Planting: To produce the best crop possible, double-dig your planting area or build up a raised bed. Loose, rock-free soil is the goal. If you have heavy soil, add plenty of mature compost.
Start sowing this cool-weather crop 3 weeks before the last expected frost; plant again every 2 to 3 weeks after that. Most cultivars take 70 to 80 days to mature, so sow your last planting 2 to 3 months before the first expected fall frost. In Zone 8 and warmer, plant carrots in fall or winter.
Rake the soil free of lumps and stones. Broadcast the tiny seeds, or for easier weeding, plant in rows. Put a pinch of about six seeds to the inch. They will take 1 to 3 weeks to sprout (they germinate more slowly in cold soil than in warm), so mix in a few quick-growing radish seeds to mark the rows. Cover with ¼ to ½ inch of screened compost, potting mix, or sand—a little more in warm, dry areas—to make it easier for the delicate seedlings to emerge. Water gently to avoid washing seeds away; keep the soil continuously moist for best germination.