Teri, I have finally figured out how to grow carrots in Texas. If the soil is over 80 degrees, they won't germinate. It can take up to 3 weeks for those tiny seeds to germinate and if they dry out, they die. With our sunshine and ferocious heat, carrots are doomed.
Last fall, I planted a whole packet of seeds and I got less than 10 carrots. I was delirious with joy. I actually grew a carrot! This spring, I went through 3 packets of seeds and got nothing. Nada. I waited until October and planted 2 packets of seeds and have lots of little feathery green sprouts.
I have to tell you, those few carrots we ate last winter/spring were the best tasting carrots I have ever had. So to sum it up, plant in the fall, spray the seed bed every day to keep it moist.