Overview
What peppers need, when they crop, and whether they suit your garden.
Every bell pepper starts green, and a red, yellow or orange one is simply the same fruit left to ripen, a few weeks longer and noticeably sweeter. Peppers need a long, warm season: sown in late winter, kept warm, and planted out only when nights are mild. Temperature decides the crop more than anything, so in cool summers the best peppers come from a greenhouse or a sunny wall.
Quick facts
- Botanical name
- Capsicum annuum
- Soil pH
- 6.5 – 7.0
- Feeding
- Moderate feeder
- Temperature
- 21 – 29 °C
- Hardiness
- Any zone, as an annual
- Time to harvest
- 70 – 100 days
- Height
- Up to 120 cm (47 in)
- Propagation
- Seed
Optimal growth
Keep above 12 °C
Growing details
- Spacing
- 45 cm (18 in)
- Sowing depth
- 6 mm (¼ in)
- Frost sensitivity
- Frost tender
Growing calendar
- Start indoors: February, March
- Transplant: May, June
- Harvest: July, August, September, October
Six to ten weeks before planting out (Iowa State, UMN, UMD). Once nights stay above 10 to 12 °C (50 to 54 °F); earlier into a heated greenhouse. Under glass from midsummer; outdoors from August until the first cold nights.
Is this plant right for you?
- Container friendly
- Greenhouse friendly
- Grow bags
- Needs warmth
- Long season
- Needs support
- Frost tender
- Self-pollinating
Good to know
Plan for support early: this plant needs a stake, cage or frame once it gets going. Keep it above 12 °C (54 °F): frost kills it.
Before You Grow
Choose a variety for your season, then find the warmest, sunniest, most sheltered place you have.
Smaller-fruited varieties cope better with cool and hot spells than big bells.
What you need
Seed, or young plants
Seed gives the widest choice. Bought plants should be sturdy, up to 30 cm (1 ft) tall, with stems about as thick as a pencil and no leaf spots.
Warmth for sowing
A heated propagator or heat mat and a bright windowsill or grow light. See growing from seed.
A warm place to grow them
A greenhouse, polytunnel or a sunny, sheltered patio. See where they grow best.
Large pots or growing bags
At least 30 cm (1 ft) wide. See peppers in containers.
Short stakes or canes
Laden stems snap. See support and pinching.
High-potash liquid feed
Such as tomato feed, from flowering. See feeding.
Choose your peppers
Sweet peppers come blocky or long, large or small, and ripen from green to red, yellow, orange or purple. A green pepper is simply unripe.
For short or cool summers, choose smaller-fruited varieties. Big fruit takes longer to grow and ripen, and UMN finds smaller-fruited peppers cope better with both cool and hot spells. Look for descriptions such as ‘widely adapted’ or ‘cold tolerant’, and check the days to maturity.
For pots, dwarf or compact varieties suit a sunny patio, balcony or even a windowsill.
Pointed peppers are generally sweeter and thinner-skinned than bells (RHS).
Disease resistance. If you have had pepper diseases before, choose a variety with resistance codes on the packet.
Grafted plants are more vigorous and crop more reliably in cooler conditions, at a higher price.
Sweet pepper types compared
-
Bell
- Fruit
- Large, blocky, three or four lobes
- Notes
- Picked green or left to colour; large fruit takes longer
-
Pointed
- Fruit
- Long, tapering
- Notes
- Sweeter, with thinner skin than bells
-
Sweet banana
- Fruit
- Long, tapering, pale yellow
- Notes
- Picked yellow or ripened
-
Sweet cherry
- Fruit
- Small, round
- Notes
- Compact; good in pots
-
Italian frying
- Fruit
- Long, thin-walled
- Notes
- For frying and roasting
-
Compact or dwarf
- Fruit
- Small to medium bells
- Notes
- For pots, patios and windowsills
In a short season, smaller fruit ripens sooner and more reliably than big bells.
Where peppers grow best
Peppers are tender and need a long, warm season. They grow slowly in cool spells, and frost kills them.
Temperature. They grow best with days around 21 to 29 °C (70 to 85 °F) and nights above 15 °C (59 °F). They cope with nights down to 12 °C (54 °F) (RHS), but grow slowly. Heat is a problem too: see flowers and fruit set.
Under cover. In cool climates they crop best in a greenhouse, polytunnel, conservatory or cold frame. Ventilate and shade in summer, and damp down the floor on hot days to raise the humidity.
Outdoors, grow them only in mild areas or warm summers, in the warmest, sunniest, most sheltered spot, ideally a sunny patio or beside a south-facing wall. Expect fewer fruits than under glass, and cover plants with cloches until the end of June.
