In USDA zones 11 and above, chili peppers grow like weeds. In these tropical regions, they can be seeded outdoors at any time of the year. Choose a well-draining and cultivated location that has been amended with 6-8 inches of rich compost. Broadcast your chili seed across the planting bed and top with 1/4 inch of soil. Thin the plants to 1-2 foot spacing when they sprout.
In USDA zones 5 and below it is best to grow them year-round under plastic in a greenhouse or polytunnel. These areas typically receive about 100 days or less of frost-free weather and may have trouble bringing the fruit into maturity without additional protection.
For the zones between 5-11, seeds are sown indoors 8-12 weeks before the last frost date in the region. Keep them at temperatures of around 70°F (21°C). Seeds will sprout within 5 days. Use a standard potting soil mix for your seedling trays.
Once sprouted, trays will need to be placed under flourescent lights to prevent the plants from stretching out toward the sun. Here is a chili pepper planting guide:
- Start indoors 8-12 weeks before last frost
- Ideal germination temperature 70°F (21°C)
- Place under lights when sprouted
- Transplant outdoors 2-3 weeks after last frost
Always acclimate plants before transplanting outdoors. Plants need to adjust to receiving direct sunlight, withstanding wind, and dealing with the day and night temperature changes. Acclimating them takes up to one or two weeks.
Begin by bringing seedling trays outdoors for 1/2 hour on the first day. Gradually increase the time they spend outdoors, the amount of direct sunlight they receive and begin to leave them out in the evenings to get them used to sinking nighttime temperatures. They are ready to transplant once they show no signs of stress after being outdoors for 24 hours.
Space them 2-3 feet apart in an area of the garden with full sun. Amend the soil with 6-8 inches of rich compost either worked in or placed on top.
Care and Harvest
Feed plants using liquid compost tea when they begin to set fruit. Add powdered oyster shell or bone meal to the bed for extra calcium. Harvest chili peppers either in their green stage or wait until they turn bright shades of yellow, orange, or red.