Capsicum Cultivation: Open Field and Polyhouse Farming Guide

Capsicum, commonly known as Shimla Mirch in India, is a highly profitable vegetable crop with a growing market in urban areas, restaurants, and food processing industries. It is grown for its bell-shaped fruits that come in green, red, and yellow colours. Because of its high price potential, capsicum farming has become a preferred choice for progressive farmers. However, capsicum is a sensitive crop that requires high management skills, proper irrigation, and pest control to achieve good returns.

Farmers can cultivate capsicum in open fields or under protected structures like polyhouses and net houses. While open-field farming is less expensive, polyhouse cultivation allows year-round production, protects the crop from extreme weather, and produces high-quality coloured capsicum which sells at premium prices. This guide covers both methods, helping you understand the details of capsicum cultivation.

Successful capsicum farming requires a systematic approach to nursery management, soil preparation, and irrigation. Because capsicum plants have a long growing season and produce fruits continuously over several months, maintaining plant health and nutrient supply throughout the crop cycle is essential for high yields and long-term profitability.

Open Field vs Polyhouse Cultivation

Before starting, you must decide whether to grow capsicum in the open field or in a polyhouse. Open-field cultivation is suitable for green capsicum. It requires lower capital investment and is easier to set up. However, the crop is exposed to pests like thrips, aphids, and whiteflies, and heavy rains can cause flower drop and fungal diseases.

Polyhouse cultivation, on the other hand, involves growing capsicum in a controlled environment. This setup is highly recommended for red and yellow hybrid capsicum, which are sensitive to direct sunlight and high humidity. In a polyhouse, you can control the temperature, humidity, and light, resulting in a yield that is three to four times higher than open fields. The fruits are larger, uniform, and free from insect damage, ensuring higher market rates.

Coloured capsicums grown in polyhouses also command much higher prices in modern supermarkets and high-end restaurants. Although the initial setup cost of a polyhouse is high, government subsidies through schemes like the National Horticulture Mission make it accessible for many farmers, helping them achieve quick payback on their investment.

Another alternative is shade net house cultivation, which offers a middle ground between open fields and polyhouses. A shade net house reduces light intensity and wind speed, providing a milder microclimate for green capsicums during the hot summer. It requires less investment than a polyhouse while still offering some protection against large insect pests like grasshoppers.

Nursery Raising and Transplanting

Capsicum seeds are expensive, especially hybrid varieties, so sowing them directly in the field is not recommended. Instead, raise the seedlings in a nursery. Using plastic pro-trays (plug trays) with coco peat as a medium is the best modern nursery practice. It ensures healthy roots, high germination, and easy transplanting without root damage.

Sow one seed per cell in the pro-trays, cover them with a thin layer of coco peat, and water them lightly. Keep the trays in a greenhouse or shade net. The seedlings will be ready for transplanting in 30 to 40 days when they have developed 4 to 5 true leaves. Before transplanting, harden the seedlings by gradually exposing them to direct sunlight and reducing water for a few days.

Hardening prepares the young plants to withstand the thermal and physical shock of field conditions. Transplanting should be carried out in the late afternoon when the sun is not too harsh, and the field must be irrigated immediately afterward to help the roots establish in the new soil.

During the nursery phase, paying attention to seedling nutrition is vital. Apply a mild, water-soluble NPK solution to the pro-trays once a week after the first true leaves appear. This nutrition builds strong stems and prepares the seedlings to survive the transplant shock. Avoid transplanting during dry, windy days, as the wind can cause severe moisture loss and wilt the young plants.

Soil and Land Preparation

Capsicum needs well-drained, fertile soil with good aeration. Sandy loam soil with high organic matter is ideal. Avoid heavy clay soils that retain water, as capsicum roots are highly susceptible to collar rot and damping-off. The ideal soil pH is between 6.0 and 6.5. If the soil is alkaline, apply gypsum, and ensure the soil is thoroughly sterilised before planting, especially for polyhouse farming.

Plough the field three to four times to create a fine tilth. Add 10 to 12 tonnes of well-rotted farmyard manure per acre. For both open field and polyhouse cultivation, prepare raised beds. Raised beds should be 90 to 100 centimetres wide, 30 centimetres high, and have a walking path of 45 to 50 centimetres between the beds. Raised beds improve drainage, prevent soil compaction, and make harvesting easier.

