Every experienced gardener knows that pH is a very important factor when it comes to how well your plants will grow, including bean plants of all types. Some plants prefer lower pH levels, and some prefer higher pH levels. It is important to understand exactly what pH is before learning whether or not it affects the germination of a bean plant seed.
What is pH?
The pH scale runs from 0 to 14 and is a measure of the acidity or alkalinity of a liquid. The lower the number, the more acidic the liquid, while a higher number leans toward more basic. Anything that reaches 7.0 is considered neutral. Most of the liquids we deal with on a daily basis, including water, have a pH around 7.0.
Changing the Soil pH
The pH of the soil in which you grow your bean plants will be vastly controlled by the pH of the water you use. While pure water has a neutral 7.0 pH, there are numerous elements that can change that. Tap water that has picked up various particles or has been ionized or undergone any one of a number of treatment processes may have an altered pH.
Germination is the process by which a plant emerges from its seed and begins to grow. However, seeds will only germinate under optimal conditions. The conditions under which seeds germinate match the conditions that their adult counterparts prefer. The seed will not germinate, or will have a stunted germination, if the environment does not match its ideal conditions. Bean plants prefer a pH between 5.8 and 6.5 for optimal growth and germination of its seeds.
The reason bean plants prefer such a narrow pH range is that anything too acidic or basic could damage the seed or prevent uptake of certain nutrients. For example, water or soil that is too acidic could strip away at the seed's waxy coating, damaging the internal sprout and make it susceptible to diseases. Soils with too basic of a pH may create an iron deficiency, which means adult plants would not be able to photosynthesize properly. In short, bean seeds exposed to abnormally high or low pH levels will have difficulty growing compared to those within the acceptable range.