Which month is best for sowing radishes?

As the saying goes, "In the first dog days, plant radishes; in the second dog days, plant vegetables; in the third dog days, plant cabbages." In the north, cabbage and radish are two very commonly grown vegetables. Not only are they widely grown in large-scale agricultural production, but rural families also grow some in their own vegetable gardens. Although many vegetable farmers have many years of experience in growing radishes , they still encounter various problems during the planting process every year, such as small radishes and severe hollow cores. These problems are largely related to the choice of planting time. So when is the best month to sow radishes?

Which month is best for sowing radishes?

According to the planting season of radish, it can be divided into autumn radish and summer-autumn radish:

1. Autumn Radish

It is usually sown in mid-to-late July and can be harvested in mid-September. If the climatic conditions are suitable, autumn radishes will not only have high yields but also high quality.

2. Summer and Autumn Radish

This type of radish is sown between May and June and harvested between July and August. If you plant too early, your radishes may bolt prematurely. Summer and autumn radishes are mainly used to supplement the autumn vegetable supply .

For the cultivation of off-season radishes, according to the characteristics of different varieties, generally sowing begins in April to May in medium altitude areas (800-1200 meters above sea level) and harvesting occurs in June to July. In high-altitude areas, sowing is from May to July, and harvesting is from July to September. Alpine radish cultivation utilizes varieties with strong cold resistance, which can achieve two harvests a year, with the products being available on the market from June until October.

Radish cultivation technology

1. Land preparation and basal fertilizer application

Choosing the right soil is crucial for growing radish. Large varieties of radishes, because their roots go deep into the soil, need to be planted in plots with deep soil and abundant water resources; small and medium-sized varieties are suitable for planting in areas with shallow soil. The soil for planting radishes needs to be deeply plowed and turned over several times in advance, the soil clods broken up and raked flat, and the tillage depth should exceed 26-40 cm. The deep trench and high ridge making method is conducive to drainage. Fertilization should be mainly based on base fertilizer, and special attention should be paid to the combined use of phosphorus fertilizer for better results.

In alpine and semi-alpine areas, the way radishes are grown in summer and autumn varies with the seasons. When sowing in April and May, in areas with an altitude of 800-1200 meters, ground film covering is used for cultivation. Generally, the furrow width is 1 foot and the bed width is 1.2 to 1.4 feet. After trenching, fertilizing and ridge making, cover the soil with mulch quickly when the soil is moist, using 1.8-foot wide corn mulch. In areas with an altitude of 1,300-1,800 meters, the ground film does not need to be covered when sowing in June-August; while in areas with an altitude of less than 700 meters, high temperatures may result in low yields and poor quality when planting radishes in May-July.

2. Planting seeds

The sowing rate of radish is affected by variety, seed quality, germination rate, sowing method and season. Before sowing, the seed quality must be checked. Imported white radish varieties or Nanpanzhou white radish varieties are sown on demand, with 1 or 2 seeds per hole, about 7,600 to 8,000 holes sown per 666.7 square meters (acres), and the seed amount is 90 to 100 grams.

For the field where seeds are to be sown, first drill holes in the rows of plastic film, then plant two rows in one side with a row spacing of 7-8 inches and a plant spacing of 6-7 inches, leaving one plant in one hole. Drill holes half an inch deep, plant the seeds, and cover with nutrient soil so that the ground film is level with the soil. After sowing, use a sprayer to spray a small amount of water evenly to keep the hole surface moist. The open-field planting method without mulch film adopts a 2-2.1 foot area, and other operations are the same as the mulch film covered cultivation.

3. Field management

(1) Time seedlings

Follow the principles of early thinning, staged thinning, and late transplanting. For spot-sown varieties, leave one seedling, and when thinning out, remove seedlings that are diseased or insect-infested, weak, deformed, or have non-original variety characteristics. After transplanting, carefully add soil to prevent the seedlings from bending.

(2) Top dressing and watering

Reasonable application of fertilizer and water and balancing the growth of above-ground and underground parts are the key to obtaining high quality and high yield. In the early stage, it promotes the healthy growth of leaves and absorbing roots, laying a material foundation for the expansion of fleshy roots in the later stage. During the period of rapid expansion of fleshy roots, the leaves are guaranteed to have a longer life and stronger vitality, and more nutrients are produced to ensure the expansion of the flesh.

Radish requires a large amount of fertilizer during its growth. In addition to base fertilizer, topdressing should also be applied according to the condition of the seedlings. In the early stage of taproot growth, apply quick-acting nitrogen fertilizer once and spray biological fertilizer on the leaves 1-2 times. When the fleshy roots begin to swell, that is, after they "break", topdressing should be applied heavily. When the soil is poor or the base fertilizer is insufficient, a small amount of quick-acting nitrogen fertilizer can be applied during the seedling stage, which will have a better effect. Small varieties with a short growth period can use less fertilizer.

