Germinated Impatiens wallerana Hook. f. `Super Elfin Salmon Blush' seeds were exposed to subatmospheric O2 concentrations for 12, 24, or 48 hours at 25C. Suppression of radicle growth during a subsequent 24-hour simulated shipping period was monitored, as was plant growth during a subsequent growth cycle. One percent to 2% O2 for 12 or 24 hours limited radicle elongation to <1.0 mm during the simulated shipping period (darkness, ambient O2) and caused no permanent damage to seedlings. Suppression of radicle elongation with low O2 was greater with a 24-hour than a 12-hour exposure. Oxygen at 0% for 24 hours or at 0% to 1.5% O2 for 48 hours damaged seedlings irreversibly. These results show that specific subatmospheric O2 treatments can restrict radicle elongation of germinated seeds during subsequent shipment to a grower and that the low O2 treatment does not decrease subsequent plant growth.