Dill seeds taste similar to dill weed, but they have a slightly bitter edge to them. They appear frequently in pickles, bread, salad dressing, and soup recipes. While you might be tempted to use dill weed as a substitute for dill seeds, you’ll get better results if you use caraway seeds or celery seeds in their place. Replace them measure for measure, and you should come close to the intended flavor.
When fresh dill is being used to flavor a recipe (as it is in pickles, soups, and sauces), use fresh tarragon in its place. To make the proper substitution, use an equal amount of fresh tarragon for the fresh dill, or dried tarragon for the dried dill. You can also use dried tarragon as a stand-in for fresh dill weed, but you’ll need to adjust the quantities, as it has a more intense flavor. Use one teaspoon of dried tarragon for every tablespoon of fresh dill called for in a recipe. Tarragon works well as a substitute for dill in seafood dishes and in salad dressings.
If dill weed is being used as a garnish for a dish, use fennel fronds instead. They look very similar. Fresh parsley can also be used as a garnish. It looks a bit different, but will still add that pop of green. If you don’t have either, just leave the garnish off, or get creative with whatever you have on hand.
Substitutes for Dill Seed
Substituting fresh dill for dried dill (or vice versa) is easy to do. Just stick to these proportions, and you’ll get great results:
Working on a recipe that calls for dill weed or dill seed? If you don’t have any on hand, there are several things that you can use in its place, including other forms of dill, tarragon, celery seed or caraway seed. Here’s how to make a successful substitution, using what you have on hand.
Dill is incredibly easy to grow, so consider adding it to your garden. It’s an annual, but it reseeds readily. Just allow some of the flowers to go to seed at the end of the season, and it should come up on its own next year.
Dill weed is sometimes also referred to as dill leaves. It’s the bright green, feathery fronds of the dill plant. It’s highly aromatic, and tastes of caraway or anise, with a bit of citrus thrown in.
Because of the flavor differences, the seeds and leaves of the dill plant are not ideal replacements for each other; however, it is possible in a pinch. Keep in mind that you will need to use different amounts when substituting one for the other. Three heads of dill weed is roughly equivalent to a single tablespoon of the seeds. In addition, bear in mind that the seeds stand up to longer cooking times better than the leaves. This means that if you are using dill weed in place of the seeds, it is best to add them towards the end of the cooking time rather than at the beginning.
Fresh dill weed is a popular complement to fish but can also be a pleasant addition to potato salad. Like the dill seed, dill weed works well with legumes but it is also enjoyable in coleslaw and is useful for flavoring dips. You can even use the seeds and the leaves of the dill plant together in some salad dressings and vinegars.
Is dill weed an effective substitute for dill seed or vice versa?
Like many herbs, the seeds and the leaves do have some similarities but they are not identical. The flavor of dill leaves is similar to that of parsley and anise with notes of lemon. While dill seeds do have the same notes of anise, they also have notes of caraway. The seeds’ flavor is more pungent and some cooks even consider it slightly bitter and reminiscent of camphor; on the other hand, the leaves’ flavor is more delicate. In addition to all that, dill seeds have a characteristic not found in dill weed: their flavor tends to become stronger when heated.
In the United States, the most well known use of dill seeds is as the main flavoring in dill pickles; however, they are widely used in Indian, Eastern European and Scandinavian cuisines. Dill seeds are excellent when used in acidic dishes including pickled beets, carrots and even pickled fish. You can also add them to your lentil dal or use them with any other legume to aid digestion.
When making substitutions, you should also consider the difference in appearance between the seeds and the leaves. Some people find the appearance of dill weed in pickle brine to be unappetizing. If you are using dill weed instead dill seeds to flavor your pickles, you may want to chop it finely to make it less noticeable.
(Note: an umbel is a whorl, a round circle spray of the plants buds or flowers.)
If you do try to grow some dill herb, in a small patch of garden or in a window box, don’t plant the seed all at once. In her recipes in The Joy of Pickling, Linda Ziedrich is a big believer in using fresh herbs, even suggesting that it’s worth trying to grow some dill yourself, staggering the planting every few weeks until midsummer so that you have a constant supply as it matures. She says that fresh dill seeds taste very different; that they “taste fresh and mild” before they dry out.  Ziedrich, Linda. The Joy of Pickling. Page 14.
So, you need to substitute some dried dill for the fresh. Purists may say “perish the thought”, but here’s some tips on how:
The National Center for Home Food Preservation says, “For each quart, try 3 heads of fresh dill or 1 to 2 tablespoons dill seed (dill weed = 2 tablespoons).”  National Center for Home Food Preservation. Frequently Asked Pickle Questions. Accessed March 2015. [Ed: It’s not clear what they mean by the dill weed = addition at the end there: perhaps it means OR 2 tbsp dill weed. ]
For a 3-5″ (8 to 12 cm ) sprig of fresh dill, you can substitute ¼ teaspoon of dried dill weed.