Cultivation Propagated from seed. Soil should be cultivated deeply but avoid excessive tillage. Seed may be planted from April to mid-July, or up to 3 weeks before last frost, using the standard spacing of 3 cm apart in rows 40 cm apart. Seed should be covered lightly with 0.3-0.6 cm of soil. Germination is slow and irregular.
Carrots require relatively large amounts of well-distributed moisture as rainfall or irrigation.
Fertilization procedures should be designed to suit soil. Mineral soils should be supplied with liberal amounts of organic matter. Carrots may be rotated with alfalfa or other legume cover crops, small grains, onions, spinach, or corn, but avoid rotation with celery, parsley, beets, sesbania, as they increase the soil disease problem. When grown for seed, different varieties must be widely separated, because, as a good nectar supplier, they attract many types of insects. For seed production, plants are treated as biennials.