In the UK, chilli seeds should be sown early in the year, ideally grown in a greenhouse or polytunnel. While they can thrive outdoors in a sunny spot during peak summer, starting them indoors ensures better success. Germination times vary between varieties, taking up to five weeks, but most seeds sold on our site germinate within 10-14 days, some even faster. Below are tips and techniques to give your chilli plants a strong start and successfully grow them in pots.
For optimal drainage, use soil-based composts or sow seeds in pure vermiculite. A loam-based seed compost like John Innes is ideal for germination. Vermiculite, being sterile and nutrient-free, reduces disease risk and makes transplanting easier by minimizing root disturbance.
Warmth is crucial for fast and consistent germination. Use a heated propagator or place seed trays in a warm environment. Keeping the compost between 27-32°C (80-90°F) yields the best results. Lower temperatures down to 21°C (70°F) can work but slow germination, while temperatures above 38°C (100°F) may reduce success rates.
Watering is best done from the surface using a spray bottle, as it maintains compost temperature and prevents overwatering.
The best time to sow is February or March, but later sowing is possible. Maturity times differ by variety, with some taking 60 days to produce ripe fruit and others up to 120 days. Varieties like Habaneros require an early start as they need at least 3-4 months from potting to ripen.
Sow seeds about 5mm deep in small pots, grouping seeds of the same variety together. Once most seedlings have two leaves and are not leggy, transfer them to 3-inch pots. Handle seedlings by their leaves, not stems, to avoid damage. For those with sufficient propagator space, sowing directly in larger pots is also an option.
Relocate seedlings to a well-lit area, such as a heated greenhouse or conservatory, ensuring they remain warm, moist, and ventilated. Keep them in 3-inch pots until they reach 3-6 inches tall.
When plants develop about five leaf pairs, transfer them to larger pots (9-12 inches, depending on variety). For compact ornamental varieties, smaller pots suffice. In polytunnels or greenhouses, planting directly into soil is another option. During intense summer heat, provide shade to prevent stress.
Maintain temperatures below 36°C and avoid excessive nitrogen, as it encourages foliage over fruit. Ensure consistent watering to prevent blossom or pod drop. Support larger varieties with canes, and consider moving ornamental types to patios or bright indoor spaces once established. Mist plants to combat low humidity, and use balanced feeding to encourage flowering.
Harvest time depends on the variety and desired ripeness. Many fruits ripen from green or yellow to red, but others may turn orange or yellow. Pick when the fruits are firm, glossy, and full-flavored. Regular picking encourages further fruiting, and extras can be frozen for later use.
Chilli plants can often be treated as perennials. Place them on a sunny windowsill, water sparingly with tepid water, and prune larger varieties if necessary.
