find specific brands or types of overseeders for sale.