Whether you’re growing carrots for your family’s table or the fresh market, success begins long before the first seedlings emerge. From selecting the right cultivar to preparing the land and sowing correctly, every step lays the foundation for a high-quality crop. In the first instalment of this two-part series, we look at the essential practices that help growers establish a healthy, productive carrot crop.
Carrots are important root crops in commercial and home gardens in South Africa. Here are some pointers for cultivating them. Carrots (Daucus carota) are members of the Apaceae family and are grown for the edible root, which can be eaten raw or cooked. They are rich in carotene (vitamin A). Carrots grow well in cool conditions, as long as there is enough moisture, and they are fairly resistant to cold and frost.
The soil
Carrots need deep, well-drained sandy loam to sandy soil, and the texture is important because it affects how smooth and well-shaped the roots will be. Avoid heavy, compact soil, which will discourage growth. Soil high in fresh organic matter can result in hairy, forked and malformed roots, and stony soil can also produce poor root shapes. The optimum pH is between 6,0 and 6,5.
Also read: How to grow top-quality carrots (Part 2): From irrigation to harvest and storage
Temperature
Carrots are cool-weather plants, but growth slows down if the temperature drops below 10ºC. Although the plants are not particularly sensitive to frost, a severe frosty spell can damage the leaves. The roots can be damaged if the soil temperature drops below 0°C, especially if the plants were irrigated the preceding afternoon.
The temperature and soil moisture influence the colour, shape and quality of carrots. Growth is optimal at 18–23°C, although some cultivars can withstand a great deal of heat. High temperatures (above 29°C) can cause poor colour and thicker centres.
Crop rotation
Rotating crops helps to improve the quality of the soil and keep down soil-borne pests. Carrots make good crop rotation partners for cabbage, lettuce, pumpkin and tomatoes. Leguminous crops such as peas and beans can improve the soil’s nutrient levels.
Also read: Growing beetroot successfully | Establishing a high-yielding crop
Preparing the soil
Loosen the soil thoroughly by ploughing (or using a fork, hand hoe or spade) to a depth of 300–400 mm to allow for good root aeration, root penetration and drainage. Crush all clods with a rake or cultivator.
Remove stones, because they can cause poorly shaped carrots. Even consider building a raised bed.
Remove all weeds before sowing, because carrot seedlings are very fine and cannot compete with weeds.
Also read: Cultivating onions | From soil requirements to transplanting
Spacing
Allow 25–35 cm between rows. Thin out at one to two weeks after emergence, when the carrot seedlings are about 4 cm tall, and again one to two weeks later. This should result in a spacing of 4–5 cm within the row (80–120 roots/ m2). Do not thin out later than four weeks after emergence.
If the crop is not thinned out, the carrots will be small and malformed. Thinning should take place in the afternoon, and when soil is moist.
Applying fertiliser
Apply about 1 000 kg/ha (100 g/m2) of a fertiliser mixture such as 2:3:4 (30)+Zn or 1 100 kg/ha (110 g/ m2) of 2:3:2 (22)+Zn just before planting, and work it into the top 10 cm of soil.
Apply a top dressing of 10 g LAN per metre of row at three weeks and again at six weeks after emergence. Sprinkle on both sides of the row, 2–10 cm from the plants (do not sprinkle on the plants). It would be a good idea to remove all the weeds before applying LAN to avoid their competing with the carrots for fertiliser. Work it into the top 2 cm of the soil using a flat-tined fork. Water well.
In areas known to have a boron deficiency, apply 10–20 kg/ha borax after planting. Do not use manure and compost for carrots, because they can cause malformation of the roots and decrease the marketable yield. If manure needs to be dug in, do so with the crop preceding carrots.
Also read: Growing beetroot successfully | Fertilisation, irrigation and crop protection
Cultivar list
Kuroda offers an excellent yield and has a good shape. It’s 11–15 cm long and has a thin kernel. It can be produced in warmer seasons.
Cape Market is cylindrical, 12–17 cm long and produced in warmer seasons.
Scarlet Nantes, Flacoro, Fancy and Duke are good choices for autumn planting, and Ideal Red and Javelin are good spring cultivars.
Also read: Cultivating onions | Fertilisation, harvesting and crop protection
How to sow
For a small plot, allow 1 teaspoon of seed per 2 metres of row.
Rake the soil surface before sowing the small carrot seeds directly in the soil – carrots cannot be transplanted – and create shallow furrows, about 1,5 cm deep.
Put the seeds in the palm of one hand, take a substantial pinch with the other hand and rub between finger and thumb as you move your hand forwards and backwards along a furrow. Another method is to mix one teaspoon of seed with 10 teaspoons of fine, dry sand and then sow it.
After sowing, cover the seed with fine soil to ensure better germination. In the warmer months, mulch the rows with dry grass to keep the soil cool and moist, as this will assist germination. Remove the mulch after the seedlings have emerged. (If it is kept on too long, the seedlings will become leggy and the sun will burn them easily.)
Emergence may take 7 to 14 days depending on the cultivar, the weather, soil type and season.
Recommended sowing times
The following sowing times are recommended for different regions:
- Limpopo and Lowveld: February to April and July to August
- Highveld: August to mid-March
- Free State and Northern Cape: August to October and late January to March
- KwaZulu-Natal: August to April
- Eastern Cape: July to April, but avoid sowing during midsummer in very hot regions
- Western Cape: August to late March
- Very hot regions: August to September and February to March
- Very cold regions: August to April
- Temperate regions: August to mid-April
This information was first published in the Agricultural Research Council’s “Production Guideline for Winter Vegetables”.
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