Peppers and chillies are warm-climate plants with a long season, so the single most important thing when growing them from seed is to start early and keep them warm. Sown too late or grown too cold, they sulk; given heat and a long run, they crop generously.
Start early, indoors
Because peppers need many weeks from sowing to ripe fruit, sow indoors well before the last frost — often late winter to early spring. Chillies, especially the hotter types, take longest and should be sown earliest.
Warmth for germination
Pepper seed germinates slowly and erratically, and it needs warmth — steady warm temperatures, ideally with bottom heat from a heat mat, dramatically improve and speed germination. In cool conditions seed can take weeks or rot before sprouting. Sow about 0.5 cm deep in fresh seed compost and keep it moist, not wet.
Growing on and potting up
Give seedlings strong light as soon as they emerge to prevent them growing leggy, and pot them on into larger pots as they fill their containers. Keep them warm throughout — peppers are cold-sensitive and check badly if chilled.
Hardening off and planting out
Do not rush plants outside. Only after all frost has passed and nights are reliably warm should you harden off plants gradually over a week or two and move them to their final spot — a warm, sunny, sheltered position, a container, or best of all a greenhouse or polytunnel in cooler climates. See protecting plants from cold.
Support, watering and feeding
Stake taller plants, which can become top-heavy with fruit. Water consistently and, once flowering, feed with a high-potassium (tomato) feed to support fruiting. Warmth and sun drive ripening.
Common problems
Slow or no germination is almost always too little warmth. Flower or bud drop occurs in temperature extremes — too cold or above about 30 °C (see flower and bud drop). Sunscald can mark exposed fruit in fierce sun; aphids favour soft new growth; and cold, wet roots invite rot. Leggy seedlings mean more light is needed.
Harvesting
Pick sweet peppers green for higher yields, or leave them to ripen to red, yellow or orange for sweeter flavour. Chillies can be picked at any colour but grow hotter and sweeter as they ripen fully. Regular picking encourages more fruit.
Sweet peppers or chillies — and choosing a variety
The same growing rules cover sweet (bell and pointed) peppers and hot chillies, but chillies — especially the fiery Capsicum chinense types like habanero — need the longest, warmest season and the earliest sowing. In cooler climates choose quicker-maturing, smaller-fruited varieties, which ripen far more reliably than large blocky bells.
Light and potting on
From the moment they germinate, peppers need strong light or they stretch and weaken; a bright windowsill in midwinter is rarely enough, so a grow light helps. Pot seedlings on step by step as roots fill each container rather than moving them straight into a huge pot of cold, wet compost, which invites rot.
Greenhouse versus outdoors
In warm climates peppers crop well outdoors in a sunny, sheltered bed or container. In cool-summer regions they are far more productive under cover — a greenhouse, polytunnel or even a sunny conservatory — where the extra warmth ripens more fruit before autumn.
Overwintering
Peppers are actually short-lived perennials. In a frost-free, bright spot a healthy plant can be cut back and kept over winter to crop earlier and more heavily the following year — water sparingly during the cold months and resume feeding as growth restarts in spring.
Feeding, pollination and ripening
Peppers are hungry once they start fruiting. Feed container plants regularly with a high-potassium (tomato) feed from the first flowers onward to support a heavy set, and keep watering even — drought at flowering causes buds to drop, while soggy roots cause rot. Like tomatoes, peppers are self-fertile, but under glass or on a still balcony a gentle daily tap of the flowering plant helps pollen transfer and improves fruit set. Ripening to full colour takes warmth and time: the more sun and heat the plant gets late in the season, the more fruit will turn from green to red, yellow or orange and sweeten. In a poor summer, pick some fruit green to take the load off the plant and let the rest ripen, or ripen near-mature fruit indoors on a warm windowsill.
Getting a long enough season
The single biggest reason peppers disappoint in cool climates is simply running out of warm season. Sowing early with bottom heat, growing on without any chilling checks, and finishing the plants under cover all stretch the season at both ends. Choosing faster, smaller-fruited varieties over large bells is the easiest way to guarantee a ripe crop where summers are short.
Related guides
Part of our Vegetable Gardening guides.
- Seed germination & starting seeds
- Damping-off in seedlings
- Flower & bud drop
- Vegetables for a greenhouse