Applying neem cake at 200 kilograms per acre during bed preparation is highly beneficial. It controls soil-borne grubs and nematodes while enriching the soil. Covering the raised beds with silver-black plastic mulch is also recommended, as the silver side reflects light to repel thrips, while the black side prevents weed growth.

Sowing Season, Seed Rate, and Spacing

In India, capsicum is transplanted during different seasons depending on the region. For the winter crop, transplanting is done from September to October. For the summer crop, transplanting is done from January to February. In hills, it is transplanted from March to April. In a polyhouse, planting can be done almost year-round, but avoiding peak summer months for transplanting is wise.

The indicative seed rate is about 100 to 150 grams per acre for polyhouse cultivation, where hybrid seeds are used. For open-field cultivation, the seed rate is 200 to 250 grams per acre. Transplant the seedlings on the raised beds in a double-row system. Keep a row-to-row spacing of 60 centimetres and a plant-to-plant spacing of 45 centimetres. Plant in a zig-zag pattern on the bed to ensure each seedling receives enough sunlight and air.

This zig-zag double-row planting system maximises the canopy space, allowing the plants to shade each other slightly. This natural shading protects the developing fruits from direct sun, which can cause sunscald. It also makes installing the trellis and drip lines much cleaner.

Drip Irrigation and Fertigation

Capsicum has a shallow root system and is highly sensitive to both water scarcity and excess water. Therefore, drip irrigation is essential. Install a drip system with a 16 mm lateral line on each bed, with drippers spaced 30 to 40 centimetres apart. Drip irrigation keeps the soil moist at the root zone without saturating the surrounding soil.

Water the crop daily or every alternate day, depending on the weather. A general rule is to keep the soil moist but not wet. Through the drip system, you should also apply water-soluble fertilisers (fertigation). This method delivers nutrients directly to the roots, reducing waste. The fertigation schedule should be split into different stages: vegetative growth, flowering, and fruit development.

In hot summer months, irrigation must be done early in the morning. Watering during hot afternoon hours can heat up the drip lines and stress the plant roots. Using soil moisture sensors can help you plan irrigation precisely, ensuring the plants never experience moisture stress.

Nutrient and Fertiliser Schedule

Capsicum requires balanced chemical and organic fertilisers to support heavy fruit load. An indicative fertiliser recommendation for open-field capsicum is 50 kilograms of nitrogen, 30 kilograms of phosphorus, and 30 kilograms of potassium per acre. Always consult your local Soil Health Card and modify this schedule based on your soil test.

Apply all the phosphorus and potassium, along with one-third of the nitrogen, as a basal dose during bed preparation. The remaining nitrogen should be split and applied in two doses at 30 and 60 days after transplanting. For polyhouse crops, fertigation with water-soluble NPK (like 19:19:19, 12:61:0, and 0:0:50) is carried out twice a week. Calcium and boron sprays are also important to prevent blossom end rot, a common physiological disorder where the fruit bottom turns black.

Magnesium sulphate and zinc sulphate should also be added in small doses, as they support chlorophyll production and fruit skin quality. A balanced micronutrient spray every 15 days keeps the foliage dark green and prevents premature flower drop, ensuring a continuous fruit set.

Training, Pruning, and Support Systems

In polyhouse cultivation, supporting and training the plants is crucial because capsicum plants can grow up to 2 to 3 metres high. Use a trellis system with plastic twine ropes hanging from overhead wires. Tie each plant gently to the twine, wrapping it as the plant grows upward.

Pruning is also required to maintain fruit quality. Allow only 2 to 4 main stems to grow on each plant, and pinch off any side shoots or suckers regularly. This practice ensures that the plant directs its energy toward producing larger fruits rather than excessive leaves. Pruning also improves air circulation, reducing the risk of fungal diseases inside the dense canopy.

For open-field cultivation, short wooden stakes can be placed at regular intervals along the rows to support the plants. Heavy fruit loads can cause the branches to snap, especially during high winds or rain. Proper staking keeps the plants upright and ensures the fruits do not touch the ground.

For the training wires, ensure they are securely anchored to the polyhouse framework. As the capsicum plants grow and produce fruits, the weight on the wires increases significantly. If the wires are loose, the plants will sag, causing the stems to rub against each other and create wounds that are entry points for bacterial pathogens.

Pest and Disease Control

Capsicum is highly susceptible to pests. Thrips and mites are the most destructive pests. Thrips suck sap from the leaves, causing them to curl upward and turn brown. Mites attack the young leaves, causing them to curl downward and become leathery. Control them by setting up blue and yellow sticky traps (15 to 20 traps per acre) and spraying recommended miticides or insecticides as advised by your local KVK.