Rotation. UMN plants where tomatoes, potatoes, peppers, aubergines and tomatillos haven’t grown for three or four years.
Sun. Full sun: at least six hours of direct sun a day, and eight to ten is better (UMD). Fruit ripened in warm, sunny weather tastes best; fruit that matures under cool or cloudy conditions is less tasty.
In very hot climates, UMD plants peppers where they get some late-afternoon shade.
Seedlings need strong light directly overhead, or they stretch and lean.
- Best days
- 21 to 29 °C (70 to 85 °F)
- Nights
- Above 15 °C (59 °F) ideally; 12 °C (54 °F) minimum
- Frost
- Kills them
Soil
Peppers want well-drained, fertile soil that holds moisture. On poor or heavy soil, dig in a few bucketfuls of compost or well-rotted manure before planting; never fresh manure.
Warm it first. Cold soil stalls them. Cover the bed with cloches for a couple of weeks before planting, or lay black plastic mulch, which warms the soil, keeps moisture in and stops weeds. UMD waits until the soil reaches 18 °C (65 °F).
Fertility. Test if you can. Many soils already have enough phosphorus; too much nitrogen gives leafy plants that are slow to fruit.
Planting
Sow early in warmth, pot on, and plant out only once nights stay mild.
Don’t rush: plants set out into cold soil just sit there.
When to sow and plant peppers
Peppers need a long season, so they are sown indoors early, earlier than tomatoes.
Sow indoors six to ten weeks before you plan to plant out: Iowa State says six to eight, UMN about eight, UMD eight to ten, some varieties twelve. In the UK, the RHS sows from mid-February to early March for a greenhouse crop, and in late March or early April for plants going outdoors.
Plant under cover in late April in a heated greenhouse, or mid-May in an unheated one.
Plant outdoors after your last frost, once nights stay above 10 °C (50 °F) (UMN), or 12 °C (54 °F) (RHS): late May or June in the UK, mid-May in central Iowa. Cornell plants around the end of May in upstate New York.
- Sow indoors 6 to 10 weeks before planting out.
- Under glass from late April or mid-May.
- Outdoors once nights stay above 10 to 12 °C (50 to 54 °F).
How to grow peppers from seed
Pepper seed needs real warmth to germinate, then bright light and warmth to grow on.
-
Fill pots or trays
With seed compost or a sterile, soilless mix, to 1 cm below the rim, firmed lightly.
-
Sow about 6 mm (¼ in) deep
Four or five seeds to a pot, well spaced, covered with a thin layer of compost or vermiculite. Label them.
-
Keep them warm
The sources differ: the RHS germinates peppers at 18 to 21 °C (65 to 70 °F); UMN keeps a heat mat at 27 to 32 °C (80 to 90 °F), with 21 °C (70 °F) compost ideal. Warm beats cool. Check the compost often, as heat mats dry it quickly.
-
Give seedlings bright light
At 16 to 18 °C (60 to 64 °F), with light directly overhead so the stems don’t stretch.
-
Pot on at two true leaves
Into 7.5 to 9 cm (3 to 3½ in) pots, handling seedlings by a leaf. Keep them warm.
-
Keep potting on
Into slightly larger pots as each fills with roots, until they are ready for their final 30 cm (1 ft) pot or the ground.
-
Pinch early flower buds
UMN pinches off flower clusters that appear indoors, until just before planting out.
How to plant out peppers
Into a greenhouse, a large pot, or a warm, sheltered bed.
-
Harden off over one to two weeks
Start in a sheltered spot with a couple of hours of sun, gradually giving more. Bring them in if nights drop below 13 °C (55 °F).
-
Water the plants less first
UMN cuts back watering a little when plants are 10 to 13 cm (4 to 5 in) tall, to toughen them.
-
Plant at the same depth
Without disturbing the roots. Bury peat pots completely: an exposed rim wicks water away.
-
Space them
38 to 45 cm (15 to 18 in) apart (RHS), compact varieties 30 cm (1 ft); rows 75 to 90 cm (30 to 36 in) apart (UMN). Staggered double rows shade the fruit against sunscald.
-
Add a stake
A cane for taller varieties now, before the crop gets heavy. See support and pinching.
-
Water in and feed
Iowa State gives each plant a cup or two of starter fertiliser solution.
-
Protect outdoor plants
Cloches against wind and cold; in the UK, ideally until the end of June (RHS).
Care
Steady water, a weekly feed once flowering starts, and a stake before the crop gets heavy.
Keep the soil evenly moist: dry spells drop flowers and cause blossom-end rot.
Care by growth stage
Seedling
Temperature: 16 to 18 °C (60 to 64 °F) or more · Pot on: as roots fill the pot
Warmth and strong light. See growing from seed.
