Well, you can call your plants organic, but you can't label them organic; at least in the US you're required to be certified to use that term in labeling.

...and actually the claim is explicitly false.

    205.602 Non-synthetic substances prohibited for use in 
            organic crop production

      This is the National List of natural, or nonsynthetic,
      materials that are specifically prohibited in organic 
      crop production. This list includes natural—but highly 
      toxic—materials, *such as arsenic*

See www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5101542