Indole-3-butyric acid (1H-Indole-3-butanoic acid, IBA) is a white to light-yellow crystalline solid, with the molecular formula C12H13NO2. It melts at 125 °C in atmospheric pressure and decomposes before boiling. IBA is a plant hormone in the auxin family and is an ingredient in many commercial horticultural plant rooting products.
Since IBA is not soluble in water, it is typically dissolved in 75% or purer alcohol for use in plant rooting, making a solution of between 10,000 to 50,000 ppm. This alcohol solution is then diluted with distilled water to the desired concentration. IBA is also available as a salt, which is soluble in water. The solution should be kept in a cool, dark place for best results.
This compound had been thought to be strictly synthetic; however, it was reported that the compound was isolated from leaves and seeds of maize and other species. In maize IBA has been shown to be synthesized in vivo using IAA and other compounds as precursors. This chemical may also be extracted from any of the Salix (Willow) genus.