Bell Pepper

Bell peppers are one of the mild, sweet types of Capsicum annuum, the same species as many chili peppers. They’re tender, warm-season plants that need lots of sun and steady warmth to crop well, and they grow very slowly when it’s cool. In cool climates such as the UK they’re usually grown under cover, in a greenhouse, polytunnel or cold frame.

The plants are compact, usually about 2 feet (60 cm) tall and 1 foot (30 cm) wide. Most fruits start green and ripen to red, yellow, orange or another color, getting sweeter as they ripen.

Start seeds indoors. Peppers need a long growing season, so sow indoors 6 to 8 weeks before your last frost date. Sow seeds about ¼ inch (6 mm) deep and keep them warm. Gardening experts suggest 65–70 °F (18–21 °C), while gardening experts aim for a soil temperature of 80–90 °F (27–32 °C) and notes that pepper seeds germinate very slowly in cooler soil. When seedlings have two true leaves, move each into its own small pot.

Wait for warm weather. Plant out only after the last frost, once the soil has warmed. Outdoors, nights should stay above 54 °F (12 °C), and plants need a couple of weeks of hardening off first. In the UK, sweet peppers do best under cover and succeed outdoors only in milder areas or long, hot summers.

Pick the warmest, sunniest spot. Give peppers full sun and well-drained, fertile soil. Space plants about 12–18 inches (30–45 cm) apart, depending on the variety. Gardening experts recommend a soil pH of 6.0–6.5, based on a soil test. Grow peppers, tomatoes, eggplant and potatoes in the same spot no more than once every three years.

Pots work well. Sweet peppers grow well in large pots. Use a container at least 1 foot (30 cm) wide for each plant, or put two or three plants in a standard grow bag. Compact and dwarf varieties are ideal for a sunny patio or balcony.

Water steadily. Keep the soil evenly moist; flower buds may fall off if plants get too dry. Moisture matters most while fruit is setting and growing, so water deeply enough to wet the soil at least 6 inches (15 cm) down and don’t let it dry out between waterings. Pots may need water every day in hot weather, and mulch helps keep moisture even.

Feed moderately. Peppers need only moderate amounts of fertilizer. Too much nitrogen gives big, leafy plants with few flowers and fruit. In pots, feed weekly with a high-potassium liquid fertilizer once flowering starts.

Support the stems. Tie each plant to a sturdy cane. The stems are brittle, so plants with a heavy crop may need extra support.

Mind the temperature. Peppers grow best at 70–85 °F (21–29 °C) by day and 60–70 °F (16–21 °C) at night. Above 86 °F (30 °C) they set less fruit, so ventilate and shade a greenhouse in summer.

Diseases. In home gardens the most troublesome pepper diseases are bacterial wilt and bacterial leaf spot; others include tomato spotted wilt virus, cucumber mosaic virus, Fusarium wilt, southern blight and anthracnose fruit rot. Use certified disease-free seed and transplants, rotate crops, and keep tobacco products away from peppers because tobacco mosaic virus spreads easily from tobacco. Good drainage and a four-year rotation help prevent bacterial spot and Phytophthora.

Pests. Watch for aphids, thrips and caterpillars such as corn earworms and armyworms. Aphids and other sap-sucking pests are a particular problem in greenhouses and dry conditions.

Fruit problems. Blossom end rot shows as dark blotches on the ends of the fruit. It happens when the supply of calcium to the fruit is interrupted, usually by uneven watering, so keep the soil evenly moist but not waterlogged. Sunscald comes from too little leaf cover over the fruit.

Peppers are usually ready about 70 to 85 days after transplanting, or 100 to 120 days from seed. Outdoors in the UK they start fruiting later, usually in August.

You can pick bell peppers green once they’re full size and firm, or leave them on the plant to turn red, yellow or orange; fully colored peppers are sweeter. Leaving fruit to ripen fully slows the plant’s production of new fruit, while picking the first peppers promptly encourages more. Cut the stems instead of pulling the fruit, because the branches break easily.

Keep peppers in the refrigerator. They keep best at 45–50 °F (7–10 °C) with high humidity, for two to three weeks. In a typical home fridge they last about a week; making sure they’re dry and wrapping them in paper towels or a paper bag helps them keep longer.