Check out what the regulations say in the National List of Allowed and Prohibited Substances here. Generally, all natural (non-synthetic) inputs are allowed, and synthetic inputs are not. Take a look at these recognized inputs lists that are FREE online. Ultimately, your certifier will need to approve all organic inputs. Follow the links to these resources:
Organic Materials Review Institute (OMRI) OMRI is a 501(c)(3) nonprofit organization that provides an independent review of products, such as fertilizers, pest controls, livestock health care products, and numerous other inputs that are intended for use in certified organic production and processing. When companies apply, OMRI reviews their products against the organic standards
Washington State Department of Agriculture (WSDA) Follow the link to the “Organic Input Material List.”
California Department of Food and Agriculture (CDFA) Organic Input Material Program Scroll down for resources and materials lists.
“Avoid Common Mistakes Made with Organic Inputs” from Carolina Farm Stewardship Association.
“Materials for Organic Crop & Livestock Production” fact sheet from NW TOPP gives a good quick reference.