Growing Peppers

Peppers (Capsicum annum, C. chinense) can be sweet or hot, tiny or a foot long, and range in color from green, yellow and orange to red, purple and brown. Sweet peppers include banana, bell, cherry and pimiento types. Hot peppers include ancho, chili, habanero, jalapeño, hot banana and serrano types. The compound that makes peppers taste hot is capsaicin, which is found in the seeds and the whitish membrane inside the fruits. Removing the seeds and membrane before cooking or eating raw reduces the hotness of peppers.

Quick Tips

• Start peppers from seeds indoors about eight weeks before planting outside.
• If you buy plants from a garden center, choose sturdy plants up to a foot tall.
• Remove any blooms on transplants purchased at garden centers to encourage more leaf growth when transplanted.
• Transplant outdoors after nighttime low temperatures are above 50 degrees.
• Use black plastic mulch to warm the soil, decrease weed growth and reduce soil moisture loss.

Soil pH and Fertility

Peppers prefer organic, rich, well-drained, sandy soil for best growth. Most soils will grow peppers provided they are well-drained and fertile. Before planting, incorporate 2 to 4 inches of well-composted organic matter or apply 4 to 6 cups of all-purpose fertilizer per 100 square feet. Work this into the top 6 inches of soil.

Have your soil tested to determine pH. Peppers do best in soil with pH between 6.5 and 7. Apply phosphorus and potassium according to soil test recommendations. Too much nitrogen fertilization will lead to plants that are bushy, leafy and slow to bear fruit. Do not use any fertilizer containing a weed killer, as it may kill your vegetable plants. You can improve your soil by adding compost in spring or fall. Do not use fresh manure though, as it may contain harmful bacteria and increase weed problems.

Selecting Plants

If you buy plants from a garden center, choose sturdy plants up to 12 inches tall. The plants should have stems at least the diameter of an inner ink pen tube and the leaves should be closely spaced up the stem. Do not buy plants with spots on their leaves, which could increase the chance of diseases in your garden.

Choosing Pepper Varieties

Peppers can be categorized by maturity class, including early, mid-season or late, fruit types, such as cherry, bell, wax, pimiento, paprika, cayenne and jalapeño, fruit color, such as green, red, yellow, orange and purple, or pungency, including non-pungent, mildly, moderate or highly pungent.

Check the days to maturity or days to harvest estimates in the seed or plant description. Look for peppers described as widely adapted and cold tolerant. Some seed catalogs will classify their offerings. 

In general, smaller-fruited peppers are more tolerant of both cool and hot temperatures, so while you may enjoy the challenge of growing big bell peppers, planting some smaller sweet peppers will result in a more satisfying harvest.

Varieties for West Virginia

Starting Seeds

Peppers can be grown from seed or transplants, but in West Virginia, direct-seeding peppers is not recommended. Transplanting is much easier.

Start pepper seeds indoors about eight weeks before planting outside. This is earlier than you would normally start tomato seeds. If starting seeds indoors, see the WVU Extension Garden Calendar for more information.

Plant seeds 1/4 inch deep in flats containing sterile, soilless germination mix.

Use a heating mat to keep the flat at 80 to 90 degrees until seedlings emerge. Be sure to monitor potting mix moisture, as heating mats will dry the mix out faster. 

Once seedlings emerge, a soil temperature of 70 degrees is ideal. Warm soil is better than cool. Provide bright overhead light for the seedlings.

Thin or transplant seedlings after true leaves appear so that seedlings are 2 to 3 inches apart. Without enough bright light directly overhead, the stems of the little plants will elongate and lean over.

Pepper plants may start to flower while still indoors. Pinch off the clusters of flower buds until just before you plant to put the plants out in the garden.

Reduce watering when plants are 4 to 5 inches tall and six to eight weeks old. Place plants outside where they will receive wind protection and a couple hours of sunlight. Gradually expose them to more sunlight over the next week or two, bringing them indoors if night temperatures drop below 55 degrees.

Transplanting

Location

• Choose a location in your garden where you have not grown tomatoes, potatoes, peppers, eggplants and tomatillos for the past three or four years.
• Space pepper plants 15 to 18 inches apart in rows 30 to 36 inches wide.

Climate

• Transplant outdoors after nighttime low temperatures are above 50 degrees.
• Dry soil, daytime temperatures above 90 degrees, or nighttime temperatures below 60 degrees or above 70 degrees can weaken plant growth.
• Transplant in late afternoon or on a cloudy, calm day.
• Pepper flavor is best when the season has been warm and sunny. Fruit that matures under cool or cloudy conditions will not be as tasty.
• Fruits are vulnerable to sunburn. They develop white patches if there is not enough leaf surface to cover fruit and protect them from sunlight during hot, dry weather.

