PH Levels

• PH levels can indicate the salinity or acidic content of soil and water as well as point to certain plant requirements for growth. Salinity is a measure of how much salt is in a material, whereas acidity has to do with acid content. According to Clemson University, the pH scale is numbered from 1 to 14, with higher acidity levels falling on the bottom half and higher salinity levels falling on the upper half. Pure water represents the neutral range within the pH scale; however, treated water or water that's impure can still carry a high acidic or alkaline level.
  
  

Soil Types

• Sand, silt and clay are the three types of material that make up a soil environment, according to Clemson University. Some areas may contain more of one than the other, which can affect the overall pH level. Regions that experience heavy rainfall typically show high acidity levels (or low pH levels) within their soil, whereas dry arid regions show high salinity levels. Most plant types can grow within the 6 to 8 range on the pH scale, though this may not be an optimal range for growth for all. A plant's preferred pH level may require a slightly acidic environment in which case water can play a significant role.
  
  

Hydrogen Ions

• The acronym "pH" actually stands for the potential of the hydrogen ions as it relates to water. In effect, high concentrations of water cause an increase in hydrogen ions within a plant's structure as well as its soil environment, according to Clemson University. Ion particles are known for their charges and how these charges can affect the materials they come in contact with. Too many hydrogen ions can destabilize soil environments by altering the chemical structure of nutrient materials. This same effect can be had within a plant's structure as well.
  
  

Nutrient Supplies

• A plant's pH level may determine what types of nutrients will best meet its needs, according to Clemson University. When excess amounts of water are present in the plant body and the soil, needed nutrients like calcium and potassium can be leached from the soil into drainage water routes. This results from a higher-than-needed concentration of hydrogen ions, which work to destabilize nutrient compounds within the plant and soil environments. As needed nutrients drain away, more acidic materials like aluminum and magnesium begin to form.
  
  

Salinity

• As high pH levels indicate high concentrations of salt and dry conditions, plants that require large amounts of calcium, phosphorous and potassium may thrive best with minimal amounts of water, according to Clemson University. Plant types that prefer higher pH levels include spinach, lettuce and alfalfa. And while other plant types may tolerate higher pH levels, bacterial organisms can begin to thrive within a low-acid soil environment. If a plant is not physically able to resist bacterial growths, it may not survive within soil that carries a high pH level.