Sow chillies in February, as hot ones need a long season

Chillies are among the first seeds of the year. Sow them indoors from late January to early March. They grow slowly, and the hottest varieties need every week of the season to ripen their fruit before the autumn.

Mild chillies and jalapeños can wait until late February or early March. Habaneros, scotch bonnets and other very hot types are best sown in late January or February.

Starting chillies off

Chilli seed needs warmth to germinate, ideally around 25 °C. A heated propagator, the top of a warm (not hot) radiator shelf or an airing cupboard all work.

1. Fill small pots or modules with seed compost and water them.
2. Sow two or three seeds per pot, about 0.5 cm deep.
3. Cover with a clear lid or a plastic bag, and keep them warm.
4. Check daily. The seedlings come up in one to three weeks.
5. As soon as they appear, move them into the brightest light you have and take off the cover.

Light matters as much as heat. In February a windowsill is dim, and seedlings stretch towards the glass. Turn the pots every day, or grow them under an LED grow light for the first few weeks.

Potting on

When the seedlings have two or three true leaves, move each into its own 8 cm pot. As roots fill each pot, move them up again, to around 2 litres for planting outside or 5 to 10 litres for growing in pots.

Keep them somewhere warm and bright, and water when the top of the compost is dry. Chillies dislike sitting wet.

Planting out

Chillies are killed by frost and sulk below about 10 °C. The dates here are for a typical lowland garden in England or Wales, with a last frost around 20 April.

• Greenhouse or polytunnel: from early May.
• Outdoors: from late May to early June, after hardening off for a week, in your sunniest, most sheltered spot. In Scotland and the north, keep chillies under glass or on a sunny windowsill.

Space plants about 45 cm apart, or grow one per large pot. Basil, marigolds, carrots and onions grow well nearby.

Feeding and ripening

Once flowers appear, feed weekly with a high-potash liquid feed such as tomato food. Tall plants may need a short cane.

Chillies crop from mid-July to late October, about 70 to 100 days after planting out. Pick them green for a fresher, milder taste, or leave them to colour fully for more heat and sweetness. Regular picking encourages more flowers.

Before the first frost, around the end of October, pick every fruit. Plants in pots can come indoors to finish ripening, or to overwinter on a cool, bright windowsill.

Common problems

Slow seedlings. Too cold. Find a warmer spot until they’re growing well.

Flowers dropping. Very hot or very cold nights, or dry compost. They usually set fruit again when conditions even out.

Aphids. Clusters on the shoot tips, especially indoors. Squash them or wash them off.

Fruit not ripening. Not enough warmth or a late start. Sow earlier next year, and grow the hottest varieties under glass.

For chillies grown indoors all year, see growing chillies on a windowsill. Set your own frost dates on the chilli page.