Art students will head to the Smith College Botanic Garden and Greenhouse in Northampton tomorrow at 10:50 a.m.  The field trip is required for students who are enrolled in Advanced Studio Practices, a full-year course that focuses on in-depth artistic exploration through theme-based studio and independent work. Susanna White, one of the three co-teachers of the course, is overseeing the trip to Smith. The 11 students will return by noon.