What are the cultivation methods for open-field chili peppers?

Chili pepper, aliases: horn pepper, long chili pepper, sweet pepper, bell pepper, is an annual or limited-perennial herbaceous plant of the Solanaceae family, genus Capsicum. The original distribution area of this species is from Mexico to Colombia; it is now widely cultivated in countries around the world. In China it is mainly distributed in Sichuan, Guizhou, Hunan, Yunnan, and other places. Below is an introduction to the cultivation methods for open-field chili peppers.

I. Cultivation Methods

The temperature requirements of chili pepper fall between those of yarrow and eggplant. The suitable temperature for seed germination is 23-30°C; below 15°C they cannot germinate. Chili pepper seedlings require relatively high temperatures; when the temperature is low, growth is slow. In the early stage of flowering and fruiting, the suitable daytime temperature is 20-25°C and nighttime 15-20°C. During the fruiting period, if the soil temperature is too high, especially with strong direct sunlight on the ground, it is unfavorable to root growth and easily causes viral disease and sunscald.

1. Land preparation and base fertilizer

Chili pepper is not suitable for continuous cropping, nor can it be continuously cropped with plants of the same family such as eggplant, tomato, potato, and tobacco. The plot for cultivating chili pepper must have good drainage, be convenient for irrigation and drainage, and require deep plowing. It is best to carry out winter plowing and leave the soil fallow to freeze, so as to improve the soil and eliminate overwintering pests and fungal spores. Before planting, prepare the land again; the topsoil should still remain in relatively large clods to allow air circulation and good water drainage, which has a good effect on preventing flower drop, fruit drop, and leaf drop. Changsha vegetable farmers' requirements for chili pepper planting land are “deep furrows and high beds, breaking the old bottom layer; level soil with large clods and smooth water flow.” The bed width is generally 1.3-1.7 m (including furrows), with 2-3 rows planted. There are also wide beds of 2.3-2.7 m with transverse planting on the bed. While making the beds, apply 50-80 loads of decomposed barnyard manure, 15 kg of superphosphate, and 25 kg of plant ash per mu as base fertilizer.

2. Sowing and raising seedlings

Seedbed selection: The seedbed should be chosen on a plot facing south with its back to the north, high and dry with good drainage, convenient water source, and where no Solanaceae crops have been planted.

Seedbed preparation: The seedbed is best deeply dug and the soil heated in the dog days of summer; pour a layer of human and livestock manure on top, and after it dries in the sun, cover with plastic film to prevent loss of nutrients when it rains.

Sowing: Before sowing, thoroughly wet the seedbed soil and break it up fine and level it. The seedbed width is generally preferably 1.5-1.7 m. Generally, seeds are not soaked for germination. Early-maturing varieties are generally sown in January, and late-maturing varieties are generally sown from February to March. To plant one mu, 75-120 g of seed is needed.

After sowing, cover the seeds with fine soil mixed with old chaff ash or coal ash, about 2 cm thick, just enough to cover the seeds. Then water, and after the water is absorbed, cover with plastic mulch. Finally, use thin bamboo poles or bamboo strips to form small arched frames about 0.5 m high, cover with plastic film, and press the north side of the film firmly with soil to help prevent wind damage. It is best to press both sides with bricks so that the film can be lifted at any time for ventilation and air exchange.

Seedbed management: From sowing to emergence, generally no management is needed. Once emergence begins, immediately remove the plastic mulch, otherwise tall spindly seedlings will form. After emergence, uncover the film at 9 a.m. on sunny days and cover it again at 4 p.m. On cloudy and rainy days, ventilate as much as possible. If the seedbed soil turns white and the seedlings wilt, watering is needed; watering must be done from 9 a.m. to 1-2 p.m. Two hours after watering, check again; if some parts still appear dry, replenish water so that the seedlings grow uniformly. Do not water on cloudy, rainy, or freezing days; otherwise, because humidity is too high and the bed temperature drops, disease is likely to occur. On snowy days, add grass mats and cover another layer of plastic film over the grass mats; an electric light can also be installed in the bed to help protect against cold and preserve the seedlings.

Transplanting seedlings: To make the seedlings sturdy with a well-developed root system, when the seedlings produce two true leaves, they need to be temporarily transplanted once, with a plant spacing of 6-10 cm and row spacing of 12-15 cm; water while transplanting to prevent wilting. The preparation, requirements, and management of the transplant bed are similar to those of the sowing bed.

3. Planting

For planting chili pepper, it is preferable that the soil temperature be above 15°C. Planting too early, because the soil temperature is low, results in slow growth and flower drop, failing to achieve the goal of early maturity. For planting distance, early-maturing varieties have a row spacing of 40-50 cm, plant spacing of 26-33 cm, with 1-2 plants per hole; late-maturing varieties have a row spacing of 66-73 cm, plant spacing of 50-60 cm, with 1 plant per hole. Choose a sunny afternoon for planting; on the morning of the same day, the seedbed needs to be watered to make it easier to pull up the seedlings.

