Growth cabinet studies were conducted on the effect of water potential and interaction of temperature and water potential on germination of Brazil pusley, common ragweed, Florida beggarweed, hairy beggarticks, ivyleaf morningglory, Johnsongrass, prickly sida, redroot pigweed, sicklepod, strangler vine, tall morningglory and yellow nutsedge. Decreasing water potential from 0 to -0.1, -0.2 -0.4 and -0.8 MPa caused 12, 32, 75 and 96% reduction in germination of the test species, 3 WAS. A lower water potential of -0.1 MPa resulted in significant reduction in germination of common ragweed, strangler vine, hairy beggarticks and redroot pigweed. Decreasing water potential further to -0.4 MPa caused 77 to 100% inhibition in germination of all the test species, except Florida beggarweed, yellow nutsedge and tall morningglory. No weed seed could germinate at -1.2 MPa, whereas 28, 9 and 3% seeds of Florida beggarweed, yellow nutsedge and tall morningglory were able to germinate at -0.8 MPa. Water stress of -0.1 and -0.2 MPa delayed the germination of Johnsongrass by one and two weeks, respectively. Germination of tall morningglory, Florida beggarweed, ivyleaf morningglory, sicklepod and prickly sida was faster than Brazil pusley, strangler vine and beggarticks. Water stress of -0.2 MPa reduced the germination of ivyleaf morningglory and prickly sida, whereas tall morningglory, Florida beggarweed and sicklepod required -0.4 MPa osmotic potential to significantly reduce germination. Increasing the temperature from 15 to 20 and 30OC increased germination of weed species from 11 to 22 and 34%, respectively. Increasing water stress from -0.1 to -05 and -1.0 MPa resulted in 37, 6 and 0.3% germination compared to 47% with no water stress. Increasing temperature from 15 to 20 and 30OC resulted in 18, 36 and 56% germination at -0.1 MPa osmotic potential. Lower temperature and water stress was more inhibitory than high temperature and increased water stress to many weeds species. Decreased osmotic potential of -1.0 MPa resulted in complete germination inhibition of all species, except Florida beggarweed (11%). An increase in temperature of 5 or 10OC increased germination of tall morningglory from 10 to 34 and 43% at -0.5 MPa osmotic potential. At -0.5 MPa, Florida beggarweed had no germination at 15 or 20OC compared to 43% at 30OC, which was similar to 20OC and lower water stress (-0.1 MPa).