Carrots (Daucus carota) are a biennial crop grown as an annual for its root. It is a cool season vegetable and tolerates warm temperatures early in the growing season. Roots attain their optimal color when the air temperature is 15°C to 21°C. Root color deepen rapidly when temperatures are within the stated range three weeks before harvest, but color can decline at higher temperatures. The orange color of carrots is due to presence of carotenes, which human metabolism breaks down to vitamin A.