Abstract: Greenhouse experiment was conducted to study the impact of potassium silicate applications by three methods i.e., pre-planting, post planting and foliar spraying accompanied with six times of applying this materials in comparison with oxamyl against Meloidogyne incognita on cucumber plant cv. Hybrid Alpha at 23±5°C. Results indicate that all tested methods and times of adding potassium silicate obviously improved plant growth parameters and reduced nematode criteria as well. Among tested applications, foliar spraying of potassium silicate once on cucumber plant infected with M. incognita after 7 days of its inoculation overwhelmed other methods and times of application in the increment values of plant length (39.8%), total plant fresh weight (141.0%), shoot dry weight (88.6%) and number of leaves/plant (50.0%) respectively and in suppressing nematode parameters since its values were amounted to 0.2 for rate of reproduction, final population density (93.6%), number of galls (81.0%) and egg masses (95.0%) even that of oxamyl values comparing to the check.