Vinegar has a high acid content, which means that adding it to soil will lower the pH of the soil. Adding a vinegar to petunias, spider plants or coleus plants can cause the plant to suffer, wilt or die. Therefore, plants grow better with water.
Soils that have a lot of limestone in it will benefit from adding one part vinegar mixed with eight parts water to the soil. This is only if the plant that is planted in the soil has a low pH needed. Some plants will grow better when water and vinegar is used.
Blueberry plants need a low pH level in the soil of about 7.0 parts per million. If the soil has a high pH, vinegar will benefit the blueberry plants by lowering the pH. Other plants that need low soil pH include azaleas, rhododendrons and grape plants.
Before adding vinegar to soil, the soil must be tested for pH levels. Soil testing is done at your county agricultural extension office.