THE HOW DO GARDENER: Carrots – a complete planting guide



Fresh picked carrots (Photo by Rick Bickling)

Carrots (Daucus carota) have been grown as a food crop for more than 2,000 years. They were brought to the early United States colonies in 1609. They are rich in carotene (a source of vitamin A) and high in sugar.

Carrots are hardy cool-season biennials that are frost tolerant and can be planted as soon as the soil can be worked in the spring. They grow best when nighttime temperatures are around 55 degrees F and daytime temperatures are around 75 degrees F. Temperatures much higher than this will produce discolored, poor quality carrots. In our area, a fall planting can be sown between September 15 and November 15, and a spring planting between January 15 and March 10.

Carrots grow best in sun to partial shade in rich, loose, sandy loam soil that is well drained, and fertile. Before planting carrots, remove all rocks, trash and weeds from the planting area and till the soil to a depth of 8 to 12 inches. Plant carrots to a depth of ½ inch with the seeds spaced at the rate of 3 to 4 seeds per inch. Seeds will take two weeks or more to germinate.

The varieties recommended by the Williamson County office of the Texas AgriLife Extension Service, along with their estimated days to harvest are: Chantenay Red Core – 65, Danvers 126 – 75, Little Finger – 65, Mokum – 54, Nantes – 68, Nelson – 56.

Carrots prefer a soil pH between 5.8 and 7.5. Before planting, apply a 10-10-10 fertilizer, at the rate of 1 cup per 10 feet of row, in the planting area and then mix it into the top 3 to 4 inches of soil. After the seeds sprout, Fertilize your plants once a week with an application of a balanced fertilizer such as Miracle-Gro Vegetable Food.

Once planted, water the carrots regularly to keep the soil evenly moist to a depth of about 3 inches. Water early in the morning to allow plants to dry quickly and reduce the opportunity for disease infection. Drip irrigation is recommended to allow the water to get right to the carrot root.

Keep the garden free from weeds, as weeds will compete with the growing carrots for soil nutrients and water. Do not dig too deep when using a hoe, or pulling weeds to avoid damaging the root.

Carrots that grow too close to each other will be malformed and of poor quality. When the carrot seedlings reach a height of 2 inches, carefully thin the plants so that the remaining plants are 2 inches apart. When they reach a height of 4 inches, thin them again so that the remaining plants are 4 inches apart.

Although fairly hardy, there are several insects that may damage your crop. Cutworms are 3/4” curled caterpillars that, if present, can be found just under soil line. They cut plants off at soil line, chew 1/4’’ holes in pods or seeds, and oc­casionally chew leaves. Apply a Bacillus thuringiensis (Bt) based insecticide to control them. Wireworms are thin, about ½ to 1½ inches long, worms with a dark head and tail that feed on the carrot root. Apply a Bacillus thuringiensis (Bt) based insecticide to control them.

Diseases may be a problem during cool, wet weather. A variety of viruses attack carrots and each produc­es symptoms characteristic of the particular virus species such as leaves mottled with yel­low spots, and knotted or forked roots. Treat with an approved fungicide. Neem oil, sulfur, and other fungicides can be used.

Carrots will be ready to harvest in about 54 to 75 days, when the carrot is about 1 to 1½ inches in diameter. Carefully remove the carrot by reaching into the dirt around the outside of the carrot and gently pulling it out. Carrots planted in the summer may be left in the soil until the first killing frost.

Cut off the green tops off of the carrots 1 inch above the root and wash them. Store carrots in a sealed plastic bag in the refrigerator at 32 degrees F with high humidity where they will stay fresh for several weeks. Carrots may be buried in the sand in an underground root cellar, and under the right storage conditions will keep for four to six months.

If you like carrots, get some seeds now to be ready for a fall planting. You’ll find it nice to know that something new is growing in your garden long after most summer crops have faded.

Rick Bickling is a certified Master Gardener in Williamson County. He has been designing, planting and maintaining landscapes and gardens for more than 30 years. 

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