Many different kinds of peppers can be grown in Illinois home gardens, said Maurice Ogutu, U of I Extension horticulture educator. "The most popular types are the sweet bell peppers, hot types, and other specialty types like Hungarian and chilli peppers. The sweet bell pepper types have different colors such as green, red, yellow, pink, and orange. Peppers are harvested when fruits are immature but have reached full size, and they are used in salads and for flavor in many cooked dishes."
Pepper is a warm-season crop that does well when temperatures are warm, he noted. Plant peppers when the danger of frost is past in spring. Pepper does well in full sun when day temperature is in the 70-80 degrees F range and night temperature is 60-70 degrees F. Flowers drop when day temperature is above 90 degrees F and also when night temperatures are below 60 degrees F. Water stress at bloom time can also lead to blossom drop, and may also lead to blossom end rot on fruits.
"Select a site with well-drained fertile soil, away from trees and shrubs to avoid competition from roots of trees and shrubs, and where plants can get full sun (six to eight hours of direct sunlight in a day)," he said. "You can test your soil and adjust fertility and pH based on soil test results. The best soil pH range for pepper is 6.0 to 6.8. You can get a list of soil testing labs through your local Extension office. The fertilizers with low nitrogen like the ones with 1-2-2 ratios such as 5-10-10 or 8-16-16 are often used when growing peppers in home gardens."
There are several varieties of peppers, and the choice depends on the gardener's preference, and varieties that are well adapted to the area. "There are some standard varieties that home gardeners are more familiar with while there are other hybrids and specialty types that home gardeners can grow as well," Ogutu said.
You can order seeds through catalogues or buy plants at local garden centers or farmers' markets. Some of the commonly grown varieties in Illinois are: green sweet types - Ace, California Wonder, North Star, Lady Bell, Jupiter, Big Boy, Snapper, Red Knight; Yellow sweet types - Summer Sweet, Sunray; Orange sweet types - Gourmet; Banana type - Sweet Banana; Hot types -Hungary Wax, Long Red Cayenne; Pimento types - Sunnybrook, Early Pimento.
"Peppers are usually grown in Illinois home gardens using transplants," he said. "You can buy transplants from local garden centers or farmers' markets, or some home gardeners may start their own plants from seeds."
Pepper seedlings need to be started at least eight weeks before the planting date by sowing seeds one-fourth-inch deep in shallow flats, and after germination they can be transferred into two-inch cell-type flats.
"For faster germination maintain the media temperature at 80-90 degrees F," he recommended. "Harden plants by exposing them to outside conditions gradually before transplanting outdoors. When buying transplants from local garden centers, select stocky, sturdy plants with three to five sets of true leaves, and avoid plants with flowers or fruits."
Pepper seedlings need to be transplanted 18 inches apart within rows that are 24 or more inches apart.
"Water plants thoroughly after transplanting," he said. "After the plants are well established, apply straw mulch or grass clippings around the base of plants to conserve moisture and control weeds. Weeds that emerge through the mulch can be hand pulled. Once fruit begin to set, plants need to be sidedressed with fertilizers such as 10-10-10 based on recommendations on the package to help promote greater plant productivity."
Water plants early during the day so that leaves dry during daytime in order to minimize diseases. Control insect pests such as aphids with insecticidal soap, and control other insect pests and diseases by following recommendations in the Illinois Home, Yard, and Garden Pest Guide. Provide plants with uniform soil moisture to avoid blossom end rot, ensure plants have adequate foliage to protect fruits from sunscald, and try to keep water off the leaves in order to control foliar diseases.
"Bell peppers are usually picked when they reach full size and are firm to encourage further fruit set," Ogutu said. "Other pepper types are usually picked at full maturity.
"Care should be taken when harvesting the fruits as branches are very brittle. In order to avoid excessive breakage of the branches, hand pruners or clippers can be used. The number of fruits per plant varies with the variety. Pepper fruits have a short shelf-life and need to be stored for two to three weeks under cool moist conditions. After harvesting, wash the fruit and store at 45-50 degrees F and relative humidity of 85-95 percent."