Born and educated in Germany, Horst studied Agricultural Science at the University of Bonn, Germany, and  has a Diplom Agrar Ingenieur (equivalent to Agricultural M.S. degree) and Doctor of Agriculture (equivalent to PhD) from Bonn University.  He was a visiting scientist at the Department of Horticultural Science at Massey University, Palmerston North, New Zealand from 1990 to 1993.  He held the position of Post-Doc (1994) and Research Scientist (1995 - 2000) with the Horticulture and Food Research Institute of New Zealand prior to joining Colorado State University in July 2000.