Young plant
Stake: at planting · Protect: cloches outdoors
Harden off and plant out once nights are mild. See how to plant out.
Flowering
Feed: weekly from first flowers · Water: evenly
Temperature and moisture decide fruit set. See flowers and fruit set.
Fruiting
Water: daily for pots in hot weather · Support: laden branches
Demand for water and food peaks. See watering.
End of season
Pick: before the first frost
Fleece outdoor plants or bring pots in to finish ripening. See harvesting.
Watering peppers
Keep the soil evenly moist. Dry spells make flower buds fall, fruit stay small, and bring on blossom-end rot.
How much. About 2.5 cm (1 in) of water a week, rain included. In dry weather, soak the soil thoroughly once a week, more often on sandy soil. A light sprinkle that only wets the surface encourages shallow roots.
How. At the base: drip lines or soaker hoses are ideal. Wet leaves invite disease, and splashed soil carries spores.
In pots, check daily: they dry out fast in summer and may need water every day.
Mulch in-ground plants thickly with organic matter, or use black plastic, to hold the moisture.
Feeding peppers
Before planting, dig in compost; without a soil test, Iowa State works in a general fertiliser.
At planting, a starter fertiliser solution helps transplants settle.
From flowering, feed plants in containers weekly with a high-potassium liquid feed such as tomato feed (RHS, Gardeners’ World). Plants in rich soil may not need it, but it can raise the yield. UMD side-dresses after the first fruits set.
Hold back the nitrogen: too much gives bushy, leafy plants that are slow to fruit, and adds to blossom-end rot.
Support and pinching
Support. Pepper stems are brittle and snap under a heavy crop. Put a cane or short stake beside each plant while it is young. Cornell doesn’t tie it: the plant simply leans on the stake. For a row, run a string between stakes set every 2.4 m (8 ft). Push extra canes around a heavily laden plant and tie in the fruiting side shoots.
Pinching the tip isn’t needed for a good crop. Done when the plant is about 30 cm (1 ft) tall, it gives more, smaller fruit, but delays fruiting (RHS).
Early flowers and fruit. See how to plant out: sources differ on whether to pinch them.
Flowers and fruit set
Pepper flowers are largely self-fertile, so fruit set depends on temperature and water more than on insects.
Too cool. Iowa State finds bell pepper flowers drop when nights fall below 16 °C (60 °F).
Too hot. Flowers also drop in heat: above 29 °C (85 °F) by day (Iowa State), or above 32 °C (90 °F) by day with nights above 24 °C (75 °F) (Cornell). The RHS finds temperatures over 30 °C (86 °F) reduce fruiting. Best fruit set is at about 21 to 27 °C (70 to 80 °F). Hot peppers set better in heat than bells.
What helps. Ventilate and shade a greenhouse in summer, damp down, and keep the soil moist. In dry conditions, Gardeners’ World mists the flowers with tepid water to improve fruit set. Outdoors in a heatwave, UMD cools plants with a water spray.
Peppers in containers
Peppers grow well in pots, which also let you give them the warmest spot you have.
Size. One plant in a pot at least 30 cm (1 ft) wide (RHS, Gardeners’ World), about 19 L (5 gal) at least (UMD), or two or three to a standard growing bag.
Compost. Peat-free multi-purpose.
Care. A cane for stability, water daily in hot weather, and a weekly high-potash feed from flowering. See feeding.
Growing peppers indoors
Compact varieties can crop on a sunny windowsill or in a conservatory, where it’s warm enough.
Light. The brightest, sunniest window you have.
Humidity. Mist the flowers in dry indoor air to help them set.
End of season. Outdoor pots brought indoors in early autumn ripen their last fruits.
Problems
Most pepper trouble comes from temperature and uneven watering: dropped flowers, blossom-end rot, sunscald.
Common pepper problems
These are growing problems, not pests or diseases.
Flowers dropping without fruit
- Heat
- Cold nights
- Dry soil
Temperature, most often, then drought. See flowers and fruit set.
Sunken, leathery patch at the fruit’s base
- Blossom-end rot
Calcium doesn’t reach the fruit when soil moisture swings; heavy nitrogen and damaged roots add to it. Water evenly and mulch.
White, papery patch on the sunny side
- Sunscald
Fruit exposed to hot sun with too few leaves to shade it. Keep leaf diseases down, feed lightly for leafy growth, and cut fruit rather than pulling branches off.
Slow growth early in the season
- Cold
- Overgrown transplants
Cool conditions, or overgrown, stressed transplants. Warm the soil and don’t plant too early.
Fruit slow to colour
- Short season
Bells take two to three weeks longer to colour after reaching full size green. In a short season, pick green or grow smaller-fruited types.
