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Growing capsicums

Capsicum annuum. A warm-season crop grown for its sweet fruit, green at first and ripening red, yellow or orange. It's raised from seed in trays and planted out into warm soil. It wants a long warm season, sun and steady water, and frost kills it. These steps work anywhere: they go by soil and weather, not by month. Also called sweet pepper (UK and Ireland), bell pepper (US and Canada).

How a capsicum grows

1. 
   SowSeeds in a tray, kept warmUp in 10–14 days
2. 
   SeedlingIts own pot at two true leaves3–6 weeks
3. 
   Plant outSame depth, cane beside itAbout 8 weeks from sowing
4. 
   GrowTied in, mulch goes down2–4 weeks after planting
5. 
   FlowerWhite flowers in the leaf joints3–5 weeks after planting
6. 
   Fruit setsGreen fruit swell under the leaves5–9 weeks after planting
7. 
   Pick greenFull size, firm and glossy10–12 weeks after planting
8. 
   Pick ripeLeft on, they turn red and sweeter2–3 weeks later, until it turns cold

Times vary with the variety and the weather. Small-fruited and early kinds crop first; big bell capsicums left to turn red take the longest.

Growing it, step by step

1. Is it right for you?

   • Capsicums need a long, warm season: about three months of warm weather from planting out to the first picking, with days around 21–29°C (70–85°F) and nights around 16–21°C (60–70°F).
   • Frost kills them, and cold nights stall them. Heat is a problem too: on days above about 32°C (90°F), or nights that stay above about 21–24°C (70–75°F), flowers drop and fewer fruit set.
   • The bushes grow up to about 90 cm (3 ft) tall and their stems are brittle, so each needs a cane. Compact kinds grow well in pots at least 30 cm (12 in) across.

2. When to plant

   Sow seeds in trays about eight weeks before you plan to plant out, kept warm: they come up best in soil at 21–27°C (70–80°F). Plant out once the soil is at least 18°C (65°F), the last frost has passed and nights stay above about 12°C (54°F). Put into colder soil, they sit still for weeks.

   Short, cool summers: start seeds early indoors, choose quick or small-fruited kinds, and grow under cover or in the warmest, most sheltered spot. Mild climates: plant out in late spring, once the soil has warmed. Hot or subtropical places: plant as soon as nights are mild, and shade the plants on the hottest afternoons. Where there's no frost, they can crop for a second year. Tropics: they grow most of the year; in the wet season, plant on mounds so the roots drain.

3. Prepare the bed

   • A warm, sunny, sheltered spot with deep, well-drained soil. Dig in plenty of compost a few weeks before planting.
   • Slightly acid to neutral soil suits them, pH 6.0–7.0. See soil pH.
   • Where springs are cool, cover the bed with cloches or plastic for a week or two before planting to warm the soil.
   • Avoid beds that grew capsicum, chilli, tomatoes, potatoes or eggplant in the last three years. They share the same diseases.

4. Sow and plant

   • Sow seeds about 5 mm (¼ in) deep in trays or small pots, kept warm. Once seedlings have two true leaves, move each to its own pot, about 7.5–9 cm (3–3½ in) across, in bright light.
   • If flower buds appear before planting out, pinch them off so the plant builds its roots first.
   • A week or two before planting out, harden seedlings off: put them outside by day and bring them in at night.
   • Plant at the same depth as in the pot, or a little deeper. There's no need to bury the stem as you would a tomato. Space them 45 cm (18 in) apart, in rows 60 cm (24 in) apart.
   • Put a cane in at planting time, so you don't damage the roots later.

5. Get it started

   • Water in well, then water daily for the first week or so until the plants settle.
   • If a cold night is forecast soon after planting, cover them with fleece. In hot sun, shade new plants for the first few days.

6. Keep it growing

   • Tie in: tie the main stem loosely to its cane as it grows. As fruit builds, tie heavy branches to extra canes: the stems are brittle and snap. No pruning is needed.
   • Water: a deep soak at the base about three times a week in warm weather, more often on sandy soil, so the soil stays evenly moist. If it dries out the flowers drop, and uneven watering causes blossom end rot. Pots may need water every day in hot weather.
   • Mulch: about two weeks after planting, once the soil is warm, spread compost or straw at least 5 cm (2 in) deep to hold moisture and keep weeds down. Keep it off the stem.
   • Feed: good soil needs little, but from the first flowers a high-potash liquid feed every two weeks gives a bigger crop; in pots, every week. Too much nitrogen grows leaves instead of capsicums. Stop as the season cools, once new fruit has no time to ripen.
   • Shade: in very hot weather, light shade cloth over the plants on the hottest afternoons helps the flowers set and stops the fruit scalding. Keep the leaves on too: they shade the fruit.

7. Watch for problems

   The common ones, with a Garden help page each where there is one:

   Blossom end rotFlower dropSunscaldAphidsThripsWhiteflySpider mitesFruit flyCaterpillarsGrey mouldAnthracnoseBacterial leaf spotBacterial wiltMosaic virus

8. Harvest

   • Pick green capsicums once they are full size, firm and glossy, about 10–12 weeks after planting out.
   • Or leave them to colour red, yellow or orange, depending on the kind. They get sweeter but take another two to three weeks, and green fruit won't colour once picked. Fruit left on to colour slows new fruit, so pick some green to keep the plant cropping.
   • Cut the stalk with secateurs or a sharp knife. Pulling snaps the brittle branches.
   • Before the first frost, pick every full-sized fruit. Or pull the whole plant and hang it upside down somewhere frost-free, so the last fruit can finish colouring.

9. After harvest

   • Keep them in the fridge's crisper drawer and use them within one to two weeks. Left too long in the cold, the skins pit.
   • Where winters are frost-free, plants can be kept for a second season. Elsewhere, pull them out when they finish. Bin diseased ones rather than composting them.
   • Chillies growing nearby won't make your capsicums hot, but insects cross them, so saved seed can grow hot fruit. To save seed, choose an open-pollinated kind grown well apart from chillies. Seed from F1 hybrids won't grow true.
   • Next in that bed: beans, peas or leafy greens. Keep capsicum, chilli, tomatoes, potatoes and eggplant out for three years.

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Sources

• RHS: How to grow sweet peppers
• University of Minnesota Extension: Growing peppers
• University of Maryland Extension: Growing peppers in a home garden
• Utah State University Extension: How to grow peppers in your garden
• Gardening Australia: Tasty Solanaceae

Facts checked Wednesday 21 October 2026. General guidance only: local advice comes first.