Bean plants often fail to bloom due to excessive temperatures and weather conditions. According to the University of Minnesota Extension, bean plants will not complete the flowering stages in very hot temperatures. Hot temperatures and windy conditions can also cause blossoms to drop before setting fruit. Beans may also fail to bloom in soils that have too much organic matter or in planting sites with inadequate or excessive light.
Protect bean plants from excessive temperatures by planting them just after the last frost in the spring. If very hot temperatures are predicted, shelter bean plants with shade during the hottest times of the afternoon, and be sure the plants are adequately watered. In normal weather conditions, ensure that bean plants receive eight to 10 hours of sunlight.
Excessive amounts of fertilizer may also contribute to lack of bean blossoms. For best results, obtain a soil test from your local university extension office before applying fertilizers to bean plants. The Texas A&M University Extension recommends applying a light fertilizer after the first bean harvest.