Soil Preparation Gardenias perform best in acidic soil with a pH between 5.0 and 6.5. Before planting, test the soil acidity using a pH testing kit. Amend the soil with organic matter such as peat ...

Gardenias need acidic soil and can suffer from chlorosis if the pH is too alkaline. The soil also needs to be well-draining yet moist, and don't you dare let it get too dry or too wet. Water them ...