Thai Chili Pepper

Thai chili, also called bird’s eye chili, is a very hot pepper of the Capsicum annuum species. Its fruit is a shiny, tapered berry about 1 to 3 inches (2.5 to 7.6 cm) long, and it comes in several colors. Bird’s eye chili, also called the Thai chili pepper, is rated at 50,000 to 100,000 Scoville heat units. The heat comes from capsaicin, and the level varies widely between types.

Sowing. Start seeds indoors 8 to 10 weeks before the average frost-free date. Plant seeds ½ inch (1.3 cm) deep, several to a spot, and thin to one plant after the seedlings have two leaves. Seeds germinate at about 80 °F (27 °C) until the root emerges. Pepper seeds germinate very slowly in cool soil, so aim for 80 to 90 °F (27 to 32 °C) where you can.

Transplanting. Wait until the soil reaches about 65 °F (18 °C), since planting earlier can leave plants stalled. Don’t plant out until after the last chance of frost. Space plants 12 to 24 inches (30 to 61 cm) apart in rows; other guides use 18 inches (46 cm).

Site and habit. Give plants full sun, at least 6 hours of direct sunlight a day. Pinch out early flower buds and small fruits to get stronger, bushier plants. Stems can be brittle, so support them with cages or short trellises. The species is a woody perennial, but in the UK it is usually grown as an annual because it is hard to keep alive over cool months.

Watering. Keep the soil evenly moist and don’t let it dry out between waterings once fruit forms. Deep, infrequent watering of about 1 to 2 inches (2.5 to 5 cm) a week works well, and mulch helps hold in moisture.

Feeding. Test your soil and follow the results. Too much fertilizer encourages leafy growth and delays fruit.

Heat. Evening temperatures above 75 °F (24 °C) slow or stop pod production, so afternoon shade helps.

Pests. Watch for aphids, whiteflies, slugs and pepper maggots, among others.

Diseases. Bacterial wilt and bacterial leaf spot are the most troublesome diseases in home gardens. Rotate planting spots and don’t plant peppers in the same spot more often than once every three years.

Blossom end rot. Fruit that rots dry, brown or black at the flower end can come from uneven watering.

Picking. Pick peppers when they reach full size and feel firm. Cut the stems instead of pulling to avoid breaking branches. Hot peppers can be picked green or left to ripen and change color on the plant.

Store peppers at 45 to 50 °F (7 to 10 °C) in moist conditions for about 2 to 3 weeks. Don’t store them below 35 °F (2 °C), because they are prone to chilling injury.

Handling. Hot chilies can burn if not handled carefully, so wear rubber gloves when cutting or cleaning them and avoid touching your face. Wear gloves when processing chiles or cleaning seeds.

Eating. The fruit is edible raw or cooked, but it can be very hot. A general plant database field rates the fruit, leaves and seeds as low-severity, toxic only when large amounts are eaten. That field is a general database entry, not a food-safety instruction.