Detailed Guide to Radish Cultivation Techniques: From Sowing to Harvest

Radish is a biennial or annual herbaceous plant of the Brassicaceae family, a root vegetable, also known as laifu or "earth ginseng." It grows 20-100 cm tall, with a fleshy root that is oblong, spherical or conical. It is cultivated throughout China. There are extremely many radish varieties. The root can be eaten as a vegetable; the seeds, fresh roots, dried roots and leaves are all used medicinally: the seeds aid digestion and dispel phlegm; the fresh root quenches thirst and aids digestion; the dried root promotes urination and bowel movements; the leaves treat early-stage dysentery and can prevent dysentery; the seeds can be used for oil extraction for industrial purposes as well as for food and medicine.

Soil Selection

For planting radishes, crops that consume few nutrients, leave behind much organic matter and are free of the same diseases and pests should be chosen as the previous crop. Cruciferous vegetables must be avoided as the previous crop, otherwise diseases are likely to occur. Radish has broad adaptability to sandy loam, but to obtain high-yield, high-quality produce, a sandy loam with deep, loose, well-drained and relatively fertile soil is still preferable. When cultivated in suitable soil, the fleshy root can fully expand, take on a regular shape, have a smooth, clean skin and an attractive color, and thus be marketable.

Deep Plowing of the Plot

Level the soil and apply fertilizer evenly; only in this way can the available nutrients and beneficial microorganisms in the soil be increased, and the soil be made loose and aerated, which is conducive to the absorption of nutrients and water by the absorbing roots, thereby allowing the leaf area to expand rapidly and the fleshy root to expand faster. Apply 75 kg of NPK compound fertilizer per mu as a base fertilizer. Then carry out soil disinfection and sterilization and control of underground pests. For the fungicide, use a 600-fold dilution of 50% carbendazim or an 800-1000-fold dilution of 70% thiophanate-methyl for spraying; for the insecticide, use an 800-1000-fold dilution of 48% chlorpyrifos emulsifiable concentrate for spraying.

Sowing

The quality of radish seeds has a great influence on the growth and yield of radish plants. To achieve uniform emergence, a complete stand and strong seedlings, the seeds should be carefully selected, using only plump, sound seeds and discarding shriveled, broken and moldy ones. The sowing rate should be determined according to seed quality, soil texture, climate and sowing method. Autumn radishes are mostly sown by dibbling or drilling. The amount of seed used is determined by the desired plant density; for dibbling, the hole spacing is 25-30 cm, with 4-5 seeds per hole, and the seeds should be spread out within the hole to avoid crowding after emergence, which would affect seedling quality.

Field Management

After the seedlings emerge, they grow rapidly, so thinning should be done in time to prevent crowding, shading and excessive elongation. Seedlings should be thinned early, in several rounds, and finalized at the right time to ensure a uniform and strong stand. Generally, thinning is done 2-3 times, removing weak, deformed and pest- or disease-damaged seedlings.

Rational Watering

Watering is mainly determined by the growth characteristics of radish, the water requirements at each growth stage, as well as climatic conditions and soil conditions. After sowing, if the weather is dry, water immediately once; when emergence begins, water again to keep the soil surface moist, ensure uniform emergence and reduce the occurrence of viral diseases. If there is heavy rain, drain promptly to prevent seedling death.

Scientific Topdressing

Autumn radish belongs to the medium- and large-sized radish varieties and has a relatively long growth period. On the basis of applying sufficient base fertilizer before sowing, topdressing should be applied appropriately, especially on plots with low soil fertility and insufficient base fertilizer, where topdressing can significantly increase yield. Fertilization should use nitrogen fertilizer diluted with water or diluted manure water. After the radish "breaks its belly," it enters the peak leaf growth stage, that is, the rosette stage; to promote leaf area expansion, a quick-acting nitrogen fertilizer should also be applied once; when it enters the peak fleshy root expansion stage, a compound fertilizer should be applied as topdressing. This helps the fleshy root expand. And 20 days before harvest, spray 0.2% potassium dihydrogen phosphate once a week for 2 consecutive times as foliar topdressing, which has a good effect on increasing yield and improving fleshy root quality.

Weeding and Pest Control

During the radish growth period, multiple rounds of intertillage and soil loosening are needed, especially at the seedling stage, when the temperature is relatively high, there is more rain, and weeds grow rapidly, so intertillage and weeding must be done frequently. For high-ridge cultivation, the soil on the ridge is easily washed away by rain, so hilling should be combined with intertillage. For long, exposed-root varieties of radish, because the root neck is long, thin and weak, it tends to bend and lodge easily, so soil should be hilled up in the early growth stage to expand the root. This prevents lodging from causing crooked radishes later. By the late rosette stage, when the leaves have closed over the rows, intertillage is stopped, and weeding can only be done by hand pulling.

The main pests and diseases of radish are aphids and soft rot. Per mu, use 10 million units of 12% agricultural streptomycin sulfate wettable powder added to 50-75 kg of water, or spray a 1000-1200-fold dilution of 57.6% chlorothalonil dry granules, while also combining with root drenching. To control aphids, imidacloprid-type products diluted with water can be sprayed.

Timely Harvest

The harvest of autumn radish depends on the variety and the marketing period. Harvesting too early results in low yield and a firm, tasteless root; harvesting too late exposes the fleshy root to freezing or causes hollowing, deteriorating quality and leading to hollow heart. It is more suitable to harvest when the root diameter has expanded to 8-10 cm and the length is 25-30 cm.