Horticulture: December 1999

The next time you are grocery shopping, check the prices for specialty (colored) bell peppers. They are anywhere from two to three times as much as green bell peppers. Retail prices as high as $3.00 per pound are not uncommon and are associated primarily with the additional cost (risk) involved in growing specialty peppers.

Most bell pepper fruit are green when immature and red when mature. Red bell pepper fruit have higher concentrations of vitamins A and C, as well as a higher sugar content. Because of increased consumer demand for a more nutritious, flavorful, and attractive fruit, pepper breeders are releasing an increasing number of hybrid varieties that develop a yellow, orange, purple, or chocolate color after maturing.

It takes about forty-five to sixty days from the time a pepper flower is pollinated until the fruit reaches its maximum green size. It takes an additional three weeks for the color to develop. A lot of things can go wrong during that time. There are additional operating expenses, and fruit quality often suffers as a result of harsh growing conditions. Fruit maturing during summer are less dense and have thinner walls. Also sunscald risk to the fruit increases as light intensity increases.

In an effort to beat the heat, we conducted a hoop house trial this spring at our Headquarters Farm Horticulture Center in Ardmore,OK. On March 24 transplants of nine bell pepper cultivars (table 1) were set into four 40-inch-wide beds equipped with dripirrigation and black plastic mulch. Plants were spaced 18 inches apart in the row and between rows, with two rows per bed. Thirty-two plants of each cultivar were used, for a total of 288 plants. Cultivars were placed randomly within the house. Preplant fertilizer was applied according to soil test results. Nitrogen was applied weekly on a schedule developed by the University of Florida.

Harvest began on June 23 and concluded on July 6, by which time pepper quality had diminished so much that continued harvest was unjustifiable. As expected, high temperature was the culprit.

Table 1 summarizes the performance of all nine cultivars. Mandarin exhibited the highest marketable yield and the highest fruit weight. None of the varieties developed a uniform mature color. At the Noble Foundation, most people surveyed about fruit quality considered the multicolored looks appealing.

Additional trials need to be conducted to fine-tune the system. Earlier planting dates and evaluation of early-maturing varieties will be emphasized.