BACKGROUND Ayurvedic classics have advocated to collect the medicinal plants according to part used and seasons in order to get desired pharmacological action and therapeutic benefits. The logic behind this principle is being validated by recent researches. OBJECTIVE To analyze the influence of lunar cycles on growth of Ashwagandha in Shishira and Greeshma Ritu (winter and summer season). METHODS Fourteen small crops of Ashwagandha of average size 10 cm were collected on October 7, 2013, from institute campus and then replantation was done at Charaka Herbal Garden, Gujarat Ayurved University, Jamnagar in an area of 60 cm × 60 cm (l × b). No fertilizers or pesticides were used. The plants were watered daily and plants were uprooted as per lunar cycles for analysis. Eight samples were collected and observed during Shishira and Greeshma season on Pournima (full moon) and Amavasya (new moon) days. The measurements were taken thrice and average values were taken into consideration for study purpose. The variations in morphological characteristics such as length, breadth, weight, and number of roots and twigs were studied through statistical procedure of principle component analysis, which makes interpretation of all possible related variables. RESULTS Root weight (RW), pith diameter (PD) and internodal distance (ID) were found to be increased on full moon days as compared to new moon days. The maximum RW was observed during Greeshma Aashadha Pournima. CONCLUSIONS The study has shown a definite influence of lunar cycles on the growth of the plant parts assessed by RW, PD, and ID that have found to be increased on full moon days as compared to new moon days.