The Cool - Season Vegetable Garden: Carrots
By Vincent Lazaneo
Carrots were first grown more than 2,000 years ago. The first cultivated types were probably purple and were selected and grown in middle Asia near Afghanistan around 600 A.D. The yellow carrot, which is a mutation of the purple type, was probably grown in Iran or Syria in the ninth or tenth century. White carrots, which are variations of yellow types, were also grown.
Carrot cultivation spread from Arab countries to Spain and Italy and then to all of Europe by the 14th century. The first orange varieties emerged in Holland in the 17th century; they had a good flavor and their popularity grew. North American settlers brought the orange carrot with them from Europe, and it remains the most popular carrot color in the western part of the world.
Packets of orange-colored carrots are sold in most garden centers; other colors are available from some online seed catalogs: www.kitchengardenseeds.com (‘Purple Dragon’, ‘Atomic Red’, ‘Yellowstone’, ‘Snow White’); www.kitazawaseed.com (‘Atomic Red’, ‘Cosmic Purple’, ‘Kyoto Red’, ‘Lunar White’, ‘Silver Yellow’); www.territorialseed.com (‘Purple Haze’, ‘Rainbow’, Yellowstone’, ‘Red Samurai’, ‘White Satin’).
Carrots can be planted in our area from fall to spring. Dig soil about a foot deep and mix in aged compost and fertilizer high in phosphorus and potassium (e.g. 5-10-10). Rake the surface level and irrigate well to settle the soil. Wait a few days and plant when the surface soil begins to dry. If manure was used for fertilizer, wait about one month before planting.
Plant seed in rows about ¼ inch deep. The seed is very small and should be sown thinly to prevent overcrowding. Carrots germinate slowly (14-21 days) and the seed must be kept moist with frequent light irrigation until it sprouts. To make seed sprout quicker, carefully put boiling water in a thermos and pour a little over the seed in the furrow. Cover the seed with potting soil, then water lightly.
When seedlings emerge, thin them, you can cut off the tops of the weakest, crowded plants with scissors to avoid disturbing roots of the remaining plants. When the tops are about three inches tall, thin again to 1-2 inches apart. Young carrots can be harvested as soon as they are large enough to use.
Common carrot problems include misshapen or forked roots, green “shoulders” and split roots. Forked roots can be caused by hard soil or rocks, overwatering, young roots in contact with fertilizer pellets or fresh manure, overcrowding and root knot nematodes. A young carrot has a root the thickness of a sewing thread and the growing tip will die and then fork when it encounters soil saturated with water (no oxygen).
To grow a long, straight root, stop watering seedling carrots when the tops are ½-3/4 inches tall. This will allow the surface soil to become drier and let the tiny root grow deeper to attain its maximum length. When the tops show a slight wilting, resume normal watering.
As carrots mature, the roots may push above the soil surface and the exposed part will turn green and develop a slightly bitter taste. To prevent green “shoulders,” cover the exposed root with compost or soil.
Mature carrots may split after irrigation if the soil was somewhat dry. To prevent splitting, apply a layer of organic mulch and keep the soil evenly moist.
Vincent Lazaneo Urban Horticulture Advisor for UC Cooperative Extension. He helped found the San Diego County Master Gardener Association more than two decades ago and serves as its advisor. He is the author of numerous articles on plants and pests that appeared in the San Diego Union-Tribune, California Garden and other publications
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