Growing your own carrots (Daucus carota subspecies sativus) requires using loose, loamy soil in a site or that receives at least six hours of full-sun exposure per day. The plants also need water on a regular basis and a dose of fertilizer midway through the growing season. Soil preparation before planting is one of the most important steps in growing this crop. A thorough turning and preplanting fertilizer and compost will get most beds' soil ready. If your garden has heavy clay soil or otherwise isn't suitable, then use a 12-inch-deep raised bed filled with loamy topsoil; a raised bed makes growing carrots possible anywhere.
Carrots need fast-draining, loose, deep soil to prevent stunted growth and splitting. Using a tiller or garden fork, turn over the garden bed's soil to a depth of 12 inches, breaking up clumps and removing rocks and sticks as you work. Sprinkle granular, 5-10-10 fertilizer -- using 1/2 pound of fertilizer for each 25 square feet of surface area -- and a 2- to 4-inch-thick layer of compost evenly on the bed. Then the soil needs to be turned over to a depth of 12 inches a second time, mixing the fertilizer and compost with the soil.
Planting and Spacing
Carrot seeds germinate in soil that is 40 to 85 degrees Fahrenheit, and they germinate in roughly one week in 75 F, sufficiently moist soil. Sow the seeds directly in the garden bed, spacing them 1/2 inches apart. If you plant multiple rows, space the rows 12 to 24 inches apart. Cover the seeds with 1/2 inch of soil. After planting, it helps to keep the soil moist with daily watering -- soaking the soil at least 1/2 inch deep to moisten the seeds -- until the seedlings start to emerge above the soil surface. The seedlings should appear one to three weeks after the seeds were planted.
Thinning and Weeding
Thinning carrot seedlings gives their roots room to develop. When the carrot seedlings grow 2 inches tall, pull out extra seedlings, leaving 2 to 3 inches of space between the remaining plants. If you grow carrots in rows, leave 12 to 18 inches between rows.
Gently removing weeds growing in the garden by hand at least once each week supports strong growth in carrot plants by minimizing their competition for water and soil nutrients. Avoid using tools that could damage the delicate carrot roots. Removing weeds when they are small reduces the damage and disruption they cause when they are pulled out of the soil.
Keeping the carrot bed consistently moist is critical for a good crop. Letting it dry out then overwatering can cause the roots to split. Soggy soil also damages carrots, causing rot. Carrots' soil needs 1 inch of water per week. During rainy weather, reduce or stop watering. Using a rain gauge will help you determine how much natural rainfall occurs, allowing you to provide supplemental water for the carrots when needed. One inch of water should soak soil to a 5- to 6-inch depth.
Six weeks after carrot seedlings emerge from the soil, or when the seedlings are 6 inches tall, they are ready for a boost of fertilizer. Use a formula high in nitrogen, such as a 21-0-0 or 34-0-0 fertilizer. Sprinkle the fertilizer on the soil down the row of carrot seedlings, placing it to the side of the seedlings and using 1 cup for every 10 feet of row. Water the carrot bed after fertilizing it, soaking the soil to a depth of 5 to 6 inches. Fertilizer that contains weedkiller shouldn't be used, or else your carrots will die.