You don't need a garden bed to successfully grow root vegetables such as carrots. Planting in containers allows you grow these vegetables even if you don't have the space for a traditional bed. Carrots are well suited to container culture because they do not take up a lot of space, allowing you to plant a lot of carrots in a single pot. There are also no rocks or hard soil clumps in a container garden, so the carrot roots grow straight and do not become damaged.
Fill a container to within 1 inch of the rim with a well-draining potting mix. Use a container that has at least one drainage hole in the bottom. Ohio State University Extension advises using a container that is 10 inches wide and 10 inches deep for carrot crops.
Apply ½ Tbsp. of slow-release, 10-10-10 analysis fertilizer per gallon of soil in the container. Mix the fertilizer in with the soil and then water the soil until the excess moisture just begins to drain out the bottom.
Place the prepared container in an outdoor area that receives full sun. Six to eight hours of sunlight a day is sufficient.
Sow the carrot seeds on the soil surface, spacing them 2 inches apart in rows that are also spaced 2 inches apart. Cover the seeds with ¼ inch of soil.
Mist the soil surface with water when it begins to feel dry. Use a spray bottle or a garden hose attachment that produces a fine mist. Sharp sprays of water may dislodge the carrot seeds.
Water thoroughly after the seeds germinate and sprouts emerge. Water from the top of the container until the excess moisture drains from the bottom. Check the soil moisture daily and water the pot when the top inch of the soil begins to feel dry.
Fertilize the carrots every two weeks with balanced soluble fertilizer, beginning four to six weeks after planting. Follow the label instructions for the exact application rates and method.
Harvest the carrots 50 to 60 days after they began germinating or when the carrot roots are ¾ inch in diameter. Consult the seed packet for exact harvesting dates for the particular carrot variety you are growing in the container.