Beetroot is one of the most versatile and rewarding vegetable crops grown in South Africa. Valued for its nutritious roots and edible leaves, it is relatively easy to cultivate and can produce excellent yields under a wide range of conditions. However, successful production begins long before planting. Understanding the crop’s climate requirements, soil preferences and establishment practices lays the foundation for a healthy, productive crop. In this first instalment, we examine the key factors involved in establishing beetroot successfully, from site selection and seedbed preparation to planting methods and mulching.
This popular vegetable is a good choice; it is fairly easy to grow and produces a good yield. Beetroot is a close relative of Swiss chard and sugar beet and has many health benefits. The young leaves are tasty, a good source of vitamin A and can be prepared in the same way as Swiss Chard. The beets are rich in vitamin C.
Beetroot is a cool weather crop, but the hybrid (F1) cultivars available for summer production offer many advantages. The seed is expensive, but these beets are worth growing because they are of a better quality, more adaptable to extreme high temperatures and so are more uniform in shape, produce greater yields and have better internal colour.
Hybrids also taste better, especially out of season.
Climate
Beetroot is usually grown in cool regions or during the cooler seasons in warm areas. The growing period varies from eight to 11 weeks in favourable climatic conditions. In hot weather the quality is adversely affected, which is shown by the alternate white and red rings when the beets are sliced. High-quality beets are characterised by a high sugar content and dark internal colour.
The best planting times for beetroot are spring and autumn, but the vegetables also do well during summer on South Africa’s Highveld and winter in the Lowveld. The optimum temperature for growth is between 15°C and 20°C. Beets are not particularly sensitive to heat, as long as there is enough moisture in the soil. Although tolerant to cold, they grow extremely slowly in winter.
Leaves may be damaged and growth retarded if there is frost before harvesting. Cold weather might delay maturity and the tops tend to be smaller. Direct sowing can result in good germination at temperatures between 6°C and 24ºC.
On hot sunny days, high temperatures that develop at, or just below, the soil surface might injure young plants badly, or kill them. High temperatures for long periods may not only retard growth and depress yield, but could also cause an undesirable strong flavour, concentric rings and a coarse texture.
Soil requirements
Sandy to deep, well-drained sandy loam or silt loam, high in organic matter, is recommended. Cloddy, stony, poor or very shallow soils are not suitable. Uniform soil moisture is essential for good quality. If the soil is compacted or the clay content is very high, roots are likely to be deformed and to develop a tough texture that reduces quality. Crops thrive in deep, rich sandy loam, with a pH of between 6 and 6,5 (but not below).
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Raised beds
Raised beds can increase the effective depth of soil, allowing it to drain better, concentrate topsoil around the root zone, and provide more oxygen for healthy root development. Aeration is better, and disease, infection and the incidence of damping off are all reduced. Raised beds are truly beneficial if soil is heavy and/or poorly drained. Harvesting is also easier. Raised beds should be 1–1,2m wide with 50cm between them. If making them by hand, mark the area with twine, then use a spade and a rake to make the beds.
Large-scale farmers obviously use special equipment to make beds. If you have 1,2m wide beds, six rows or furrows that are 2cm deep would be good spacing. Start the furrows 10cm from the side of the seedbed and allow 20cm between rows. Sow the seed 2–3cm apart and cover the furrows firmly with the soil from the furrows.
Direct sowing
It is essential that farmers buy quality seed that has a good germination percentage. It is very important to establish a fine, level seedbed when sowing the seed and to irrigate lightly a day before sowing. If done by hand, try to sow the seed evenly in the furrow about 3–4cm apart. Do not sow too densely – that makes later thinning of the plants uncomfortable. Thin plants to 5–9cm apart in the rows, depending on the size of beets needed for a specific market. If possible, sow seeds when the weather is cloudy.
Transplanting
More than 90% of beetroot producers sow the seed directly in the soil, but seed can also be sown in seedbeds and transplanted. Seed trays or other containers can also be used to raise seedlings but this is expensive because of the high cost (about 450 000 plants are needed to establish 1ha).
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Mulching
Mulching can protect emerging seed from burning and keep the top soil layer moist and cool. Mulching materials include straw, corn cobs, sawdust, sunflower seeds, peanut shells, grass, grass clippings, newspapers and household waste. Good mulch must be inexpensive, available and easy to handle. It must also be stable, so that it will not easily wash or blow away. Remember that it’s the temperature of the soil, not of the air, that controls seed germination so it is best to wait for soil temperature to rise before sowing seed. In summer, mulch has a cooling effect on the root system. A good layer of mulch can reduce evaporation from the soil surface by as much as 70%.
The success of a beetroot crop is largely determined during the establishment phase. Selecting the right planting season, preparing suitable soil, creating well-structured seedbeds and ensuring proper plant spacing all contribute to strong early growth and uniform root development. In the next instalment, we explore nutrient management, irrigation scheduling, harvesting practices and the major pests and diseases that affect beetroot production.
Source: Agricultural Research Council – Production Guideline for Winter Vegetable Production
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