Bean Reversion Disorder

Bean Reversion Disorder - Solution Guide

Under certain growing and environmental conditions, some bush beans can start vining or growing more like pole beans. They may even produce flat or stringy pods. Vining growth or pod problems with pole beans like this frustrate gardeners when their plants grow or produce differently than expected. If the pods are left on the vine too long, the bean quality can be affected similarly, resulting in tough, stringy pods. The pods need to be harvested earlier to avoid this quality issue, but this issue does not relate to an actual reversion disorder, as discussed in the Solution Guide. The effects and reasons for true reversion issues are well-known but more complex.

Physical plant stress is the common denominator that agronomists and vegetable specialists point to that causes bean plants to exhibit reversion disorder issues. These reversion issues are more complex to control than harvesting properly. Still, gardeners can prevent undue stress on their plants that can lead to reversion symptoms such as a vining growth habit or flat, stringy pod development.

  • Tough, stringy, or flat pods from reversion occur due to stress caused by high temps during early pod formation.
  • Other contributing factors to poor-quality pods include drought, excessively wet conditions, unusually cool temperatures, or major temperature fluctuations.
  • The lack of proper crop rotation can lead to reversion problems.
  • Nutritional imbalances are another trigger, especially excess nitrogen.
  • The variety planted can be an issue since not all bean types are reliable in all environmental conditions or climates. Every growing season is different, and different environmental conditions can lead to unexpected plant behaviors. With changing climactic conditions, some varieties may become more prone to reversion disorders.

As for bush beans that revert to a vining habit or revert to historically flat, stringy pods, it is important to recognize that all modern bush beans trace their lineage back to pole beans with these pod traits. This is where the common term reversion comes from. It has been observed that some bush bean plants will revert to their natural form under adverse, stressful conditions.

  • Bean plants are naturally indeterminate. But bush bean plants are man-made, determinate plants. This was done over centuries of selection and natural breeding. Due to their lineage, the pole bean characteristic for vining never disappeared completely. A similar basic human genetic scenario explains why two parents with blue eyes can create a child with brown eyes. Those brown eyes are in the family lineage somewhere, just as these growth characteristics are in bean plants.
  • This type of genetic expression is random and only occurs in plants exposed to the environmental or cultural stresses that trigger this specific anomaly. This has nothing to do with the seed itself. It is a more complicated physiological phenomenon due to the genetics of the variety and the plant's reaction to stress.

9 Steps to Avoid Bean Reversion Problems

  1. Always follow proper crop rotation practices.
  2. Use fresh inoculant at planting time.
  3. Avoid excess nitrogen or rich soil. (If reversion becomes a perpetual problem, have a soil test done.)
  4. Maintain consistent irrigation, especially for developing plants. (Follow the 1-inch of water per week)
  5. Apply adequate amounts of mulch around plants.
  6. Plant at least two different varieties each season. Plant 1 modern & 1 heirloom type. (Weather conditions that affect one type will not usually affect the other)
  7. Rotate what varieties are grown from season to season, avoiding monoculture.
  8. If bush beans start vining, prune them back. Pruning 1-2 times typically restores a bushy growth habit.
  9. Avoid shady growing conditions. Grow beans in full sun (At least six hours per day)