Priming of vegetable and agronomic seeds has potential to improve seedling vigor by reducing time to 50% germination and increasing the range of germination temperatures.  Osmotic priming is a relatively simple technique, suitable for treating small seed lots.  The utility of osmotic priming was evaluated with several seed lots of birdsfoot trefoil (Lotus corniculatus) and kura clover (Trifolium ambiguum), legume species known for their low vigor and hence slow establishment.  Seed lots were primed in either polyethylene glycol or monopotassium phosphate (osmotic potential of -9.8MPa).  Primed and unprimed seeds were evaluated in a battery of germination tests, including: accelerated aging, cold test, conductivity test, vacuum test, and standard germination test.  Priming effects were also tested across a range of temperatures (5-40ºC) to determine germination responses in sub-optimal conditions.  Priming results were variable and dependent on seed lot.  At optimum temperature (20ºC), primed kura clover failed to germinate faster than unprimed seed (P>0.05), whereas all but one primed cultivar of birdsfoot trefoil germinated faster than unprimed cultivars (P<0.02).  Primed seed had greater (P<0.001) final percentages at extreme temperatures (5ºC and 40ºC) than unprimed seed.  Generally, priming treatments reduced the shelf life of both legume species as indicated by the accelerated aging test.  Not all seed lots respond favorably to osmotic priming, and therefore individual testing is required of each seed lot to determine the suitability of priming.