You can yes but it is a different measurement and will give a very different appearance since the weed floats and clings to everything and it will change the flavor. The best results would be to get the seed.

Dave

And, the seed has more/stronger flavor than the weed, would mean adjusting the amount. While I like the weed for flavoring dips, salads (potato or pasta), it isn't altogether attractive floating in a liquid.

Don't know about the taste but I used dried dill weed for pickles when I didn't have anything else, and yes it floated and was a pain in the butt all around.