Carrot Seeds Early NantesOverview Carrot requires a relatively long growing season than the other root crops. The optimum temperature is 7. 2 to 23. 9C for germination and 18. 3 to 23. 9C for growth. The best root color develops at 15 20C. Temperature higher than 30C, particularly in later stages of development, induces undesirable strong flavor and coarseness in the roots Variety Details Scarlet red color roots Soft inner core Cylindrical shape with blunt end Average length: