Overview

Chili (including Bell) peppers belong to the Nightshade family (Solanaceae), genus Capsicum (chilies), and originate in the Americas. A tropical perennial bush, chilies are normally grown as an annual in the United States.

The word Chili comes from the Nahuatl language of the Aztecs meaning Capsicum fruit. Pepper is actually a misnomer because these plants are not related to the Black Pepper of India nor the Szechuan Pepper of Asia.

Chilies were first introduced to Asia by the Portuguese after the year 1492 and have become a standard part of the diet. Some of their appeal is that the capsaicin heat in the chilies is anti-microbial, killing bacteria by the millions and making food without refrigeration safer to eat.

There are five domesticated and 23 wild chili species. Three species are most common in North American grocery stores. Capsicum annuum (a perennial south of the United States) is the most widely domesticated and includes nearly all familiar varieties, among them Bell and Jalapeno. Capsicum chinense (originating in the Amazon basin) includes Habanero and its even hotter cousins. Capsicum frutescens is found in Tabasco sauce. Other species are increasingly available to the home gardener.

The leaves and stems of all Chili plants are poisonous.

Selecting Seedlings and When to Plant

At a nursery, choose large, robust seedlings that do not yet have fruit. While seedlings without blossoms are often recommended as the best choice, plants with blossoms but no fruit are okay as long as you snip off the blossoms as soon as you get home. The plant should still be in a growth mode and not switched to fruit production mode.

If Bell-type peppers are desired, consider the smaller pod 'Carmen Sweet Pepper' which is prolific in high temperatures. Like Bells, Carmens have no heat. Bells often do not set fruit when temperatures are over 90°F but may begin to set fruit once the weather is cool.

Unless the nursery kept them in full sun, harden seedlings off before planting by leaving them out during the day, and then bring them inside next to a sunny window. One hour outside the first day, two hours the second, four hours the third. On the fourth day plant them in the morning. Be sure to water the newly planted seedlings.

Put chili plants in the ground when the danger of frost is past. In case a late frost is predicted, be prepared to surround each plant with Wall O' Water or plastic bottles filled with water. Chilies are badly damaged or killed by frost.

Chili Plant Location

Place chilies in well-draining soil in raised garden beds or pots with bottoms not resting in saucers. Chilies do not like wet toes.

Do not crowd chilies. They should be 18-24" apart in rows 24-36" apart, depending on pod size. In other words, 3-6 square feet is needed per chili plant to at least 2 feet deep. The larger the pod produced by the plant, the more space is required. Bell and Poblano chilies need 6 square feet of space for each plant.

When putting seedlings in the ground, remove the entire pot, whether peat moss or plastic. Peat moss pots do not rot in our dry soil and retard root growth, regardless of claims that roots can grow through them.

Set seedlings in the ground at the same depth that they were in the pot. Do not place their crowns (stem-root junction) above soil level.

Shade new seedlings with 50% shade for the first four days to prevent wilting. After that, provide full sun.

Rotate plants yearly so that the same garden bed does not see nightshade family members more than one year in four. This can be done by dividing the garden into four equal quarters. In any one year, three-fourths of your garden should NOT be growing nightshade plants. Nightshade family members include chilies and Bell peppers, tomatoes, tomatillos, eggplants, potatoes, and golden berries. This will discourage the build-up of soil-borne diseases common to nightshades.

Use containers only for plants that produce small chili pods such as Chiltepins and ornamentals. The roots of large pod plants need more space than a container can provide. If using containers, the sides should be white or a light color to prevent the sun from baking the roots.

Companion Plants

Avoid planting chilies near beans, any cabbage family member, or fennel. The roots of these plants produce chemicals in the soil that stunt or harm chilies or vigorously compete for the same nutrients.

Good nearby companions for chilies are basil, carrot, geraniums, onion, marjoram, oregano, and parsley. Their aromas deter some insect pests. Allow some of the parsley and basil to flower. This will attract hoverflies which prey on aphids. Because aphids prefer them, geraniums in pots are used as a trap crop, sacrificed to protect chilies and other edibles.

Support

Chili plants do best with support. Cylindrical cages with vertical sides made of field fence, or concrete reinforcing mesh, about 19" in diameter and 3 to 4' tall, with 6" long wire spikes on the bottom to anchor them into the soil, are best. Avoid wire supports that are wider at the top than at the bottom. These easily topple over in strong winds.

Concrete reinforcing mesh can also be used like a fence. Attach it, or field fencing, to steel T-posts. Tie vines loosely along the fence. Check the ties periodically to ensure stems are not being constricted.

Sun and Shade in the Chili Pepper Garden

Provide full sun in the morning and 50% afternoon shade. Chilies need 6 hours or more of sunlight. However, always provide at least 50% afternoon shade when temperatures are over 90°F. Growers in Phoenix have reported good success growing chilies on the east side of their houses.

Experiments have shown that seedlings grown in 50% shade until they were allowed to flower had more fruit per plant, a greater mean weight per fruit, and a much greater total weight of fruit per plant.

Soil

Chilies are not particularly sensitive to soil acidity, but best results are obtained in the 6.0 to 6.8 pH range. Soils in valleys often range from pH 7.5 to 8.0. Do not use ammonium sulfate to acidify the soil because this is a high nitrogen fertilizer. For further information, see Soil Preparation.

Watering

Place chilies in raised garden beds or pots with bottoms not resting in saucers. This is the best way to prevent overwatering, especially during heavy rains. Chilies do not like wet toes.

Adjust the frequency and amount of watering to rainfall cycles. Do not water if there has just been a heavy downpour. Make sure the rainfall has penetrated deeply and not just wet the surface. A moisture meter purchased on the Internet can help with this.

Water consistently to avoid blossom end rot.

Use mulch around chili plants to retain soil moisture. During the hottest days of June through August, many plants experience water loss by transpiration [evaporation through their leaves], no matter how wet the ground is. The results are wilting, flower drop, and sometimes even fruit drop. The simplest method of fighting transpiration water loss is to increase the humidity around the plants by wetting thick layers of mulch and by growing in 50% afternoon shade. Chilies are tropical and love high humidity.

For chili plants in containers, use a wider than normal saucer filled with small gravel to the brim. Place the pot on top of the gravel and keep water in the saucer at all times to provide humidity around the leaves. The gravel must keep water from entering the pot from the bottom.

Water soil and mulch, not leaves, to cut down on bacterial and fungal diseases.