Treatment

• Water plants well before transplanting.
• Transplant seedlings grown in separate containers without disturbing the roots.
• When transplanting seedlings in peat pots, do not expose the top edge of the peat pot above the soil surface, or the peat pot will act like a wick and rapidly draw the moisture from the root ball, stressing the plant.
• Set pepper seedlings out in the garden so that the shoots are at the soil line as they were before transplanting.
• With a hand shovel, make a hole large enough for the root ball of the transplant.
• Firm the soil around the roots and water the transplant.

Keeping Plants Healthy and Productive 

Irrigation

Water peppers deeply and frequently, applying 1 to 2 inches per week. Use drip irrigation if possible. Mulching around the plant will conserve soil moisture and reduce weed growth. Irrigate so that moisture goes deeply into the soil. Irregular watering (over or under) can cause flower drop or blossom-end rot, a dark leathery spot on the bottom of the fruit.

Water

• Consistent soil moisture levels produce the best quality fruit. Poor soil moisture levels weaken flowers and small fruits, and peppers are vulnerable to blossom-end rot.
• Avoid overhead sprinkling. Wet leaves are more disease prone. Soil splashed up onto the leaves can contain disease spores.
• A light sprinkling that just wets the surface of the soil can cause shallow root development, increase the crop’s vulnerability to hot weather and drought stress, and reduce fruit quality.
• If the plant does not receive one inch of rain weekly, soak the soil thoroughly at least once a week.
• If your soil is sandy, it is important to water more often than once a week.

Fertilization

Avoid heavy fertilization of peppers which encourages excessive foliage growth and delays flowering and fruit maturity. Side-dress the rows with nitrogen, using 1/4 tablespoon per plant at four and eight weeks after transplanting. Place the fertilizer 6 inches to the side of the plant and irrigate into the soil.

Staking

Peppers, especially bell peppers, should be staked to prevent stem breakage and reduce sunscald.

Problems

Plastic and organic mulches effectively control weeds. Higher density plant spacing will also smother weeds. Shallow cultivation will help avoid root damage especially around young plants. Aphids, flea beetles, hornworms, virus and sunscald are common issues for peppers. Bacterial leaf spot is a common disease; choose BLS resistant varieties. Insecticides, nutrient control, watering and removing infected plants are ways to manage these problems.

Controlling weeds

• Frequent, shallow cultivation with a garden hoe or trowel will kill weeds before they become a problem.
• Cultivate just deeply enough to cut the weeds off below the surface of the soil.
• Peppers benefit from black plastic mulch that warms the soil, decreases weed competition and keeps soil moisture.
• Mulching with herbicide-free grass clippings, weed-free straw or other organic material to a depth of 3 to 4 inches can help prevent weed growth, decreasing the need for frequent cultivation.

Insects

• Cutworms chew stems at the soil line, leaving the severed tops uneaten.
• Tomato hornworms can chew holes in the fruit.
• For assistance in diagnosing unknown problems, contact your local WVU Extension office.

Diseases

• Use good cultural control practices, such as crop rotation, to reduce disease problems to a good level and have a successful harvest.
• Many peppers have natural resistance to common diseases. A code printed on the seed packet or plant tag identifies the resistance.
• Verticillium wilt can cause yellowing and wilt.
• Early blight can infect peppers, although this is not common.
• If you start your own plants, start with clean seed. If you buy plants, examine them carefully and reject any that have spots on their leaves, wilting leaves or appear pruned.

Harvest and Storage

Pepper fruits require 35 to 45 days to mature from flowering to full color depending on the temperature and variety. Fruits should be firm, plump and smooth skinned for best flavor and quality. Pick fruits as they mature. At the end of the season, harvest all fruits that are mature green or colored slightly. Peppers will store for one to two weeks if held at 50 to 55 degrees.

Wear gloves when picking hot peppers. Wash your hands after touching hot peppers and before using the bathroom or touching your eyes. Even sweet peppers may contain enough capsaicin to irritate skin. Harvest peppers when they have reached mature size.

Many sweet varieties have good quality when green, as well as when ripened. Use most peppers before ripening. For example, use jalapeños when they are green, and pick Hungarian wax peppers when yellow. You should not ripen either variety until it is red.

Some varieties of pepper bear fruits that will separate easily from the plant. Harvest most peppers by clipping the stem of the fruit with sharp shears. As you continue to harvest, the plants will continue to produce flowers and set more fruit.

Peppers will keep for a week or more in the refrigerator. They are sensitive to the cold, and their skins may become pitted after too long under refrigeration. There are many ways to preserve your pepper harvest.

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Authors: Lewis W. Jett, WVU Extension Specialist – Commercial Horticulture, and Brandy Brabham, WVU Extension Agent – Roane County

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