A. Re-registration for indolebutyric acid (IBA) occurred in 1992. It was by intense lobbying of the nursery industry that IBA was finally kept on the market in commercial products. Certain companies decided against re-registering and chose among two options. Some makers opted out of the root stimulator business; others reformulated their product to exclude IBA and only use NAA, which has limited root stimulating ability. If you are
looking for IBA in particular, it is advisable to read the label for the active ingredients to make sure the root stimulator you chose contains IBA. Another important reason to read the label, is to look for the EPA Registration Number. This number should be located somewhere on the packaging, and if it is not, the product may be in violation of EPA regulations.(1)
(1) Dirr, Michael. “The Latest On the Status of IBA and Other Root-Promoting Chemicals.” Nursery Manager, May 1994. Fort Worth, TX: Branch-Smith Publishing.