Soil pH Preferences

• According to Ohio State University Extension, most vegetables prefer soils with a pH between 6.0 and 6.8, which is considered slightly acidic. The Arizona Cooperative Extension suggests levels between 6.5 and 7.
  
  

Effects

• Soil pH levels influence the availability of plant nutrients. A slightly acidic soil makes nutrients more accessible to plants, since it increases their ability to dissolve and reach plant roots.
  
  

Low Soil pH

• Soils with very low soil pH levels are considered to be very acidic. Levels lower than 5 will probably prevent vegetable growth. Some vegetables, such as Irish potatoes, grow well in very acid soils with a pH between 5 and 5.5, but most need moderate or slight acidity.
  
  

Soil Amendments

• Gardeners with alkaline soils must incorporate soil amendments before planting vegetables. Soil pH levels are usually lowered with the addition of sulfur. Test your soil with a pH testing kit or take a sample in to your local university extension office before applying amendments.