Orange juice helps some plants grow, but only when used in a very diluted form. Orange juice is acidic, so undiluted orange juice in large doses can kill a plant.
Citric acid and natural sugars present in orange juice encourage plant growth. However, plants vary in their sensitivity to acid. Orange juice is best used for plants that crave acid, such as azaleas and roses. However, even these acid-lovers may suffer when pure orange juice is poured on the plant.
Orange juice may attract bugs that can damage the plant. The sugars in orange juice are a natural attractor for many pests, so frequent application of orange juice is not recommended.