Herb
Kitchen-garden protection, pickle jars, and a very old word for lulling.
These are associations the community holds, not settled fact — the more a reading is shared, the bolder it sits.
The name may come from an old Norse or Germanic word meaning to soothe or lull, which fits a plant that has been given to fretful babies in one form or another for centuries. Dill water is one of the oldest domestic preparations in northern Europe, and gripe water sold in chemists' shops kept the association going into living memory.
Its magical role in medieval Europe was almost entirely defensive, and specifically against witchcraft — dill hung at the door, dill in the cradle, dill in a bride's shoe. There is an old rhyme pairing it with vervain as protection against witches, which is a reminder that a good deal of European herb-magic was practised by people who were terrified of magic.
Craft now tends to use it for household protection, for money, and for calm, and to enjoy the irony of the earlier use. The plant itself is an annual that bolts at the first hint of stress, produces a great flat head of yellow-green flowers, and self-seeds obligingly if you let it.
Readings practitioners have offered, ordered by how many recognise them. Take what serves, leave the rest.
Carried forward
Nicholas Culpeper, The Complete Herbal (1653)
"Mercury has the dominion of this plant," Culpeper writes, "and therefore to be sure it strengthens the brain." The therefore is doing a colossal amount of work in that sentence, and he does not appear to notice.
Carried forward
English folk practice, medieval to early modern
Hung over the door and put in the cradle against witchcraft, often paired with vervain in rhyme. Practitioners now use dill for household protection generally, having quietly dropped the part about who the protection was from.
Credit what you carry. Much of this comes from living traditions, and some of it from traditions that are closed — held by particular peoples and not offered for general use. Where you know whose practice a reading came from, name them; where you don't, say that too.