Plant all pepper seedlings in midspring when nighttime temperatures warm and frost lifts. These frost-sensitive plants do best when night temperatures are at 60 to 70 degrees Fahrenheit, with daytime temperatures of 70 to 80 F. Temperatures below 60 F lead to failure to establish.
Peppers grow well with other summertime plants, as they require the same season, soil quality and watering schedule. Plant them at the same time as squash, cucumbers, corn, eggplants, tomatoes, okra, pumpkins, garlic, cauliflower, radishes, carrots, watermelons, cantaloupes and strawberries.
Don't plant peppers next to tomatoes, eggplants, strawberries or potatoes. These plants share a vulnerability to the soilborne disease verticillium wilt, which wilts and stunts growth. Plant these crops at similar times and in the same garden, but keep them on opposite sides of the garden to avoid cross-contamination.
Peppers and their companions fail without the right site, soil and planting. Put vegetable gardens in spots that get full sunshine all day, good drainage and good air movement. Set aside at least 25 square feet of space for the garden to plant a full range of plants without crowding. Turn 5 inches of organic compost into the top 10 inches of soil in the garden, and add starter or balanced fertilizer to encourage rooting.