Radish Cultivation Technique Tutorial: A Detailed Guide to the Latest Growing Methods
The radish is a biennial or annual herbaceous plant of the Brassicaceae family, a root vegetable, also known as laifu and "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 resolve phlegm; the fresh root quenches thirst and aids digestion, the dried root promotes urination and defecation; the leaves treat early-stage dysentery and can help prevent dysentery; the seeds can be used for oil extraction for industrial use as well as for food and medicine.
Soil Selection
When planting radishes, you should choose a preceding crop that consumes little fertilizer, leaves behind plenty of organic matter, and shares no common pests or diseases. Avoid using vegetables of the Brassicaceae family as the preceding crop, otherwise diseases are easily triggered. Radishes adapt widely to sandy loam, but to obtain high yields and high-quality produce, a deep, loose, well-drained and fairly fertile sandy loam is still preferable. Grown in suitable soil, the fleshy root can expand fully, take on a regular shape, and have a smooth skin and attractive color, giving it market appeal.
Deep Plowing of the Plot
Level the soil and apply fertilizer evenly; this promotes an increase in available nutrients and beneficial microorganisms in the soil and loosens it for aeration, which helps the absorbing roots take up nutrients and water, thereby rapidly expanding leaf area and accelerating the swelling of the fleshy root. Apply 75 kg of NPK compound fertilizer per mu as base fertilizer. Then carry out soil disinfection and sterilization and control of underground pests. For the fungicide, choose a 600-fold dilution of 50% carbendazim or an 800-1000-fold dilution of 70% thiophanate-methyl for spraying; for the insecticide, choose an 800-1000-fold dilution of 48% chlorpyrifos emulsifiable concentrate for spraying.
Sowing
The quality of radish seed greatly affects plant growth and yield. To achieve uniform emergence and full, strong seedlings, select seeds carefully, using only plump, sound seeds and discarding shriveled, broken and moldy ones. The sowing rate depends on seed quality, soil type, climate and sowing method. Autumn radishes are mostly sown in hills or drills. The amount of seed used is determined by the desired thinning density; for hill sowing, 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 quickly, so thin them in time to prevent crowding, shading and leggy growth. Thin early, thin in several rounds, and establish the final stand at the right time to ensure uniform, strong seedlings. Generally thin 2-3 times, removing weak, deformed and pest- or disease-damaged seedlings.
Reasonable Watering
Watering is mainly determined by the growth characteristics of the radish, the water requirements at each growth stage, and the climatic conditions and soil conditions. After sowing, if the weather is dry, water immediately once, and water again when emergence begins, keeping the soil surface moist to ensure uniform emergence and reduce the occurrence of viral disease. If there is heavy rain, drain promptly to prevent seedling death.
Scientific Topdressing
Autumn radishes are medium-to-large varieties with a relatively long growing period. On the basis of applying sufficient base fertilizer before sowing, appropriate topdressing should be applied; especially on plots with low soil fertility and insufficient base fertilizer, topdressing can significantly increase yield. Fertilizer should be nitrogen fertilizer diluted in water or dilute manure water. After the radish "breaks its belly," it enters the peak leaf-growth stage, i.e. the rosette stage; to promote leaf area expansion, a quick-acting nitrogen fertilizer should also be applied once; when entering the peak fleshy-root swelling stage, apply a compound fertilizer once as topdressing. This helps the fleshy root swell. Then, 20 days before harvest, spray 0.2% monopotassium phosphate as foliar topdressing once a week for 2 consecutive sprays, which has a good effect on increasing yield and improving fleshy-root quality.
Weeding and Pest Control
During the radish growing period, inter-row cultivation and loosening of the soil are needed several times, especially in the seedling stage, when temperatures are relatively high and there is more rain, so weeds grow quickly and frequent cultivation and weeding are required. In high-ridge cultivation, the soil on the ridges is easily washed away by rain, so hilling should be combined with cultivation. For long, exposed-shoulder varieties of radish, because the root neck is long, thin and weak, it tends to bend and lodge, so in the early growth stage soil should be hilled up to expand the root. This prevents lodging from causing curved radishes later. By the late rosette stage, the leaves have closed over the rows, so cultivation is stopped and weeding is done only 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 plus 50-75 kg of water, or spray a 1000-1200-fold dilution of 57.6% chlorothalonil dry granules, combined with root drenching. To control aphids, spray with a neonicotinoid such as imidacloprid diluted in water.
Timely Harvest
The harvest of autumn radishes depends on the variety and the marketing period. Harvesting too early gives low yield and a hard, tasteless root; harvesting too late exposes the fleshy root to freezing or hollowing, degrading quality and causing hollow heart. When the root diameter has swelled to 8-10 cm and the length is 25-30 cm, harvesting is more appropriate.