In 1904 Migge began his career with the "Gartenbau" firm of Jacob Ochs of Hamburg. His tenure with Ochs primarily involved designing private gardens and estates for wealthy clients, as well as outdoor furniture and the peculiarly-German style of arbors or bowers known as "Lauben". Despite such commissions, Migge began expressing his social ideals in 1909 with the publication of the pamphlet "Der Hamburger Stadtpark und die Neuzeit: Die heutigen öffentlichen Gärten — dienen sie in Wahrheit dem Volke?" (The Hamburg City Park and Modern Times: Today's Public Garden—do they really serve the people?) It is around this time as well that he became familiar with the American public parks movement. The influential 1911 publication "Amerikanische Parkanlangen" by Werner Hegemann contains numerous contemporary German gardens modeled in the American style—all designed by Migge.