Carrots are a root crop and soil temperature is just as important as sunshine. Soil temperature plays an important part for correct growth and square formation. A soil temperature of  65 degrees F or 18 degrees C is ideal. In general, carrots can handle full sun but having the carrots in a portable planter can be ideal for both soil temperature and sun exposure. Pay particular attention to the carrot seedlings in full sun. Carrots can tolerate light shade, but won't do as well.