University of Vermont
Department of Plant and Soil Science

Spring News Article


Dr. Leonard Perry, Horticulture Professor
University of Vermont
If you think you know sweet peppers from the few types available in grocery stores—mainly the bell shapes—then you’re missing out on the diversity of shapes, colors, and flavors of this vegetable crop.  Because they are easy to grow, require little space, are nutritious, and come in such variety, sweet peppers were named the Vegetable of the Year for 2015 by the National Garden Bureau (
If you want the most variety, study seed catalogs and order seeds in the winter or spring.  Then, on a sunny windowsill or under indoor lights, start peppers 6 to 8-weeks before planting outside.  You can start them in late spring for planting out mid-summer, to follow crops such as lettuce, spinach or peas.
Otherwise, visit greenhouse growers in spring to buy transplants ready to set out when temperatures are warm—days at least 65 degrees and 55 degrees or more at night.  It’s better to wait until later in the spring to plant, than to plant too early and have plants not grow due to cold.  Buy plants that have been watered regularly and aren’t stressed, that have a rich green color in leaves, and preferably are not in flower yet.  Older, stunted plants that are root-bound in their tiny containers won’t transplant or establish well.  Make sure not to leave plants in a hot car on the way home, and protect them from weather extremes if not planting right away.
Make sure the site is in full sun (6 hours, preferably more, of direct sun a day). You can put black plastic over the soil prior to planting to help it heat up faster, and to keep weeds from growing.  You then can make holes in the plastic for planting.  This will help conserve moisture as plants grow, as well as control weeds.  A layer of straw on the plastic may be more attractive.
Make sure the site, if in an existing garden, wasn’t used for growing other members of this same family (tomatoes, eggplants) the previous year or two.  This is the concept of crop rotation, which helps to minimize diseases and maintain soil fertility.  Following crops from the previous year, such as lettuce and corn, to which you’ve added nitrogen works well.  You can plant peppers along with members of the same family the same year, or with carrots, onions, or peas.  For some reason they don’t grow well next to fennel or kohlrabi.
Peppers are fairly pest and disease resistant, just make sure to space properly to allow air circulation around plants.  This helps prevent any disease such as gray mold.  Spacing will vary with plant type, but should be in catalogs or on plant labels.  In general, 12 inches apart in garden beds should work for most.  In a round container or gro-bag, about 18 inches wide, you might grow 4 plants. Don’t use garden soil in containers, but rather a mix of potting soil and compost.
Peppers grow with a soil pH (acidity) of 5.5 to 7.0, but on the lower end or more acidic is better.  You can tell this, plus other nutrients, from soil test kits available at garden stores, or from local Extension Service offices.  Peppers also need adequate phosphorus and calcium.  A plant starter fertilizer with high phosphorus (the middle number of the fertilizer analysis) will provide this, plus it helps plants to get established sooner. 
Insufficient calcium will lead to a rot on the bottom of fruit—blossom end rot—just as with tomatoes.  Uneven watering, particularly during flowering and fruit set, can lead to this problem too.
Plants often benefit from a boost in nitrogen in mid-summer, such as from a side-dressing around plants of fish emulsion, blood meal, or alfalfa meal.  Too much nitrogen, though, can lead to lush growth with little flowering or fruiting.  Too hot, or too cool, also can lead to poor fruiting.

Peppers generally are ready to harvest in 50 to 90 days from planting; check descriptions in catalogs to see what is best for a particular variety.  If fruit are harvested more often and earlier, this will stimulate more production until the cooler days of fall.  Use pruners to cut fruit from plants.  There is no one right time to harvest, just keep in mind that the more fruit ripen the more they may change color (such as from green to red or orange), flavor (from slightly tart to mildly sweet), and the more nutrition they may contain.
The most common type—the sweet bell pepper—contains more vitamin C when ripe than the average orange.  In addition, one of these fruit contains high levels of vitamin E, many other  antioxidants, and less than 30 calories.  These botanically are fruit, since they come from flowering plants and have seeds, even though we know them as vegetables.  They are “sweet” since genetically they don’t contain the chemical “capsaicin” which causes the heat and burning sensation of hot peppers.
Peppers are native to Central and South America, in particular the Oaxaca area of Mexico, and have been around since 4000 to 6000 B.C.E.  Archaeology research shows they were used both as a dried ground seasoning, and fresh.  Today they are mainly eaten fresh, roasted, or frozen.  To freeze, simply wash, cut in half and scrape out the seeds, then dice or cut into strips as desired.  Spread these on trays in the freezer (“tray freezing”) to freeze them separately and not as a lump, then store in plastic freezer bags or containers.
Fruit of the common “bell” peppers have 3 to 4 lobes and are nearly as wide as tall.  Common green cultivars (cultivated varieties) that usually turn red when ripe include ‘Lady Bell’, ‘Ace’, or ‘California Wonder’.  ‘Orange Blaze’, an All-America Selections winner, turns from green to orange. ‘Flavorburst’ matures to orange, but has a sweet lemony flavor even when green. ‘Sweet Chocolate’ is named for the dark brown color, not the flavor. If your site is prone to diseases, consider ‘Red Knight’ with its resistance to several bacterial leaf spots and viruses.

Fruit of the “bull’s horn” peppers have wide tops tapering to a curved point.  They have thicker walls than the bell types, and often mature to red.  Supposedly brought to the U.S. from Italy, they may be known as “Corno di Toro” or “Horn of the Bull.”  A common and popular one of these is the bright red ‘Carmen’, another All-America Selections winner. 
Banana peppers can come in both sweet and hot, so make sure you’re buying what you want!  They are long and thin, and usually mature to red from a light green or yellow beginning.  ‘Sweet Banana’, an heirloom All-America Selections winner from 1941, is still popular.   
The “frying peppers” also may be called Italian sweet or Italian frying peppers.  They are long and begin pale green, with a thin skin.  Often fried in olive oil or baked, seeds may be left in as they impart flavor and sweetness.  ‘Cubanelle’ has elongated fruit which are good roasted when picked yellow-green, or left to ripen bright red. 
‘Giant Marconi’, early to ripen in northern gardens, has elongated fruit to 8-inches on plants to 30-inches tall.  This one, bred in Italy, is an All-America Selections winner too, and has resistance to some viruses.  The sweet, smoky-flavor of the fruit are good grilled or roasted.
There are a range of other types that don’t fit these categories.  ‘Gypsy’ is another All-America Selections winner with slightly tapered fruit that turn from yellow to orange or red when mature.  ‘Cherry Pick’ has small, rounded fruit that are usually picked green but mature to red when they are good pickled. ‘Lipstick’ is 4-inches long, tapering to a blunt tip, and maturing to a glossy red.  It is popular in gourmet salads, salsa, and cooking.
These are merely a few popular examples of the diversity of sweet peppers, which you can grow at home and many of which you won’t find in stores or markets. 

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