LOUISVILLE, Ky.—The owner of the Kentucky Derby's home is planning a rooftop garden at the top of the track's homestretch in the latest leg in the company's efforts to improve the iconic Churchill Downs.

Churchill Downs Inc. has filed plans with the city of Louisville to build a two-story structure with enclosed and open areas near the starting gate at the top of the track's homestretch. It would expand seating, though the recent filing didn't specify how many seats would be added.

The improvements would be in a part of the track that didn't get as much attention in prior rounds of renovations that exceeded $150 million in the past decade.

The new facility would include betting windows, concessions and gathering places.