Site. Grow peppers in full sun (at least 6 hours per day) in soil that is rich in organic matter, moisture retentive but well draining. Peppers prefer a soil pH of 6.0 to 6.8. If the pH is below 6.0 add limestone to the soil; if the pH is above 8.0 add peat moss to lower the pH. A safe bet is to always work aged garden compost into beds prior to planting. The optimal soil temperature for peppers is 65°F (18°C) or warmer. Choose a site protected from wind. Avoid planting in beds where other members of the Solanaceae family (peppers, eggplants, tomatoes, and potatoes) have recently grown. Some peppers such as Jalapeño, cayenne, and mirasol prefer arid regions; others such as habanero, Scotch bonnet and datil prefer humid regions.
Planting time. Hot peppers grow best in daytime air temperatures 65° to 80°F (18-26°C) and night temperatures above 55°F /13°C (nighttime temperatures between 60° and 70° are best). Peppers are most easily grown from transplants. Start seed indoors 7 to 10 weeks before the date you intend to set peppers into the garden. Peppers can be seeded in the garden or transplanted out 2 to 3 weeks after the last frost in spring after the soil temperature has risen to at least 65°F. In temperatures greater than 85°F (29°C), peppers may drop their blossoms although set fruit will ripen. The ideal temperature for hot peppers is a daytime temperature around 75°F (24°C) and a nighttime temperature around 62°F. Generally, you can set out peppers at the same time you set tomatoes or basil into the garden.
Planting and spacing. Sow hot pepper seeds ¼ to ½ inch deep, 18 to 24 inches (45-61 cm) apart depending upon the variety. Space rows 24 to 36 inches (61-91 cm) apart. Sow three seeds to each spot and thin to the two most successful seedlings. Peppers can be transplanted into the garden when they are 4 to 6 inches (10-15 cm) tall.
Water and feeding. Keep peppers evenly moist but not wet particularly when blossoms appear and fruit begin to form. Soil that goes too dry can result in flower drop. Keep the soil evenly moist just after transplanting peppers to the garden; avoid under or over watering peppers early on. Add aged compost to planting beds before planting and again at midseason.
Once hot pepper plants are established you can vary the watering. Hot peppers that are deprived of water and become slightly stressed will produce more pungent fruit.
Companion plants. Beets, garlic, onions, parsnips, radishes.
Care. Keep planting beds well weeded to avoid competition. Peppers are shallow-rooted, so cultivate around peppers with care. Mulch to keep soil temperature and moisture even.
Avoid high nitrogen fertilizers which will create large leafy plants with few or no fruits. High temperatures and wind can cause flowers to drop and plants not to set fruit.
Plastic mulch can improve pepper yields. Organic compost mulches will reduce weeding and watering, but not fruit yields.
Hot peppers can put out shoots that become leggy. Cut these shoots back to keep the plant compact.
Peppers will begin to flower almost as soon as the plant forms branches. Pepper plants have complete flowers which means each flower contains both a male and female part; as a result, the pepper is self-pollinating. Wind, bees and other insects, and a light shake of the plant by a human hand can aid pollination.
Container growing. Peppers can be grown in a large container. An 8-inch (20 cm) pot will accommodate a single plant. In larger containers, set plants on 12 inch (30 cm) centers. Peppers can be grown indoors. Peppers started indoors before the last frost in spring will get a head start on the season. Extend the season in the fall by moving plants indoors if frost threatens or if temperatures warm to greater than 90°F (32°C). Bring outdoor started peppers inside for a few hours a day at first until they get used to the lower light available indoors.
Pests. Peppers can be attacked by aphids, cutworms, flea beetles, and hornworms. Discourage cutworms by placing a collar around each transplant at the time of planting; hand pick hornworms off of plants. Flea beetles and aphids can be partially controlled by hosing them off the plants and pinching out infested foliage.
Diseases. Peppers are susceptible to rot, blossom end rot, anthracnose, tobacco mosaic virus, bacterial spot, and mildew. Plant disease-resistant varieties. Keep the garden clean and free of weeds where pests and diseases can shelter. Remove infected plants before disease can spread. If you smoke, wash your hands before working with the plants to avoid spreading tobacco mosaic virus.
Harvest. Hot peppers are ready for harvest in 60 to 95 days after sowing depending upon the variety. Most hot peppers mature from green to red as the seeds inside mature. Green hot peppers are not ripe, although some people prefer the flavor of green hot peppers. Red peppers are ripe and have a fruitier flavor. The hottest chili peppers are usually orange colored. Cut the peppers off the vine. Pulling a pepper away from the plant may cause the plant to come out of the soil. To prolong the harvest, cut peppers from the plant regularly; a hot pepper harvest can last from one to three months.
Harvest safety. Hot peppers contain organic chemicals called capsaicinoids which can burn the skin and eyes. Wear rubber gloves when harvesting hot peppers and be careful not to rub your eyes. The best antidote for burning skin to to rub them with isopropyl (rubbing) alcohol.