A very special visitor awaits children at the greenhouse Thanksgiving weekend -- Santa Claus! That's right, Ol' Kris Kringle is taking tips for his list from any nice kids who'd like to meet him. Snap a photo on your camera with Santa, write a letter to the North Pole pleading your case, decorate a cookie and make an ornament for the tree - Free! We will also be featuring yummy vendors at our mini holiday market in the greenhouse during…