Pepper

Production practices are generally similar to those for tomatoes. Peppers need a fertile, well-drained soil and prefer loams or sandy loams and grow best in a soil with pH 5.5 to 6.8. See Soil Management for a description of types of liming materials and their effect on soil pH, Ca and Mg availability.

Harvesting one ton of peppers removes 3 pounds N, 10 pounds P2O5, and 6 pounds K2O from the soil. The table below lists nutrient recommendations based on soil test results. Pepper is a long-season crop. N uptake increases in the last two-thirds of the season and potassium is critical for fruit development, so in a sandy soil where leaching is likely, it is usually advisable to divide N, and possibly K, into several applications. This will also reduce the possibility of excessive N before and during fruit set, which encourages vegetative rather than reproductive growth. If high capsaicin content is desired in hot peppers, however, N levels during fruit development should be kept to a minimum.

Planting

Because of slow and erratic germination at low temperatures, peppers are usually transplanted. Even under optimal conditions, pepper seeds germinate more slowly than seeds of tomatoes or eggplants. Recently, seed companies have begun offering pepper seeds which have been 'primed' to improve the speed and uniformity of germination. Purchase of such seed can be advantageous both for direct seeding and growing transplants.

Transplant production. Using new seed is important, as pepper seed has a relatively short shelflife. Bacterial leaf spot is a serious problem throughout the South and can often be traced to infected transplants. Even certified disease-free seed should be disinfected by agitating seeds in a 1:4 bleach solution for 40 minutes. The seeds should then be rinsed in clean water and dried. If bacterial spot still appears in the seedlings, plants can be sprayed with streptomycin sulfate 17 WP, plus a copper fungicide. Compared to other crops, pepper seeds require high soil temperatures (75 to 80 degrees F), and low soil moisture for germination. The soil should be only slightly moist until germination. Off-types may need to be rouged out and discarded. Crowding of transplants leads to tall, spindly plants. Eight weeks is the average amount of time needed to grow bell pepper transplants. Other types of peppers generally require only 6 weeks.

Pepper nutrient recommendations based on soil tests.

Traditionally, pepper transplants have been grown directly in the soil either in greenhouses or outdoors in warm areas for shipment north. For production transplant beds, rotation to non-solanaceous crops is critical. Soils with a history of southern stem blight should not be used. If such soils must be used, solarization and keeping soil off the plant stems may offer some protection. As black plastic and drip irrigation are used to increase yields, demand has risen for higher quality transplants, such as those grown in containers.

Container-grown transplants must be put directly in the transplant water in bare ground culture or the dry soil will 'wick' moisture away from the plant. Recently, Florida growers have been urged to plant pepper seedlings more deeply up to the seed or cotyledonary leaves rather than just to the top of the root ball. This technique would reduce problems with wicking, and also appears to reduce wind damage in the first 30 days after transplanting, and to increase early yields. Certainly, 'leggy' seedlings can be planted more deeply than the top of the roots. Containerized plants may be hardened prior to transplanting by increasing ventilation, but enough water should be applied just before transplanting to hold the media together.

Field planting. Recommended spacing for peppers is 3-to-3.5-foot rows with plants 12 inches apart in the row for bell peppers and 18 to 24 inches apart in the row for pimiento peppers.

Peppers should be planted after all danger of frost is past. Row covers are sometimes used to warm plants early in the season and protect them from wind damage. Row covers are sheets of non-woven polyester fibers which are draped over the plant row. Although they do not provide much frost protection, row covers can give plants a daily 5 degree F warmer environment, promoting earlier flowering and taller plants in cool weather. It is not clear how, or if, covers should be used in the South except as protection from wind blasting of stems and leaves. Such damage can open the way for disease.

Even in the northeastern states, row covers are most effective in early plantings. In late plantings in Connecticut, row covers delayed ripening of fruit by 8 days and reduced fruit size compared to non-covered peppers. Row covers also must be removed before flowering. In Connecticut, even in the early plantings, row covers left on during flowering promoted vegetative growth and did not increase fruit set. In 1989, production costs were $700 per acre for reusable row covers, and $500 for labor to install and remove them. Their use should be restricted to situations where prices will clearly be higher for early production, which is not always the case in the southern states. Wind protection is valuable, but can also be provided by rye strips.

Use of black plastic mulch and drip irrigation to increase yield, fruit size, and earliness often make economic sense in the southern states. Results with plastic mulch are best when fertilizer is spread in the row 7 to 10 days before planting and the soil is moist at the time plastic is laid. Laying fertilizer and plastic in the fall may be convenient, but in Louisiana, this practice reduced yields by as much as 100 bushels per acre, probably because of nitrogen loss over the winter.

Yield of peppers grown on white plastic mulch was compared with those grown on compost, sod, and bare ground in Florida. Compost consisting of municipal sewage sludge and yard trimmings was placed on top of the beds at several application rates.

Plants grown with any type of mulch yielded more than plants in bare ground plots, but yields were highest on plots mulched with white plastic.

Pepper cultivars with insect and disease resistance

Irrigation

Thoroughly soaking of the soil results in uniform soil moisture and is more effective than frequent light irrigations. Peppers have more drought tolerance in terms of plant survival than eggplants or tomatoes, but still need a good water supply to produce large, tender, thick-walled fruits. Adequate water is also necessary to maintain enough foliage cover to protect fruits from sunscald. Adequate water during fruiting will prevent bitter flavors from developing in sweet peppers, but may reduce the 'hotness' of chili peppers.

Physiological Disorders

Sunscald. Soft, light-colored areas develop on parts of the pepper fruits exposed to direct sunlight. These light areas shrink to a white, papery-textured area which can cover up to one third of the fruit. Sunscald is most severe in periods of high temperatures and where leaf cover has been lost because of disease or insect damage.

Blossom end rot. Inadequate calcium or low pH can cause blossom end rot, especially when coupled with water stress conditions. As in tomatoes and watermelons, blossom end rot usually appears when the fruit is about half-grown The affected areas first may consist of one or more small water-soaked spots, or they may cover half the fruit. These spots soon become dry, light colored and papery. Later, affected areas are attacked by various fungi that grow over the dead tissue, darkening it.