Common diseases include damping-off, powdery mildew, and bacterial wilt. Damping-off kills young seedlings in the nursery, while powdery mildew causes white patches on leaves. Bacterial wilt causes the plant to wilt suddenly and die. Manage these by maintaining good drainage, avoiding overhead irrigation, using resistant varieties, and applying Trichoderma or copper fungicides under KVK guidance.

Bacterial leaf spot is another threat during the monsoon. It causes dark, water-soaked spots on leaves and fruit. Avoiding field activities when the leaves are wet and applying recommended copper sprays are the standard control measures. Maintaining strict sanitation inside the polyhouse is also key.

Harvesting, Grading, and Yield

Green capsicum is ready for harvest 75 to 90 days after transplanting. If you are growing coloured capsicum (red or yellow), they require an additional 15 to 20 days on the plant to develop their full colour. Harvest the fruits when they are firm, glossy, and have reached their full size. Cut the fruit from the plant with a sharp knife, leaving a short stem attached.

After harvest, sort the capsicum based on size, colour, and shape. Grade them into A, B, and C categories. Pack the graded fruits in ventilated cardboard boxes or plastic crates. Under good management, the average indicative yield is 8 to 12 tonnes per acre in open fields, while polyhouse cultivation can yield 20 to 30 tonnes per acre, offering high economic returns.

During transport, coloured capsicum should be kept cool. The fruits have a high moisture content and can shrivel quickly if exposed to heat. Cold storage facilities or refrigerated vans are often used by commercial farmers to transport coloured capsicum to distant wholesale markets, ensuring they arrive fresh.

It is also important to note that the market demand for capsicum varies by color. Green capsicums have a steady, year-round demand in local markets and are easier to sell in large volumes. Coloured capsicums (red and yellow) are high-value niche products. Establishing direct contacts with hotel buyers or modern retail chains before growing coloured varieties can help secure profitable sales and avoid mandi price fluctuations.

Frequently asked questions

What is the main difference between open field and polyhouse capsicum cultivation?

Open fields are suitable for green capsicum and require less cost, while polyhouses are used for high-yield yellow and red capsicums, protecting them from pests and weather.

How long do capsicum seeds take to grow in the nursery?

Capsicum seedlings are ready for transplanting in 30 to 40 days when they have developed 4 to 5 true leaves.

What is the seed rate for capsicum farming?

The indicative seed rate is 100 to 150 grams per acre for polyhouse farming, and 200 to 250 grams per acre for open fields.

What is the best soil pH for capsicum?

Capsicum grows best in fertile, well-drained sandy loam soil with a pH range of 6.0 to 6.5.

How often should capsicum be irrigated?

Capsicum requires regular moisture. Drip irrigation is recommended, watering daily or every alternate day depending on weather conditions.

Why do my capsicum leaves curl upward?

Leaf curling upward is usually caused by thrips infestation. Yellow and blue sticky traps and KVK-approved sprays help control them.

What causes the bottom of the capsicum fruit to turn black?

This is blossom end rot, a physiological disorder caused by calcium deficiency and irregular watering. Foliar calcium sprays can prevent it.

What is the typical spacing for capsicum plants?

Transplant on raised beds in a double-row zig-zag pattern, keeping 60 cm between rows and 45 cm between plants.

How many stems should be maintained per plant during pruning?

Maintain 2 to 4 healthy main stems per plant and regularly prune all other side shoots to improve fruit size.

When can I harvest the first capsicum crop?

Green capsicum is ready to harvest in 75 to 90 days after transplanting. Coloured varieties take 15 to 20 days longer.

What is the expected yield of capsicum per acre?

Indicative yields are 8 to 12 tonnes per acre in open fields, and 20 to 30 tonnes per acre in controlled polyhouses.

How should capsicum be packed for transport?

Sort and grade the fruits by size and colour, and pack them in ventilated cardboard boxes or crates to prevent bruising.

Can I grow capsicum in heavy clay soil?

No, heavy clay soils retain too much water, which causes collar rot and root diseases. Well-drained sandy loam is best.

What is the benefit of using pro-trays for nursery raising?

Pro-trays prevent root damage during transplanting, save seeds, and ensure uniform, healthy seedling growth.

Is capsicum cultivation profitable in India?

Yes, especially coloured capsicum grown in polyhouses, as they have high demand and command premium prices in urban markets.