Because carrots need cool weather, you must get the seeds into the ground as soon as the soil warms to 50 degrees F. At this temperature the carrot seeds will germinate within 10 days, according to the World Carrot Museum. At higher soil temperatures they may take up to 30 days or longer to sprout. An additional crop can be planted in late summer or early fall in cooler regions of the country.
Till the soil in the planting area to a depth of 8 to 9 inches. Crush any large clumps of soil with the back of the shovel and remove any rocks or other debris.
Add 1 cup of urea fertilizer for every 100 square feet of planting area and mix it to a depth of 8 inches.
Deliver a soil sample to your county cooperative extension office for a pH and nutrient analysis. Carrots will not develop properly in acidic soil.
Add any soil amendments suggested by the soil analysis and mix them to a depth of 8 inches. Rake the planting area smooth.
Plant the carrot seeds 1/4-inch deep in rows 15 inches apart. Water the soil to keep it moist while the seeds germinate.
Add a 2-inch layer of mulch to the soil around the seedlings when they sprout. Keep it 1 inch away from the plants.
Remove weeds as they appear. Weeds will compete with the carrots for water and nutrients.
Thin the carrots when they reach one inch in height. Remove the weaker-looking seedlings until there is 3 inches of space between each carrot.