Garlic (Allium sativum L.) is an important aromatic herbaceous plant belonging to family Alliaceae and one of the most important spice crop grown in the Mediterranean zone of the central part of the country. Crop is exposed to a great seasonal fluctuation of temperature and photoperiod (day length), both having a strong influence on the growth and development of garlic (Pooler and simmon, 1993). The performance of garlic largely depends on the time of planting as the vegetative growth is encouraged under short day and cool temperature. While long day and high temperature is favorable for better bulb development (Subrata et al., 2010). The main phonological stages in the garlic are number of days from planting to emergence, emergence to bulb formation, clove sprouting, leafing, bulb initiation and maturation. Linear relationship has been found between the number of leaves and thermal time above 0℃ under field conditions.

Results and Discussions
Planting dates significantly influenced the various growth and development traits of garlic (Table 1; Figure 1). Plant girth was significantly influenced by different dates of planting in different years. Increase in plant girth was observed with early planting in three years. The beneficial influence on plant girth due to early planting has been reported by Qaryouts & Kasarawi (1995). The number of green leaves per plant and leaf area found significantly maximum with early planting while late planting decreased the quantity of green leaves. This is possibly due to the attained higher vegetative growth, as a result the plants gave maximum number of leaves. Similar results were supported by Das et al (1985) and Rahim et al (1984). The response of different planting dates in different years on root length was very distinct. Early planting continuously increased the root length while late planting decreased the root length. The length and girth of bulb was recorded maximum in three years with the first planting. Rahman and talukdar (Rahman and Talukda, 1986) also observed the same results. Early planting also increased significantly the weight of bulb and yield. Highest bulb weight may be due to receive of sufficient cool and dry weather which possibly increased the vegetative growth and yield of bulb.