Open Field Cultivation of Bell Peppers

Around 23% of the global production of 12 million tons of bell peppers is attributed to China, with Turkey contributing 10% and Nigeria 9%. In Turkey, 60% of the annual production of 1.2 million tons consists of sweet peppers, 28% are chili peppers, 4% are bell peppers, and the remaining 8% includes various peppers suitable for pickling, drying, and making paprika.

Bell peppers are low in calories and rich in vitamins A and C. They are utilized in various forms, including fresh, cooked, canned, pickled, sauced, ketchup, concentrated tomato soups, ready-made soups, sausage, tarhana (a traditional Turkish fermented food), pastrami, children’s food, in olives, frozen foods, and in the production of dried and ground peppers for use in the paint and pharmaceutical industries, among other diverse applications.

Climate Requirements: Pepper’s Affection for Warmth

Bell peppers belong to the category of heat-loving plants. Their optimal growth temperature ranges from 18 to 26 ºC. During the early stages, peppers require higher temperatures, thriving when there is ample soil moisture, sufficient nutrients, and a temperature between 24-26 ºC. The daytime temperature of 21-26 ºC and nighttime temperature of 15-17 ºC are conducive to good development. However, growth is impeded when the daytime temperature exceeds 32-35 ºC and the nighttime temperature drops below 15 ºC. Fruit setting decreases at temperatures exceeding 32 ºC, and flower drops occur between 32-35 ºC. No pollination occurs above 38 ºC. The optimal relative humidity for pepper cultivation is 60-70%.

Soil Requirements: Rich and Well-Drained Soil

Ideal soil for bell peppers is characterized by being rich in organic matter, containing various nutrients, loamy, loamy-sandy, with good water retention capacity, quick heating, deep, permeable, and well-drained. Heavy-clay and excessively water-retaining soils, as well as completely sandy soils, are unsuitable for pepper cultivation. Due to the superficial root system of peppers, high soil moisture is preferred, but excessive watering in poorly-drained heavy soils can adversely affect the plants.

The optimum soil pH for bell peppers is between 5.6-6.8.

Water Requirements: Thirsty Bell Peppers

Bell peppers are known for their high water requirements. Optimal soil moisture is desired to be around 70-80% of field capacity, with relative air humidity between 60-70%. Increased root activity is observed in moist conditions. Growth slows down, stems become woody, fruit setting decreases, and flowers drop when water is insufficient. Prolonged water deprivation results in significant yield loss. Regular and spaced irrigation is crucial, and during the initial flowering period, light irrigation at frequent intervals is recommended.

Seedling Cultivation: Optimal Germination and Robust Seedlings

Seedling cultivation aims for 100% germination rate. Hybrid seeds should have a germination rate of no less than 97%, while standard pepper seeds should not fall below 80%. Seedlings are often grown either by individual farmers or by specialized establishments. The materials used for seedling cultivation should have good aeration and drainage properties, a pH value between 6-7, and be free from diseases, pests, and weed seeds.

Pepper Varieties: Grouped by Shape and Usage

In Turkey, pepper varieties are classified into five groups based on shape and usage:

1. Sweet Peppers
2. Chili Peppers
3. Bell Peppers
4. Peppers Suitable for Industry
5. Small-Fruited, Hot Peppers

Each group caters to different preferences and applications.

Cultural Practices: Planting Seedlings and Irrigation

Planting Seedlings

For planting seedlings, the soil needs to be thoroughly tilled and loosened to a depth of 20-30 cm. If using surface irrigation, it is essential to avoid water contact with the plant root collar, as it can lead to root collar diseases. Drip irrigation is preferred to ensure precise water application. Planting peppers in rows rather than flat areas is recommended. After plowing the field, wooden boards and furrows are created. Boards are 80-120 cm wide, and furrows are 40-60 cm wide. Two to four rows are planted on boards, and either single or double rows are planted on furrows. The spacing between rows is 60-80 cm, and the spacing on the row is 30-50 cm.

Irrigation

The purpose of irrigation is to store the necessary water for plant growth in the root zone, which cannot be naturally supplied. Irrigation should be carried out before soil moisture falls below the field capacity. Drip irrigation is preferred, and if using surface irrigation, it should be done in measured amounts. Chemical fertilizers in a liquid state should be applied to the soil. Excessive watering is not advisable due to the weak root system of peppers, which can lead to nutrient leaching and Phytophthora capsici (root crown rot) disease. Overhead irrigation negatively affects pollination and is not recommended due to dusting and disease concerns. In furrow irrigation, care should be taken to keep the furrow sides short. If using drip irrigation, a lateral pipe for every two rows or for each row is sufficient. Drip emitters can be spaced 40-50 cm apart in sandy soils and 75-90 cm apart in moderately heavy soils.

Fertilization: Optimal Nutrient Supply

A good fertilization practice begins with soil analysis. Based on the results, the required amount of nitrogen (N), phosphorus (P), and potassium (K) should be determined. Phosphorus-rich fertilizers should be applied before bud formation and during flowering, while nitrogen and potassium fertilizers should be applied in 3-4 installments from flowering to the fruiting period. The distribution of fertilizers should be adjusted according to the growth stages. In drip irrigation, phosphorus-rich fertilizers should be applied after planting, evenly balanced fertilizers during the growth period, and potassium-rich fertilizers during the fruiting period. Fertilizers should be applied according to water demand, following the principle of less water, less fertilizer, and more water, more fertilizer. During the last 10 days of harvesting, no fertilizer should be applied, and only water should be given.

Common Diseases in Bell Peppers

Common diseases in bell peppers include root crown rot, mildew, Alternaria, anthracnose, stem rot, powdery mildew, downy mildew, white rot, and fruit rot.

Pests Affecting Bell Peppers

Common pests affecting bell peppers include nematodes, cutworms, aphids, pepper weevils, pepper fruit fly, spider mites, leafhoppers, and thrips.