How to Grow Jalapeño, Cayenne & Sweet Peppers from Seed
A complete UK guide to Capsicum annuum, the most varied and easiest-going chilli species. Sweet peppers, Padrón, jalapeños, cayennes and Thai chillies, all grown the same way.
If you have grown a chilli or pepper before, it was almost certainly a Capsicum annuum. It is the most widely grown species by far, and the most varied: bell peppers, Padrón, jalapeños, serranos, cayennes, Hungarian wax, paprika types and small Thai chillies all belong to it.
It is also the most forgiving. Annuum germinates faster than other chillies, needs less heat, and ripens in a shorter season. Many varieties crop well in a pot on a sunny windowsill or patio, and some will do well outdoors against a warm wall in a decent British summer.
Quick Facts at a Glance
Species
Capsicum annuum
Sowing Time
February to April, under cover
Germination
1 to 2 weeks at 20 to 25°C
Harvest
July to October
Best Grown
Greenhouse, windowsill, sunny patio
Difficulty
2 out of 5, beginner friendly
Understanding the Species
Despite the name, which means annual, annuum is a tender perennial. It comes from Mexico and Central America and was the first chilli taken to Europe, which is why it dominates cooking across the world.
How to recognise it
Leaves are usually smooth and mid-green, sometimes purple or almost black in ornamental types. Flowers are white and normally appear one at a time at each leaf joint. Fruit shape varies more than in any other species, from large blocky bells to tiny upright pods.
Heat is a variety trait
Heat in annuum ranges from none at all in sweet peppers to habanero level in a few varieties such as Dalle Khursani. The growing method stays the same whether the fruit is sweet or fierce.
Handling hot varieties
Wear gloves when cutting or deseeding hot chillies, and keep your hands away from your eyes and face. Capsaicin oil stays on skin for hours.
Treat very hot varieties such as Dalle Khursani as superhots: wear gloves and eye protection when picking and processing the fruit.
Our annuum varieties
A close relative: Capsicum frutescens
Our African Birds Eye (piri piri) is a Capsicum frutescens, the species that also gives us Tabasco. It is grown in much the same way as annuum, but likes a little more warmth and a longer season, so sow it in February and grow it under glass.
When & How to Sow
Sow from February to April. Sow large sweet peppers and the hotter, later varieties in February, and quick, compact chillies in March or April.
Don't sow too early
Annuum grows quickly. Without grow lights, a January sowing often produces leggy plants that have outgrown their pots long before it is warm enough to move them on.
Sow shallow and warm. Sow seed 5mm deep in moist seed compost, in small pots or modules, and keep at 20 to 25°C. A propagator helps but a warm windowsill will often do.
Watch for seedlings. Most seed germinates in one to two weeks. Move seedlings into good light as soon as they appear.
Pot on. Move into 9cm pots at two or three true leaves, and on again into 2 to 3 litre pots as the roots fill them.
Final position. In May or June, move into 5 to 10 litre pots, a greenhouse bed or growbag. Outdoor plants go out only after the last frost, once nights stay above 10°C.
Growing On Tips
Where to grow
A greenhouse gives the biggest crops, but compact varieties do well on sunny windowsills and patios.
Outdoors
In a warm summer, varieties such as Hungarian Hot Wax, Padrón and cayennes crop against a sunny, sheltered wall.
Water evenly
Let the compost surface dry slightly between waterings. Avoid both waterlogging and wilting.
High-potash feed
Feed weekly with tomato feed once the first flowers open.
Pick to keep cropping
Picking fruit regularly, even green, encourages more flowers and fruit.
Support
Large-fruited peppers and tall plants need a cane to carry the crop.
Overwintering
A healthy plant brought into a bright, frost-free room at 10 to 15°C in October, cut back hard and kept on the dry side, will crop earlier the following year. Compact and ornamental types overwinter most easily.
Common Problems & How to Fix Them
| Problem | Likely Cause | What to Do |
|---|---|---|
| Leggy seedlings | Sown too early or too little light | Sow from February, or use a grow light. |
| Flowers drop off | Heat, cold nights or dry compost | Ventilate on hot days, keep plants warm at night and water evenly. |
| Sunken black patch on fruit | Blossom end rot from irregular watering | Water consistently, especially in pots. |
| Sweet peppers stay green | Colour change takes weeks | Be patient; allow three to four weeks after full size. Green peppers are fine to eat. |
| Sticky leaves, curled tips | Aphids | Squash or rinse off early and encourage natural predators. |
| Pale, mottled leaves | Red spider mite in hot, dry conditions | Damp down and mist regularly. |
When to Harvest
Most annuum varieties crop from July to October. Pick Padrón small and green, jalapeños green or red, and cayennes and sweet peppers once fully coloured for the fullest flavour. Frost ends the season for outdoor plants.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 🌱 Sow under cover | ||||||||||||
| 🪴 Final pots / out | ||||||||||||
| 🌶️ Harvest |
Species Specifications
Sweet, smoky or fiery, from a sunny windowsill
Sow in spring, pot on as they grow, and pick your own peppers and chillies from midsummer. Choose from 22 annuum varieties.
Shop Padrón Seeds →
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