Though full sun is best, carrots can handle some shade as they are a cool weather crop. The most important factor when it comes to growing carrots is making sure that the soil is well-loosened. Use a shovel to loosen the soil in your planting area extremely thoroughly. Remove any rocks or hard, clumpy soil from the area. Use a rake to catch any small stones. You want the soil to be fluffy rather than hard and clay-like. If the soil is too clay-like, you can soften it by adding organic matter (such as yard trimmings or manure), sand, or compost to the soil. If you do not do this, the carrots will not reach a good shape. Mix in about four inches of organic compost into your soil. This will help the seeds germinate in the soil and encourage a hardy production.
Begin to sow the carrot seeds three weeks before the last spring frost. Then gradually sow more seeds once per week for the next two to three weeks after the initial planting. Putting many plantings in will ensure you have lots of carrots to eat during the season. Carrots like a cool climate. If you are planting in USDA hardiness zone eight or warmer, you should sow your carrot seeds in the fall or winter.
You can broadcast your seeds at random or plant in rows. If planting in rows, space the seeds about 1–2 inches apart in a shallow trench, no more than 1⁄2 inch deep. Space each row of carrots 8–10 inches apart from each other.
The seeds will take about one to three weeks to sprout depending on the temperature of the soil. The colder the soil, the longer the seeds take to germinate.
Water the carrots very carefully after planting. The seeds are light and fragile and can easily get washed away if you water too much or too vigorously. Keep the soil moist at all times. If you are in a hot climate, this means watering your carrot plants daily. Just be sure not to wash away the fragile seeds or harm the sprouting seedlings with too much water pressure.
Apply mulch to sprouting seedlings. Add a few inches of a leaf, bark, or hay mulch to the ground around the seedlings to seal in the moisture. Pull out any weeds that develop through the mulch by hand. Do so gently so as not to disturb the carrot roots. Be sure to cover any part of the carrot itself that begins to grow out of the ground with mulch. If the carrot crown is exposed to the air, it will become bitter.
When the tops of the carrots reach two inches high, thin the carrots to one inch apart by pulling the small carrot plants out of the ground. After another two weeks passes and the carrot tops have grown several inches high, thin the plants again to three to four inches apart. Be sure not to skip this step, as crowded carrots will not grow straight and may not develop fully.
The bigger and longer they grow, the sweeter and juicier they become. However, you can pluck and eat them as soon as they grow big enough to eat, which usually takes anywhere from two to three months after planting. You can tell if a carrot is ready to harvest when the crown is sticking slightly out of the ground and the diameter of the carrot is about 3⁄4 inch across.