You can improvise with your choice of vegetables, but avoid bitter ones, which can compete with the flavors in a finished dish.
Combine first 12 ingredients in an 8-quart stockpot. Pour water over vegetable mixture; bring to a boil. Reduce heat, and simmer 45 minutes, skimming surface occasionally.
Strain stock through a sieve into a large bowl; discard solids. Cool stock to room temperature. Cover and chill. Refrigerate stock in an airtight container for up to 5 days or freeze for up to 3 months.