4. Field management

Cultivation and weeding: After planting and establishment, carry out one shallow cultivation in time. When the plants begin to grow, carry out one focused cultivation. Before the plants close the rows, carry out one more cultivation. Cultivation should be combined with weeding and earthing up.

Fertilizer and water management: After planting, take advantage of sunny days to apply seedling-promoting fertilizer; each application should not be too large or too concentrated, otherwise it easily causes excessive vegetative growth and delays flowering and fruiting. After the first and second layers of fruit have set, apply more fertilizer to promote fruit enlargement. After the fruit begins to be harvested, the soil must have sufficient fertilizer and water so that the plants can grow and bear fruit normally. If after watering, before the soil dries, heavy rain follows, leaf drop and dead plants will become quite common, especially during the period from the start of the dog days to the beginning of autumn. Therefore, when irrigating, irrigation time must be decided according to the weather forecast. The irrigation depth should preferably not exceed three-fourths of the furrow, and it should be done at night or early morning, with rapid irrigation and rapid drainage.

Harvesting and seed saving: For fresh eating, most are harvested as green fruit, though red fruit can also be harvested. For dried chili peppers, red ripe fruit must be harvested; harvesting should be timely, otherwise it affects plant growth and fruiting.

For seed saving, use the method of combining plant selection with fruit selection, that is, in the field select standard plants according to variety characteristics and tag them as seed-saving plants. Harvest the first layer of fruit early for market, and leave the 2nd-4th layers of fruit as seed fruit. When harvesting the seed fruit after they turn red and ripe, further select fruit with the characteristics of this variety. Spread the harvested seed fruit in a cool place to after-ripen for 5-7 days, then cut open to take out the seeds, dry them, and store them.

II. Planting and Cultivation

1. Seed treatment

Seedling raising is generally from the Spring Equinox to Qingming. Expose the seeds to sunlight for 2 days to promote after-ripening, increase the germination rate, and kill pathogens carried on the seed surface. Or soak in 0.5% trisodium phosphate, or 300-400 times potassium permanganate, or 1% thiourea for 20-30 minutes to kill pathogens carried on the seeds. After repeatedly rinsing off the medicinal solution from the seeds, soak them in 25-30 degree warm water for 8-12 hours.

2. Seedling bed sowing

After the seedbed is prepared, irrigate enough bottom water, then spray with 3000 times Lvheng No. 1 for disinfection. Then scatter a thin layer of fine soil, evenly sprinkle the seeds onto the seedbed, cover with another 0.5-1 cm thick layer of fine soil, and finally cover with a small shed to retain moisture and increase temperature.

3. Seedbed management

After sowing, the daytime temperature is 25-34.7 degrees and the ground temperature is about 20 degrees. Seedlings can emerge in 6-7 days. After 70% of the young seedlings push through the soil, scatter fine soil 0.5 cm thick onto the seedbed while there is no water on the leaf surface, to fill cracks and preserve moisture and prevent the seedling roots from being exposed. The seedbed must have sufficient water supply, but the soil must not be too wet. When chili peppers reach 5 cm in height, the seedbed must be ventilated to harden the seedlings. The ventilation openings should be flexibly controlled according to seedling growth and weather temperature; 10 days before planting, the seedlings can be hardened in the open air. Hardening should be carried out gradually and must not be done all at once. If the seedlings are spindly, spray 500 mL per kg of chlormequat, or 5 mL per kg of mepiquat chloride. If the seedlings are weak and yellow, spray Tianda 2116. Before planting, use Virus Ling or Zhibing Ling and other treatments for root drenching and foliar spraying, which has a relatively good effect on preventing viruses.

4. Land preparation process

Chili pepper has a long growth period and a weak root system. To enable it to flower and fruit continuously, it must have good soil conditions and nutritional conditions. Before planting, plow the land 10-15 cm deep. Apply 5000 kg of barnyard manure per mu, and 15 kg-20 kg of superphosphate can be mixed in. Use short irrigation and short drainage as ditches, with all ditches connected, so that the field does not accumulate water after rain.

5. Planting process

Plant at the appropriate time to promote early rooting. Promoting early seedling growth is the main principle in determining the planting period and management after planting. Chili pepper is also suitable for furrow planting or flat planting. At planting, cover with shallow soil, and gradually earth up to close the rows later. After planting, relying only on drought hardening of the seedlings will damage the root system, so during the seedling stage chili pepper management should use light hardening or no hardening, and promote growth throughout.

6. Planting density

Chili pepper has a compact plant type and is suitable for close planting. Experiments have shown that close planting of chili pepper has great potential for increasing yield, especially for green peppers that continue growing into autumn. Appropriate close planting helps early row closure; because the ground surface is covered and shaded, changes in soil temperature and soil moisture are small, and after heavy rain the root system will not be exposed to the sun, playing a role in promoting roots and seedlings. Generally, the production density of green peppers is 3000-4000 holes per mu (double plants), with row spacing of 50-60 cm and plant spacing of 25-30 cm. Generally, double plants or 3 plants per hole are mostly used. Planting methods include close planting in single rows on large ridges, close planting with alternating large and small ridges, and close planting in double rows on large ridges, all of which can obtain relatively high yields.

