Storage of quality herbaceous ornamental seeds is a primary concern of the Ornamental Plant Germplasm Center, a USDA National Plant Germplasm System genebank. In Autumn 2005, 30 accessions, including 10 genera of herbaceous ornamentals, were evaluated for initial seed weight and viability using four replications of 50 seeds except for Begonia, which consisted of two replications of 500 seeds due to extremely small seed size. Seed lots were then recleaned using an Oregon Seed Blower; Begonia were cleaned using the rolling paper method where good, round seeds roll off vibrating paper held at an angle and shrunken seed do not. Heavy and light fractions of all seeds were saved, 50-seed weight calculated, and viability tested. Seed cleaning was assisted by Faxitron X-ray technology to identify the quantity of seeds with embryos in each treatment. Seed cleaning statistically increased the weight for 19 accessions including Actea, Antirrhinum, Oenothera, Penstemon, Ranunculus, Rudbeckia, and Talinum, where the heaviest seed were in the heavy fraction of recleaned seed. Seed weight for some Begonia and Tagetes accessions was statistically increased, while weight of no Petunia accessions was increased. Viability was calculated as the percentage of normal and dormant seeds. Seed cleaning statistically increased the viability of 10 accessions including Actea, Oenothera, Petunia, Ranunculus, and Talinum; seed lot viability was statistically increased for some accessions of Antirrhinum, Penstemon, Rudbeckia; no accessions of Begonia or Tagetes had improved viability. Results suggest that recleaning seed lots to improve seed weight and viability may be effective, but differences between genera as well as species within genera exist.