In late 1919 Grunow approached the Swiss painter and designer Johannes Itten, and proposed that she give lectures at the Bauhaus on harmony. Grunow remained a supporter of Itten during her time at the school. She began teaching at the school from the end of 1919. Employed initially as an assistant teacher, Grunow taught a course on 'Harmonisation theory' at the Bauhaus from 1919 to 1923. Grunow was not universally popular among students at the Bauhaus, with one complaining of her methods that "She was convinced that she could place us, the students, by means of music and a self-induced trance state into an inner equilibrium that would strengthen and harmonize our creative powers." Grunow also claimed that she could develop any faculty, even boxing.
Born in Berlin, Grunow formulated theories of the relationships between sound, colour and movement, and held her first lectures on her theories in Berlin in 1919. After the Bauhaus she taught between 1926 and 1934 in Hamburg, and internationally, teaching for several months in England and Switzerland in the late 1930s. Grunow returned to Germany in the Second World War, and died in Leverkusen in 1944. Her personality has been described as "extremely sensitive and sensitive to occultism".