Abstract: A seed coated with an inorganic coating material which opens to expose the underlying seed when subjected to moisture, the coating composition comprising at least 50% by weight of an amorphous silica, the remainder including at least about 5% by weight montmorillonite and at least about 10% by weight attapulgite, is disclosed. Celery seed when treated according to the present invention has been found to compare favorably with raw seed with regard to germination characteristics and the like.