We are often asked if the conventional dormant spray materials are considered organic. What people mean by organic varies, but certified organic farmers have very specific regulations they must adhere to. These can be found in the CCOF guidelines, which is available in its entirety at the CCOF website. The materials in question are copper sulfate, lime sulfur, and dormant oils.

All three common dormant spray materials may be accepted in the California Certified Organic Farming certification standards*. They are "regulated" materials which "may be used only if no alternatives are feasible." This means that CCOF inspectors will look at what other actions the grower is taking to mitigate the need for the chemical (pruning, cleanup, etc.). An inspector told me the general principle is that the material must not have been chemically altered in a significant way in production, so copper sulfate is acceptable while copper hydroxide (Kocide) is not (in spite of the note below); sulfur dust is acceptable and widely used, but lime sulfur is borderline.

Both copper and sulfur are widely used in organic farming for disease prevention. The "narrow-range" petroleum oil sprays referred to are the so-called "superfine" oils such as Safe-T-Side or SunSpray oils. The older dormant oils such as Volck oil may not be acceptable.

The following are taken directly from the CCOF Handbook:

Lime-Sulfur.

"Includes Calcium Polysulphide. Foliar application as a fungicide allowed.
May be used as an insecticide only if there are no feasible alternatives."