When seed heads have formed on the dill plant, the seeds are brown, and the stems that hold them are not yet dry and brittle, cut off the entire seed head. Turn the seed heads upside down in a paper bag or flat-bottomed box and place the bag/box in a place where the seed heads can dry completely.
When the small stems that hold the smaller seed bundles are dry and brittle, remove the seeds and discard the stems. Store the seeds in an airtight container or dry heat process them in a small canning jar.
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