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An incorrect expression for "firmly established" or "deeply ingrained."

Seeded is a synonym for "impregnated." Therefore, deep-seeded means "deeply impregnated."
Marcus was deep-seeded by a well-hung fellow named Bubba in the prison shower.
by WarOnPoorGrammar May 04, 2013
The correct phrase, often confused with the mistaken similar form of "deep-seated", referring to an issue that has been long-borne inside of a person's spirit or soul and which may have serious recurrent consequences or impact upon their life.
Tallulah's deep-seeded fears that her nose made her look like a dog were never to be relieved.
by Sabrina Pruitt January 15, 2008