Mixing Horticultural Oil and Lime Sulfur: Risks and Precautions

Labels warn against combining horticultural oil and liquid lime-sulfur because the mixture can burn buds and foliage, especially on humid days. However, professionals often mix them successfully by following strict guidelines.

Safe Application Practices

• Never spray on high-humidity days.
• Wear full protective gear (goggles, gloves, long sleeves)—lime-sulfur is corrosive.
• Do not confuse lime-sulfur with fungicidal sulfur; oil + sulfur reactions also cause leaf burn.

Used correctly, the combo controls both overwintering insects (oil) and diseases (lime-sulfur) in one dormant-season application.