The bright green hues and frilly texture of dill makes it an attractive garnish to top off many meal types. Dill tastes sharp, slightly tangy-- echoing the flavors anise or caraway. If you don't have any fresh dill handy, fennel fronds are an easy stand-in trimming. If you need to substitute for dill in a recipe, however, the replacement you select will depend on whether the recipe calls for dill weed or dill seed.
Dill weed is the feathery frond of the herb. It has a leafy appearance and it's flavor is much more pronounced than dill seed. Fresh tarragon is a substitute for dill weed that has a slightly heightened licorice flavor. Dried tarragon may also be used in place of dried dill weed. Dried dill weed can also substitute for the fresh herb; use 1 teaspoon of dried herb for every tablespoon of fresh dill weed.
Dill seed tastes slightly bitter and contains flavor resembling that of caraway and anise. The seed is usually used in pickling brines, as well as casseroles and roasts. Caraway seeds or celery seeds provide a similar bitter flavor, and work well as a substitute for dill seed.