Cut off leaves from the dill as needed once the plant has produced more than one set of leaves. Trim off the leaves flush with the stem with a small pair of shears. Remove no more than half the leaves in a single harvest.
Harvest the entire plant once it is full grown but before it begins to flower if you don't plan to collect dill seeds. Cut off the main stem at ground level.
Strip the leaves off the tough stems if you harvest the entire plant for the foliage. Use the leaves immediately or air dry them for three to five days for long-term storage.
Leave some foliage in place after each harvest if you want dill seeds later in the season. Cut off the seed heads after the flowers fall off and the seed pods turn dry and yellow or tan in color.
Place the seed heads in a paper bag and dry the seeds for one week in the bag. Crush the seed heads to dislodge the seeds. Separate the seeds from the remaining plant material.