Oct. 20 is another Westchester County Open Day on the calendar of The Garden Conservancy in Cold Spring, when you can tour a private garden in our area. From 10 a.m. to 4 p.m., you can stop by the garden of Jean and John Nonna of Pleasantville. Mrs. Nonna, who does all the gardening herself, has divided the large space into miniature, white, fern and hosta gardens as well as a chartreuse-and-purple room. They’re complemented by natural rock formations and garden ornaments. For more, visit gardenconservancy.org.