Okay, here are the results of the carrot/cold frame experiment. (Warning: It is not pretty. You might need to avert your eyes.)
This is "Amarillo," a yellow carrot, so I think the color is right. However, they were small and not especially tasty (they were supposed to be sweet, according to the catalog). I planted in September and harvested in February, so they had plenty of time to get bigger and tastier. They were thinned to 1-1.5 inches apart.
So help me out, carrot people. What happened?
Too little light? Too little water? Soil not fluffy enough with compost? All three?