Radish has different water requirements at different growth stages. Supply ample water when sowing to ensure rapid germination and uniform emergence. Water the seedlings less for a period of time before they "break out" to help the roots grow deep. During the vigorous growth period of leaves, water appropriately to ensure leaf growth. During the peak growth period of fleshy roots, keep the soil moist to prevent it from alternating between dry and wet. Insufficient water supply affects the expansion of fleshy roots, resulting in an increase in fibrous roots, rough texture, and hollow core. If there is too much moisture in the soil, it should be drained in time to prevent rot. Mulching cultivation is one of the good ways to solve uneven moisture.

(3) Intertillage and weeding

For radishes grown in the open field, after sowing and germination, if rain or watering causes the soil to become compacted, inter-row cultivation and weeding should be carried out in time. For large and medium-sized radishes, inter-cultivation is generally required once from the seedling stage to before row closing to keep the soil loose. Intertillage should be combined with weeding, and in the later stage it should be combined with root protection and soil cultivation. For radishes grown with mulch covering, it is only necessary to remove the weeds between the rows and in the ditches in a timely manner, and no tillage is required.

Radish pest control

1. Disease prevention and control

1. Downy Mildew

Mainly harms leaves. The disease starts from the outer leaves, with small light green to light yellow spots appearing on the leaf surface. As they expand, they turn yellow-brown and become polygonal in shape due to the restriction of the leaf veins. When it is humid, white mold appears on the back of the leaves, and in severe cases, the outer leaves die. For chemical control, spray 600-800 times diluted 72% mancozeb wettable powder , 1000 times diluted 69% anke mancozeb wettable powder, or 600-1000 times diluted 72.2% puriket on the leaves.

2. Black rot

Caused by black rot fungi, the main symptoms are blackening of the center of the root and blackening and rot of the vascular bundles of the fleshy roots, which eventually form cavities. High temperature and heavy rain, excessive irrigation, poor drainage, unrotted fertilizer , continuous cropping, and man-made wounds or insect damage are more conducive to the disease. For chemical control, spray 5000 times diluted 41% Holric suspension, 3000-4000 times diluted 72% agricultural streptomycin or 500 times diluted 50% DT wettable powder at the early stage of the disease, once every 7-10 days, and control continuously for 2-3 times.

3. Viral diseases

The plant is obviously dwarfed, and the leaves are yellow and green or deformed. Aphids are an important vector of transmission. The field management is extensive, the temperature is high and the drought is severe, the occurrence of aphids and flea beetles is large or the plants grow weakly, and the disease is more serious. In the early stage of the disease, you can use 500 times diluted 1.5% plant disease killer or 500 times diluted 20% virus A wettable powder, and spray 2-3 times in a row. To enhance the resistance of the plants, while paying attention to prevent high temperatures and drought.

4. White rust

It mainly harms the leaves; in the early stage of the disease, light yellow spots with unclear edges appear on both sides of the leaves, and later the spots appear as white, slightly raised blisters, about 1-5 mm in size. When mature, the epidermis ruptures and white powdery substances are released, which are the spore sacs of the pathogen. When there are many spots, the diseased leaves turn yellow. The pedicels of the seed plants are infected, the rachis is swollen, and twisted and deformed.

5. Radish heart disease

It mainly harms the fleshy roots of radish underground. It manifests as lesions or even hollows in the center of the fleshy root of the radish, commonly known as hollow heart. Early symptoms are ring-shaped or radiating brown lesions on the fleshy roots, which reduce the commercial value or make them inedible. If hollowing occurs, the value of the goods will be almost completely lost, resulting in greater losses.

2. Pest Control

1. Aphids

When there are 3-5 aphids per plant on average, spray pesticides for prevention and control: 800-1000 times diluted 40% dimethoate or 1000 times diluted imidacloprid can be used for spraying.

2. Pieris rapae

It is the larvae of the cabbage butterfly and mainly damages leaves. The larvae of cabbage looper have a small appetite and poor pesticide resistance before the third instar, so it is best to use pesticides to control the larvae before the third instar. For chemical control, choose 1500 times diluted 10% Diqing suspension, or 1000-1500 times diluted 2.5% Laixi suspension, etc.

3. Yellow-striped flea beetle

Both adults and larvae cause damage. The adult insects bite the leaves, and the larvae damage the roots. The fleshy roots of radish will eventually turn black and rot. For chemical control, use 1000 times diluted 50% phoxim to spray on leaves or irrigate roots.

The above is an introduction to the best sowing time for radishes. Planting radishes is actually not complicated. Just choose the right variety and planting time, and then do the field management work well.