More problems with bell peppers
Common pests
Aphids
Colonies build up in large numbers: look for curled, discoloured and sticky leaves (UMN). Check shoot tips and leaf undersides.
Glasshouse red spider mite
Mottled leaves and early leaf fall, mainly under glass (RHS). Damping down keeps greenhouse air humid (RHS).
More problems with bell peppers
Common diseases
Bacterial spot
Small, yellow-green leaf spots with water-soaked edges that merge, turn brown and drop out. Favoured by warm, humid weather and spread by rain and overhead watering. Water at the base and rotate beds.
Viruses
Twisted or patterned leaves and bumpy, distorted fruit. Viruses can’t be cured: remove affected plants (UMN).
More problems with bell peppers
Harvest & Use
Cut peppers green or coloured, never pull them, and keep them cool but not cold.
Harvesting peppers
Pick when the fruit is full size, firm and glossy: green, or left to colour.
Green or coloured. Bells reach mature green 70 to 80 days after transplanting and need another two to three weeks to colour (UMD). Coloured fruit is sweeter and richer in vitamins A and C, but leaving fruit to colour slows the next ones. Peppers don’t ripen further once picked.
How. Cut the stalk with secateurs or scissors. Pulling often breaks off whole branches, taking small fruit with it and exposing the rest to sunscald.
When. Under glass from midsummer into autumn; outdoors usually from August until early autumn. Picking regularly keeps the plant flowering.
End of season. Cover outdoor plants with fleece or bring pots indoors to ripen the last fruits. Before a killing frost, UMD pulls whole plants and hangs them upside down somewhere warmer, such as a garage.
- Full size, firm and glossy: green or coloured.
- Cut, don’t pull.
- Pick often to keep the plant cropping.
Storing and using peppers
Cool, not cold. Peppers keep best at 7 to 10 °C (45 to 50 °F) and high humidity: two to three weeks. In the fridge, a week or more; kept too cold for too long, their skins pit.
Freezing and drying. Peppers freeze well and can be dried or pickled.
Handling. Even sweet peppers can hold a little capsaicin; if your skin is sensitive, wear gloves when preparing lots of them.
Propagation
Save seed from open-pollinated varieties, grown well away from other peppers.
Saving pepper seed
Peppers are largely self-fertile, but insects cross them within and between species. Seed saved from a pepper grown near other peppers can give unpredictable plants, including hot bells.
To save seed that comes true, grow open-pollinated (not F1) varieties, and either screen the plants from insects or keep them about 150 m (500 ft) from other peppers (UMD).
Collect from fully ripe, coloured fruit: scrape out the seeds, dry them thoroughly on a plate, and store them cool and dry.
The cross never shows in this year’s fruit, only in plants grown from its seed (Cornell).
More to Explore
Quick answers, guides that pair well with peppers, and the sources behind this one.
Frequently asked questions
Why are my pepper flowers falling off?
Usually temperature, too hot or too cold, or dry soil. See flowers and fruit set.
Are green and red peppers different plants?
Often not: a green bell is unripe, and turns red, yellow or orange if left two to three weeks longer.
How long do peppers take to grow?
About 70 to 80 days from transplanting to green fruit, plus two to three weeks to colour; add six to ten weeks from sowing.
Can I grow peppers outside in the UK?
In mild areas or warm summers, in a very sunny, sheltered spot, but they crop best under cover.
Do pepper plants need support?
A short stake helps: laden stems are brittle and snap. See support and pinching.
How often should I water peppers?
Enough to keep the soil evenly moist, about 2.5 cm (1 in) a week; pots may need daily watering. See watering.
What should I feed peppers?
In containers, a high-potash liquid feed such as tomato feed, weekly from flowering; plants in rich soil may not need it. See feeding.
Will hot peppers make my sweet peppers hot?
Not this year’s fruit. Only seed you save could produce hot plants.
Should I pinch out pepper plants?
It isn’t needed. Pinching at 30 cm (1 ft) gives more, smaller fruit but delays the crop.
How do I pick peppers?
Cut the stalk with scissors or secateurs; pulling breaks branches.
Related guides
Sources
- How to grow sweet peppers (opens in a new tab) Royal Horticultural Society
- Growing peppers in home gardens (opens in a new tab) University of Minnesota Extension
- Growing peppers in the home garden (opens in a new tab) Iowa State University Extension and Outreach
- Growing peppers in a home garden (opens in a new tab) University of Maryland Extension
- Pepper secrets (opens in a new tab) Cornell University College of Agriculture and Life Sciences
- How to grow sweet peppers (opens in a new tab) BBC Gardeners’ World