Agronomy

Description

Part of the Solanaceae family, peppers are a warm-season crop botanically related to tomatoes, potatoes and eggplants. USDA recorded that commercial bell pepper production in the southern U.S. began during 1925, but peppers originate from Mexico and Central America. In such warmer climates, peppers are considered perennials. In more temperate climates, such as Missouri, peppers are grown as an annual crop. Plants may grow between 1 foot and 3 feet tall and 1 foot to 3 feet wide.

Pepper varieties differ based on whether they have a pungent or sweet flavor. Because bell peppers don’t express the pungent capsaicin compound, they are classified as sweet peppers. The fresh market consumes most U.S.-produced peppers.

Site Selection

When choosing a pepper production site, note that pepper plants like well-drained, loamy soils. Ideally, the pH level will be between 6.0 and 7.0. To control pest susceptibility, avoid planting peppers in rotations with related crops, such as tomatoes, potatoes and eggplants. In some cases, the same diseases would also afflict these related crops.

Avoiding several other types of sites may also encourage better pepper production success. For example, in low-lying fields near creeks and rivers, the humidity and moisture typical of such areas may increase bacterial spot risk. If fields have residual herbicide levels due to previous corn and soybean rotations, then the residual herbicide may harm pepper plants. Tobacco and pepper fields shouldn’t be near one another because aphid-vectored viruses may spread between the two crops.

The USDA Economic Research Service reports that most U.S.-grown bell peppers originate from fields designed as raised beds that use drip irrigation and mulch. However, producers may also choose to grow peppers in high tunnels, which are greenhouses covered in plastic and heated by the sun. In a high tunnel, producers build raised beds, cover them with plastic mulch, run one or two drip irrigation lines per bed and plant peppers in single or double rows. A high tunnel can protect peppers from temperature, wind, rainfall and pests that could harm their crop. Adding row covers may further protect the plants from frost. Using a high tunnel would also extend the growing season. In a high tunnel, producers may transplant peppers from early April to mid-July, and they can continue harvesting through November. If planting peppers in a high tunnel that measures 2,500 square feet to 3,000 square feet, then producers could grow roughly 700 plants to 800 plants.

Fertility

Producers may apply fertilizers to an entire pepper production field, or they may concentrate these applications on raised beds where plants would be established. Before transplanting pepper plants, apply 80 pounds of actual nitrogen per acre. After transplanting pepper plants, apply a nitrogen and phosphorus starter solution.

During the growing season, plants can benefit from another 50 pounds of nitrogen. The growing season application may be administered using a drip irrigation system, or side dressing pepper plants with nitrogen four weeks following transplanting is an alternative. Minimize high-ammonium nitrogen fertilizer applications. These fertilizers may interfere with calcium absorption, which is essential to control blossom end rot outbreaks. Other fertilizer requirements will depend on soil test results. At most, producers may apply phosphorus at 150 pounds per acre and potassium at 200 pounds per acre.

Variety Selection

The University of Missouri recommends several sweet bell pepper varieties for Missouri growers. The following table summarizes these varieties by listing their names, days to maturity and color. Days to maturity ranges from 56 days to 76 days; this estimate measures the number of days from transplanting. Waiting another 10 days to 14 days would lead to full pepper color development. The color range provides the immature fruit color and mature fruit color. Note that disease susceptibility will vary by variety.

Generally, green bell peppers that continue to mature will turn red. Specialty bell pepper varieties, though, may ripen to other colors such as yellow, orange and brown. Given that colored bell peppers need additional maturation time, producing them requires more expense and may be more difficult. As peppers spend more time maturing on the plant, yield loss risks associated with weather, pests and other uncertainties present a longer term challenge. Generally, colored bell peppers command a premium relative to green bell peppers. The premium may compensate producers for the additional production risk.

Recommended Sweet Bell Pepper Varieties in Missouri

Planting

Pepper seed germinates slowly when planted in field soil, and the seed tends to not germinate evenly. Pepper transplants are a better alternative. To begin transplants, prepare transplant trays or flats with soilless germination media, sow seeds at about a 0.75-inch depth, and provide the seeds with six weeks to nine weeks in a greenhouse setting to sprout and grow. Pepper seed germinates best at temperatures that range from 80 degrees F to 85 degrees F. Plants grow well at temperatures between 70 degrees F and 75 degrees F. If the air temperature drops below 50 degrees F or exceeds 94 degrees F, then pepper flowers may fall, which will limit fruit set.

