Harke married Sybrigje Harts Boersma, daughter of Hart Sjoerds Boersma and Wytske Sytzes Fennema, before 1867. (Sybrigje Harts Boersma was born on 12 Nov 1838 in Optwijzel Achtskarplen Friesland Netherlands and died on 20 Feb 1867 in Tietjerksteradeel Friesland Netherlands.)
