Peppers originated from Central and South America and were thought to be domesticated around 7500 B.C. Columbus brought them back to Europe and they were quickly adopted into the culture. Eventually they were brought over to North America. Due to the short growing season, peppers are typically started indoors or in a greenhouse in Wisconsin before being transplanted outside once the soil temperature warms appropriately. With the right preparation, you can have a long and bountiful harvest of tasty peppers.
Fill individual cell seed trays 3/4 full with sterile potting mix. Ideally the mix should contain sphagnum peat moss, perlite and potting soil.
Place one pepper seed per cell and sow at a depth of 1/2 inch. Keep the soil moist but not soaked. It should easily crumble in your hands. Place in a sunny location and keep the temperature between 80 and 85 degrees F until germination occurs. Utilize a seed heating mat if the area you're germinating them in isn't this warm. Expect germination in 8 to 25 days. Once germinated the temperature can be lowered to 70 degrees F.
Transplant each pepper plant to a 3-inch pot once they grow two sets of mature leaves. To do this, add a small amount of soil to the bottom of the 3-inch pot. Loosen the soil around the edge of the cell where the pepper plant is. Grasp the plant and gently pull it out of the cell. The root ball and soil will come out easily. Place the plant in the center of the 3-inch pot and add soil until the soil level is the same as it was in the cell tray.
Transplant the pepper plants into your garden once soil temperature reaches 60 to 65 degrees F. Typically in Wisconsin this is in early June. Dig a hole and place one plant per hole at the same depth that it was in the pot. Space plants 12 to 18 inches apart and rows 24 to 30 inches apart.
Provide irrigation to your pepper plants so that they receive 1 inch of water per week. Spread a 2 to 3 inch layer of mulch around your plants to help retain soil moisture.