As a rule of thumb, transplant peppers from two weeks to three weeks following the last typical frost date. By then, the soil temperature has increased, and weather conditions have more stability. An area is well-suited for pepper production when the soil three inches deep has warmed to 60 degrees F.

About one week before transplanting pepper seedlings, reduce fertilization. This will harden off the plants. Reducing the water application would also help to harden pepper plants and minimize shock that they may experience after being transplanted. Exposing seedlings to temperatures from 60 degrees F to 65 degrees F for a few days before transplanting will also help to harden them. After transplanting, growth may suffer in over-hardened plants.

Additionally, pinch off flowers and any small fruit that has developed before planting. By removing flowers and fruit, the pepper plant can concentrate its resources on developing roots and leaves. Per acre, producers generally plant 10,000 to 12,000 pepper plants. Often, pepper growing areas use plastic mulch and drip irrigation.

Cultural Management

Because pepper plants have shallow root systems, supporting heavy fruit can cause them to bend. Constructing a staking system made from wooden or metal stakes and nylon twine can hold the plants, ensure that they keep an upright position and minimize fruit sunscald.

Typically, pepper flowers self-pollinate. However, adding a beehive to the pepper production area may improve pollination and allow pepper plants to yield more fruit.

Water Management

Given that pepper plants have shallow roots, moisture stress may challenge production. Water access would be most critical during transplanting, flowering and fruit setting. If pepper plants experience moisture stress, then flowers and small fruit may drop. Leaf area will also shrink, and this may lead to higher sunscald risk. Without enough water, pepper plants may also have enhanced blossom end rot susceptibility. Using organic mulches may control soil water loss. Too much water, however, may increase disease susceptibility.

Weed Control

If weeds compete with pepper plants, then the plants may yield less, and the peppers that they produce may have inferior quality. To help manage weeds, producers may use mulch. Applying herbicides and adopting a good crop rotation are other strategies to minimize weeds. For planting areas with only a few weeds, cultivation may adequately control the weeds. By managing weeds, producers may also effectively control diseases and pests.

Insects and Diseases

In Missouri, pepper plants may experience damage from insects such as the European corn borer, pepper maggots, aphids, thrips, stink bugs, spider mites and cucumber beetles. To know whether pests present a challenge, consider using insect traps and scouting the area to gauge pesticide application needs.

Multiple diseases may affect peppers. Those diseases include bacterial leaf spot, phytophthora blight, anthracnose and viruses. Disease prevention strategies for peppers include choosing disease-resistant varieties, rotating crops and choosing planting areas that provide air and water infiltration for the soil.

As another disorder that affects sweet peppers, blossom end rot has a link to calcium and moisture availability. Fruit with blossom end rot has a calcium deficiency. When heavy rains follow long dry periods, blossom end rot is common because such conditions limit peppers from absorbing enough calcium. Because calcium availability can influence blossom end rot incidence and fruit quality, producers may consider testing their soils for calcium.

Harvest and Storage

To harvest bell peppers, producers rely on hand labor. They may choose to harvest peppers when fruit has entered its mature green stage. Alternatively, they may harvest peppers a few days later after the peppers have turned color.

By cooling peppers immediately after harvest, producers can minimize quality degradation. Ideally, producers should store peppers in an environment that maintains a 50 degrees F temperature and 95 percent relative humidity level. If temperatures drop below 45 degrees F, then chilling injury presents a risk. Pitting, fruit decay, seed cavity discoloration and fruit softening without water loss may signal that peppers have had chilling injury.

If peppers are exposed to temperatures warmer than 50 degrees F for an extended period, then they may experience color change, decay and drop fresh weight. If stored in the right conditions, then peppers will last for two weeks to three weeks.

Sources

Cantwell, Marita. 2013. Bell Pepper: Recommendations for Maintaining Postharvest Quality. University of California, Davis. Davis, CA 95616.

Cornell University. 2006. Peppers. Cornell University. Ithaca, NY 14850.

Correll, Sabrina and Suzanne Thornsbury. 2013. Commodity Highlight: Bell Peppers. USDA Economic Research Service. Washington, DC 20024-3221.

Kaiser, Cheryl, Matt Ernst and Shawn Wright. 2014. Bell Peppers. University of Kentucky. Lexington, KY 40506.

Orzolek, Michael D., Lynn F. Kime, Steven M. Bogash, Jayson K. Harper and R. Matthew Harsh. 2010. Pepper Production. Penn State Extension. University Park, PA 16802.

Trinklein, David H. 2010. Growing Sweet Peppers in Missouri. University of Missouri Extension. Columbia, MO 65201.