Climatic Requirements
The carrot is a hardy, cool season crop that can be planted in the garden as soon as the soil can be prepared in the spring. Carrots require relatively large amounts of moisture and are not tolerant of drought. Prolonged hot weather in the later stages of development may not only retard growth but result in an undesirable strong flavor and coarseness in the roots. At the other extreme, prolonged temperatures below 55 degrees F tend to make the roots longer, more slender and paler in color than expected. The best temperature for highest quality roots is between 60 and 70 degrees F.

Carrot plants thrive in deep, loose, well-drained soil. Avoid stony, cloddy or trash-laden soils as they increase the incidence of root defects. Because raised-beds usually have loose soil and receive little compaction from foot traffic, they are an ideal location to grow carrots. Carrots grown on heavy soils may produce considerable leaf growth and forked roots. Carrot plants do not grow well in strongly acid soils; therefore, a pH range of 6.0 to 6.8 should be maintained for best results.

Fertilizers and lime are best applied to soils for carrot production using soil test results as a guide. Arrangements for soil testing can be made through your local Extension office. Carrots require large amounts of plant nutrient elements, particularly potassium, for good production. A fertilizer with the ratio of 1-2-2 such as a 5-10-10 analysis would be appropriate at the time of seeding and again when tops are three to four inches tall and six to eight inches tall. Too much manure and fertilizer applied just before seeding can result in forked roots.

Direct seed carrots into a well-prepared soil early in the spring. Suggested planting depth is 1/4 inch deep in rows spaced 12 to 18 inches or more apart depending on the method of cultivation used. It is important to avoid crusting of the soil around the seed-bed. Covering the seed with vermiculite or fine compost and keeping the soil evenly moist until the seedlings have emerged will help prevent this problem.

After the seedlings have emerged, thin them to one inch apart. When the tops of the carrots grow thicker, thin them to about two to three inches apart. Some seed companies are now offering pelletized seed, making the seeds easier to plant and thin.

After plants are established, applied mulches will help conserve moisture and suppress weed growth. Cultivation, if necessary, should be shallow in order to avoid root injury. Carrots require an evenly-distributed and plentiful soil moisture supply throughout the growing season. However, avoid too much moisture towards the end of the season as this will cause roots to crack.

Watch for the appearance of orange crowns at the soil level as the plants mature. If this occurs, mulch with soil or compost as the sunlight will turn them green. Potential pest problems include leafhoppers, wireworms, carrot rust worm larvae, aster yellow, leaf spot and soft rot. Contact your local Extension office for current control recommendations.

Harvest can begin when carrots are finger size. In general, the smaller carrots are juicier and more tender. You do not have to harvest the entire crop at once. They can remain in the soil until you are ready to use them. Carrots will last until winter in the soil if mulched well. Carrots are best stored at temperatures near freezing in a moist environment.