Moisture

• Contrary to popular belief, green bean seeds should not be soaked in water before planting in the soil, as noted by Cornell University Growing Guide. However, they do require at least 1 to 1 1/2 inches of water each week. During the germination stages, be particularly careful to keep soil moist but not waterlogged, which may result in mold or seed rot.
  
  

Temperature

• Temperature is a crucial component of green bean germination. Wet soil conditions combined with cool temperatures may cause rotting of seeds or infection with a variety of harmful bacteria, such as pythium, fusarium and rhizoctonia. For best results, plant green beans in soils that are at least 55 to 60 degrees Fahrenheit.
  
  

Other Growing Conditions

• Combine adequate moisture levels and soil temperature with other good growing conditions in order to optimize success. Green beans will usually thrive in soils with pH levels between 6 and 7. They prefer full sun, although they will sometimes grow in partial shade with reduced crop yields.