In order to study the effects of environment and silicon spray on the growth of the vegetative of different rice (Oryza sativa L.) cultivars, a pot experiment was conducted as a randomized complete design with three replications in the greenhouse of deputy of Rice Research Institute of Mazadaran (Amol), Iran. Treatments included the five cultivars of Tarom Mahali, Shiroodi, Fajer, Keshvari and Khousar in two environments (greenhouse and open space) with silicon spray (5% silicon ligules fertilizer) at a mid-tillering stage on one plant per pot. During the maximum tillering stage, plant height, leaf area, leaf, stem, root and total dry weight were measured. The highest dry weight of stem and leaf Tarom Mahali and Fajer cultivars in the greenhouse with the silicon spray were 1.92, 1.81, 1.87 and 1.89 gram per hill, respectively. The greenhouse environment in comparison to open place environment increased 30-70 percent of vegetative growth of rice cultivars in tillering stage. The silicon spray in the open space environment compared to greenhouse did not have a positive effect on the vegetative growth of rice cultivars. The silicon spray was not effective in decreasing low temperature on the rice growth in the autumn. In the open space, Khousar and Tarom Mahali cultivars had better vegetative growth than the other rice cultivars