Temperature
Ideally, peppers seeds will germinate at temperatures between 70-80°F (21-26°C). Plant bell pepper seeds outside well after the last frost date in your region. Daytime temperatures should be consistently reaching 70°F (21°C) and the soil temperature should be a solid 65°F (18°C) for planting peppers.
Peppers will need between 60-100 days above freezing to fully mature and will not tolerate a frost. Each variety is slightly different. If you live in a region with shorter growing seasons, start pepper seeds indoors before the last frost to achieve worthwhile production.
Commercial growers in northern climates will cover the soil with black plastic to warm it before planting. This gives a slight headstart and keeps germinating seeds warm.
Starting Indoors
Start pepper seeds indoors 8-12 weeks before the last frost date in your region. Germinate seeds in potting soil, or fold into wet paper towels to speed up the process. Store germinating seeds somewhere warm as close to ideal germination temperature as possible.
Plan on keeping seedlings indoors until three weeks after the last frost. This will require some transplanting and possible pruning indoors before plants go outside. Some northern gardeners prefer to keep peppers in greenhouses or polytunnels all season long.
Checklist for starting bell peppers:
- Germinate at temperatures around 70°F(21°C)
- Plant outside once soil temperature reaches 65°F(18°C)
- Plant outside 2-4 weeks after last frost
- Start seeds indoors in USDA zones 8 and below
Transplanting
Depending on when you started your seeds, you may have some significant plants to transplant outside when the weather is warm enough. Before plants can go directly into the garden, they should be hardened off.
Harden off seedlings by bringing them outside for more and more time each day. Start by bringing them outside into dappled light for a half hour. Over the course of two or three weeks, increase the amount of time they spend outside and the intensity of the light they receive.
Plants can be successfully transplanted into the garden when they show no signs of wilt or browning after being outside for 24 hours. They should be acclimated to direct sunlight, temperature shifts between day and night, wind, and rain.
