I absolutely love growing carrots in my home vegetable garden. I set aside a specific 4 x 4 raised bed (a different one each year), just to grow them. With a little sun, water and nutrient rich soil you will soon come to find out just how easy it is to grow your own carrots at home.
First things first. If you want to grow great carrots, that are long, fairly straight and thick, your soil needs to be loose and friable. This soil must also be this condition very deep. Minimum eighteen inches. I say this from experience. If the soil is heavy on the clay, or gets compacted, I have found that my carrots come out short and thick. The carrots still taste great and there is nothing wrong with the carrots, but the carrots are far smaller than I would like.
Carrot seeds, regardless of variety, are small. So when planting them make sure you do not exceed a planting depth of a quarter of an inch. You may be able to get away with a half of an inch, but a quarter is all you will need.
No need to start them indoors. Carrots will do just fine when you directly sow them into your garden. As a side note, your seeds will germinate much better if your soil is a bit warmer and in the pH range of 5.5 to 6.5.
Space out the planting of your carrots about four to six inches to allow, not only for the carrots themselves to grow, but for their roots to expand as well.
Carrots will tolerate light shade, but like all other root crop veggies, full sun will do it wonders. They only need a moderate watering, but be sure to fertilize them every week to 10 days with a good organic mix or compost tea.
Carrots make a great companion plant for tomatoes. In fact there is a wonderful book on the market by Louise Riotte titled Carrots Love Tomatoes: Secrets of Companion Planting for Successful Gardening, which outlines the benefits of planting carrots alongside your tomato plants.
Because carrot seeds are so small, chances are you will invariable plant more than a single area can handle, so be sure to "thin the herd" so to speak by cutting a few of them down to ground level.
You know your carrots will be ready to harvest when you see the carrot tops start poking out of the ground. You can simply judge when they "look" ready.