Quinoa is a highly nutritious food product, being cultivated for several thousand years in South America, and it is recently introduced in Morocco and showed a high potential of adaptation in Morocco. A field study was carried out in the south of Morocco in order to investigate the effects of sowing date on quinoa performance in a series of experiments conducted for adaptation of quinoa. The experiment took place in Agadir, with a test of 10 sowing dates, each 15 days from 1st November to 15th March. Sowing dates affected the growth and productivity due to differences in temperature, precipitation and radiation over the year. Highest seed yield and dry matter yield were obtained when quinoa sown in November and early December. The growing season length has been affected by accumulated radiation. In addition to abiotic factors (temperature, radiation, rainfall) affecting quinoa growth, biotic factors such as downy mildew and weeds affected the yield. Early sowing in November to early December secured good plant development when low temperatures occurred in January and February and downy mildew appeared in March.