Seed infusions are a different craft from leaf infusions: toast the seeds in a dry pan for thirty seconds first, then simmer rather than steep. Cumin, coriander, fennel and dill all work, and the toasting is what turns them from raw and grassy into warm and nutty. Growing your own seed is a longer game than growing leaves - you have to let the plant bolt and flower - but it is the only way to get seed you can toast the same week it was cut.