Due to eventual phase-out of methyl bromide, alternatives for soil sterilization to decrease diseases, pests and specially weeds, have to be found. Field trials were carried out to compare the performance of dazomet (tetrahydro-3,5dimethyl-2H-1,3,5-thiadiazine-2-thione) and metam-sodium (methyldithiocarbamate) in winter; spring and summer on weed control. During winter and spring, application rates tried were: 400, 500 and 600kg ha dazomet, and 167 and 233 kg ha metamsodium. During summer only dazomet were tried at the same rates. Treatments were sealed wither with polythylene sheet on roller sealing. Dazomet and metam-sodium behave almost alike when they were applied in winter for cut flower production. Nevertheless, spring application of dazomet produced better weed control than metam-sodium. Dazomet 600 kg ha was the best tratment when it was applied during summer, independently if it was sealed with polythylene or roller. Weed control varied according to application time. Spectrum was wide in winter, with only trifolium repens escaping. In spring dazomet showed a wider weed control than metam-sodium. Dazomet was more active in spring and winter than in summer. None of the soil fumigants produced phytoxic effects neither to Lilium or Liatris flower production. In a separate winter-field-trial reproduction from sacles of Liliun spp, was carried out with the highest rates of dazomet and metam.sodium. No phytotoxic effects on offsprings emergence were observed.