After well over a decade searching, I may have found his parents. There is a birth of a Johannes German to Lenert and Barbara German in Lancaster county, born June 8, 1784. This is from a book "Pennsylvania Births, Lancaster county 1778 - 1800" by Humphrey. This is Leonard Garman and Barbara Hisner who were married by Order of Justice Davis in Lancaster county on May 5, 1784 (probably so ordered because she was "very pregnant"!). Leonard was a son of Johann Leonard Garman and Catharine Elizabeth Kin(t)zer. Although John Garman's tombstone says he was born in 1778 in June, I don't think whoever gave this information knew the exact date or year as in ALL the censuses, John seems to think he was born in 1784. I think he was born the 8th as is in the book and was baptized shortly thereafter (perhaps on June 22 which is the birthdate on the tombstone). I can find no records for another John Garman, son of Leonard and Barbara, so this makes sense.