III. Management Process

Chili pepper likes warmth, water, and fertilizer, but high temperatures easily cause disease, waterlogging easily kills seedlings, and too much fertilizer easily burns roots. Different stages of the entire growth period have different management requirements. After planting and before harvest, promote roots and seedlings; from the beginning of harvest to the full fruiting period, promote seedlings and push fruit; after entering the high-temperature season, protect roots and seedlings, and prevent decline and death of seedlings; in the late fruiting period, continue to strengthen management to increase yield and income.

1. Management before the start of harvest

During this period, the ground temperature is low and the root system is weak, so there should be more promotion and less control. That is, water lightly and topdress early; cultivate frequently and harden seedlings lightly; water lightly for seedling recovery, and a small amount of manure water can be applied along with topdressing. After watering, cultivate in time to increase temperature and preserve moisture and promote rooting. Hardening should not last too long, about 10 days or so; light watering and light hardening can regulate the relationship between roots and seedlings. After hardening ends, water and topdress in time to increase early yield. Topdressing should mainly be nitrogen fertilizer, combined with some phosphorus and potassium fertilizer, to promote sturdy seedlings and prevent flower drop, and promptly remove the side branches on the main stem below the first flower.

2. Management from the beginning of harvest to the full fruiting period

At this stage, the temperature gradually rises, rainfall gradually increases, and pests and diseases occur one after another. This is the key period determining whether yield will be high or low. To prevent premature aging, the first fruit should be harvested early, watering should be timely, and soil moisture should be maintained regularly to promote seedlings and push fruit, striving to close the rows during the high-temperature season. Upon entering the full fruiting period, before row closure, earth up to protect roots, and combine earthing up with topdressing.

3. Management during the high-temperature season and afterward

The high-temperature rainy season easily induces viral disease, with severe flower and fruit drop, and sometimes a large amount of leaf drop. Therefore, in high-temperature and dry years, irrigation must be done at the beginning of the drought period, not at the end of the drought period, always maintaining soil moisture to inhibit the occurrence and development of viral disease. After rain, apply a small amount of chemical fertilizer to protect the seedlings, and also irrigate in time to prevent drought after the rainy season from forming a peak of viral disease. In the high-temperature season, irrigation should be done in the morning and evening. During the full flowering period, spray 800-1000 times chlormequat 3-4 times, which has a relatively good effect on preserving flowers and increasing yield.

4. Management in the late fruit-shrinking period

After the high-temperature rainy season, the temperature turns cooler, and the green pepper plants return to normal growth. Management must be strengthened to promote the formation of a second full fruiting period and increase late-stage yield. Water in time, and combine watering with topdressing quick-acting fertilizer to supplement the deficiency of soil nutrients.

5. Harvesting

Generally, 2-3 weeks after the flowers fade, when the fruit is fully swollen and green in color, it can be harvested; it can also be picked when the fruit turns yellow or red and ripe. Be careful to harvest in multiple batches as much as possible, picking together with the fruit stalk, and leaving more fruit on the plant, which can increase yield.

IV. Key Points to Note

1. The seedling age of spring chili pepper is about 110 days, and some can reach more than 150 days. In northern regions, planting is usually possible only in mid-April and late May. Chili pepper itself has high and stable yield, but yield reduction in some places is caused by variety degeneration, poor disease resistance, and severe disease. The planting plot should be selected from spring white land where no solanaceous vegetables, cucumber, or yellow tobacco have been planted in recent years. A plot that has just harvested overwintering spinach is also not good. About 7 days before planting, apply 5000 kg of farmyard manure, 75 kg of superphosphate, and 30 kg of ammonium bicarbonate per mu as base fertilizer, open furrows according to 70 cm row spacing, level, form ridges, cover with film, and wait for planting. Planting can be done at 30 cm plant spacing, with the two adjacent rows staggered when setting out seedlings, and one plant per hole. 2500-3000 holes per 667 sq m.

2. From planting to the fruit-bearing period is the early stage of field management for chili pepper; management should promote roots, promote seedlings, and promote plant development. Pay attention to watering and cultivation between times. 15 days after planting, topdress 10 kg of phosphate fertilizer and 5 kg of urea, and combine with cultivation and earthing up to a height of 10-13 cm to protect the root system and prevent lodging. After entering the full fruiting period, the focus of management is to strengthen seedlings and promote fruit. Remove the first fruit in time to prevent fruit drop from causing a decline in growth vigor. Combine watering and fertilizing, topdress 20 kg of phosphate fertilizer and 5 kg of urea per 667 sq m, and earth up around the roots again. Pay attention to drainage and waterlogging prevention. Combine spraying foliar fertilizer and hormones to supplement nutrients and prevent viruses.

3. During the growth period, chili pepper is sensitive to various herbicides, especially 2,4D emulsifiable concentrate; improper spraying of pesticides will cause serious phytotoxicity to chili pepper.