Hot or sweet; hybrid or open pollinated; green, red, yellow -- even brown -- peppers are garden favorites. Whether you grow them to enjoy raw in salads, cooked in your favorite stir-fries and ethnic dishes, or dried and strung into ristras, peppers offer a wide array of colorful and tasty choices. Peppers are New World natives, first brought back to Europe by Columbus and now an important addition to cuisines around the world. Their globe-spanning history opens interesting avenues of exploration that can complement their culture in a school or youth garden.
Peppers fall into two main categories – hot and sweet. Sweet peppers (kind of misnomer as all have little to no heat, while only some have a sweet taste) include the sweet bell peppers with their familiar blocky shape, as well as varieties with long, tapered or rounded fruits. The mature color of sweet pepper varieties may be red, orange, yellow, brown or purple.
Hot pepper varieties also come in an array of shapes, sizes as well as levels of heat, from tiny, fiery red bird’s eye chilies to relatively mild jalapenos to moderately hot ‘Big Jim’ chilies that can reach as much as a foot long!
How hot is hot? A pepper’s heat comes from compounds within the fruits called capsaicins. The heat is rated using the Scoville Heat Scale, which was developed in 1912. The scale, in Scoville Heat Units (SHU) goes from 0 SHU for mild bell peppers all the way to well over 1,000,000 SHU for the hottest varieties. The heat varies with the variety of hot pepper (habaneros are hotter than jalapenos, for example) as well as the weather and growing conditions – hot weather and drought stress produce hotter peppers.
Whether you’re growing sweet or hot peppers, keep your growing conditions and climate in mind when choosing varieties. If you garden in a short-season area, look for ones that mature relatively quickly and that perform well under cooler conditions; in warm, humid areas, choose varieties with good disease tolerance.
Site: Plant peppers in well-drained soil that is rich in organic matter in a location that receives full sun. To minimize insect and disease problem, use a three year rotation for the location of peppers and related crops (eggplant, tomatoes, potatoes) in your garden space.
When to plant: If you are growing your own transplants, start pepper seeds 8 to 10 weeks before their planting-out date, which is generally 2-3 weeks after the last spring frost date. Don't put peppers out too early; young plants exposed to overly cold conditions may survive, but they won't bear well. Bottom heat will speed seed germination, and the young seedlings will appreciate warmer temperatures for growing on. If you can, give them daytime temperatures of 70-75 degrees F, with a drop to 65 degrees F at night. Use lukewarm water when you water. And give them plenty of bright light as soon as germination occurs.
Planting: Make sure transplants are well hardened off before they go out in the open garden. Transplant when the soil is warm, all danger of frost is past, and night temperatures stay reliably above 50 degrees F, generally 2-3 weeks after the last spring frost date. Gardeners in short season areas can use black plastic to pre-warm the soil and give plants some extra protection by setting them in a cage enclosed in clear plastic or row cover fabric. Be sure to vent plants on warm days and remove the covers as the weather warms.
Set homegrown or purchased pepper plants 14-18 inches apart. Plant them at the same depth as they were growing in the pot when you transplant them to the garden.
Give your plants some support. Pepper plants may not reach the same heights as tomatoes, but they can get top heavy when they are loaded with fruit, causing branches to break or the entire plant to topple over in the wind. Use cages or stakes to help keep plants upright.
Place cutworm collars around transplants at planting time. Cutworms are night-feeding caterpillars that would love nothing better than to chomp through the stems of your carefully nurtured transplants once you set them in the garden. Encircle each stem with collars fashioned from sections of toilet paper or paper towel tubes, old tuna cans, or cut-down yogurt containers or wrap the base of stems in multiple layers of newspaper.
Care: Keep soil moisture consistent. Peppers won't tolerate soggy soil, but they do need consistent moisture in well-drained soil to do their best. Fluctuations in soil moisture can lead to problems like blossom end rot, which causes dark, leathery spots to form on the blossom end of the fruit.
Make sure plants are well-fed, but don't overdo the nitrogen. Peppers need a balanced supply of nutrients, but too much nitrogen will encourage lots of leaves and fewer fruits. Start out with soil that's been amended with compost; then sidedress plants lightly with a balanced fertilizer as they come into flower and again about three weeks later.
- Sunscald: Just as you can get sunburn if you are out in the bright sun too long, peppers can develop sunscald when they are exposed to too much hot sun directly on the fruits. The affected area first gets soft, wrinkled, and lighter in color. Later, the damaged tissue turns dry and sunken. Eventually black mold may begin to grow. Sunscald develops when there isn't enough foliage to shield plants from intense sunlight and is often more of a problem in warm-climate gardens. To prevent problems, keep plants well-leafed and growing vigorously by fertilizing and watering properly. If you garden in a hot, sunny climate, set plants so that they get some shade from taller plants at midday. If just small sections of a pepper fruit are damaged by sunscald and there is no mold present, you can still eat the fruit if you cut away and discard the damaged sections. But if mold is growing, discard the entire pepper.
- Blossom drop: Peppers may drop their blossoms and stop producing fruits if the daytime temperatures remain above 90 degrees. Hot peppers tend to be more tolerant of high temperatures than sweet peppers. If you garden where summer temperatures soar, be sure to keep the soil consistently moist and use an organic mulch rather than plastic to help keep the soil cool. Covering plants with shade cloth stretched on supports may help, or place them in the garden where they'll get some afternoon shade from taller plants nearby.
- Blossom end rot. The blossom end of the fruit (furthest from the stem) turns black and leathery. This is the result of a lack of calcium in the fruit as it is forming. Usually there is plenty of calcium in the soil, but the roots of the plant are not able take up enough due to factors such as a sudden decrease in soil moisture, root damage from cultivating too close to the plant, or planting in cold, heavy soil. To control this problem, try to keep soil moisture consistent; mulch plants to conserve moisture and keep weeds down; and wait until the soil is warm before planting.
Harvesting: Peppers can be harvested green as soon as they are a usable size, or they can be left on the plant to ripen to their mature color. Hot peppers will develop more heat as they turn to their mature color, so if five-alarm chili is your goal, let them ripen completely on the plant. The stems of peppers are brittle, so the safest way to harvest is with scissors, rather than trying to pull peppers off by hand. The more you harvest, the more peppers your plants will produce. When harvesting hot pepper varieties wear gloves and avoid touching your eyes.
The world’s hottest pepper is reputed to be the Carolina Reaper, with a Scoville rating of 1,569,300 SHU – 500 times hotter than a Tabasco pepper. Ouch!
- The jalapeno pepper is the official state pepper of Texas.
- Bell peppers are nutritional all-stars! A large red bell pepper delivers three times the vitamin C of an orange, along with Vitamin A and the healthful antioxidant lycopene.
- All peppers are members of the genus Capsicum. Most of the peppers we eat, both sweet and hot, are from one species, Capsicum annuum. But a few of the hottest peppers we eat come from four other species: C. baccatum, C. chinense, C. frutescens,and C. pubescens.