Sweet Pepper Growing Guide
Sweet peppers, also known as bell peppers or pointed peppers, are a vibrant and attractive crop with colourful, glossy fruits. They are tender plants closely related to chillies that require lots of sun and consistent warmth to crop well. The fruits ripen from mid-summer to early autumn and come in various shapes, sizes, and colours including green, red, orange, yellow, and purple. Plants typically reach about 60cm tall and 30cm wide and grow well in large pots.
This guidance applies to the crop in general. Individual varieties and local conditions can differ.
Planting information
Sow seeds indoors from mid-February to early March for growing under glass, or in late March or early April for growing outdoors. Seeds need 18–21°C for germination, so place them in a heated propagator or on a warm windowsill. Once seedlings appear, maintain a temperature of 16–18°C in bright light and water regularly. When seedlings have two true leaves, pot them individually into 7.5–9cm pots, maintaining a high temperature to encourage growth. Keep young sweet pepper plants indoors in warmth until at least late May. For greenhouse cultivation, plant into final containers in late April (heated greenhouse) or mid-May (unheated greenhouse). For outdoor cultivation, plant in late May/June once overnight temperatures are reliably at least 12°C. Before planting outdoors, harden off plants for a couple of weeks to acclimatise them to outdoor conditions. Choose the warmest, sunniest spot, ideally on a sunny patio or beside a south-facing wall, with temperatures of 15°C or more. Plant at the same level they were previously growing in their pot. For containers, choose one at least 30cm wide and use peat-free multi-purpose compost. When planting in the ground, prepare a spot with well-drained, fertile, moisture-retentive, ideally slightly acidic soil by digging in moderate amounts of well-rotted manure (avoid fresh manure or large quantities). Warm the soil with cloches for a couple of weeks before planting. Space plants 38–45cm apart (compact varieties 30cm apart). Cover young outdoor plants with cloches for wind protection, preferably until the end of June. Add canes to support taller varieties.
Harvesting information
In a greenhouse, sweet peppers can be harvested from mid-summer into autumn. Outdoors, fruiting starts later, usually in August, and finishes earlier as temperatures drop. Pick fruits when they are swollen and glossy. Fruits get sweeter as they ripen from green to their final colour (red, yellow, orange, or purple). Harvest at any preferred stage of maturity and colour, but note that leaving fruits to fully ripen on the plant will hinder further fruit development. Towards the end of the season, cover outdoor plants with fleece or bring potted plants indoors to help remaining fruits ripen.