Carrot roots mature 70 to 100 days after sowing, but you can harvest them as soon as they're large enough to eat. Baby carrots are usually harvested when they're about 3 inches long.
Exposing carrots to low temperatures before or after harvest helps keep them fresh in storage. If your area experiences frosts and frozen soil, harvest carrots for storage after the first hard frost. Alternatively, store harvested carrots in a moist, cool place at 32 degrees Fahrenheit for two to four weeks before storage. You can also leave the carrots in the ground. Spread a layer of straw 8 to 10 inches thick over the carrots to prevent the ground from freezing, and harvest the carrots as needed over winter. Freshly harvested carrots usually taste best.
Harvesting carrots from moist soil reduces the chances of the carrots snapping as you pull them up. If the soil is dry, water it with a garden hose fitted with a spray attachment, until the soil is moist to a depth of about 12 inches, or as deep as the carrot roots.
In most soils, carrots can be harvested by pulling them from the ground. Grab the carrot stems firmly at the base, and pull upward, twisting the root as you pull. In heavy soils, carrots may not pull free from the soil as easily. If you can't pull the carrots up, loosen the soil 1 to 2 inches away from the roots with a garden fork before trying again. Dig up the most stubborn carrots by pushing a garden fork into the soil 1 inch from the base of the stems, and lever the roots up, taking care not to damage the carrots.
Preparing for Storage
Prepare carrots for storage by trimming off the stems and rinsing the roots. Trim the carrot stems to 1/2 inch long with pruning shears. When you've finished, sterilize the pruning shear blades by wiping them with a cloth that was dipped in rubbing alcohol, to help prevent diseases from spreading. You can put trimmed carrot stems in the compost pile.
Rinse the carrots outdoors in a bucket of cold water or with water from a garden hose. Washing carrots in a sink indoors can block your drains with soil. Allow the carrots to air-dry.
Carrots stay fresh for two to four months in cool, moist conditions. You can store them in moist sand or perforated plastic bags.
Moisten clean sand by sprinkling it with water and turning it over with a trowel. Spread 1-inch layer of sand at the bottom of a wooden box, and place a single layer of carrots on the sand. Don't allow the carrots to touch. Cover the carrots with sand, and place another layer of carrots on top. Continue layering until the box is full. Store the boxes of carrots in a cool, moist cellar or pit.
Store carrots in clear plastic bags so it's easy to see signs of rotting. Poke holes 2 to 3 inches apart in the bags. Place the carrots inside, and seal the open ends with twist ties. Place the bags in the refrigerator.
Don't store carrots near apples or pears because these fruits give off gases that make carrots taste bitter.