The effects of soil incorporation of metham-sodium and finely chopped plant residues of broccoli, cabbage, cauliflower, and grass against Meloidogyne incognito and M. javanica over increasing periods of time and a range of dose rates, with or without plastic covering were studied in growth chamber experiments. The scope of this study was to determine the direct effects of fresh organic amendments and the indirect effects of their volatiles on Meloidogyne spp. and tomato plant growth. Amendments were applied at the rate of 5 or 10 kg/m2. The most effective treatment in maintaining low numbers of nematodes was pre-treatment with volatiles of metham-sodium, which resulted in zero invasion of tomato roots. Application of fresh-chopped broccoli, grass and, in some instances, cauliflower also caused a significant reduction in the population of root-knot nematodes. Nematode reduction caused by broccoli was slightly better than by grass. On the other hand, cabbage incorporation did not suppress Meloidogyne spp. to the same extent, though a 19% reduction was observed, even at the lowest dose rate. Suppression of root-knot nematodes was greater in pots amended and covered with plastic tarp as compared to amended non-covered pots. Increased doses for all treatments were further effective in reducing the populations of root-knot nematodes. The direct effect of soil amendments was greater after 2 weeks, while the indirect effects of volatiles were lessened after 2 and 3 weeks.