History and heat

Peppers fall into three primary categories: bell peppers, sweet peppers and hot peppers. Popular varieties fall into one of these categories or are a cross between them.

Although chili peppers originated in the Americas (primarily South and Central) more than 6,000 years ago, they are now cultivated and grown all over the world.

Capsaicin is the chemical in a chili pepper that gives it its heat. Capsaicin is the primary ingredient in pepper spray. The heat in peppers is measured in Scoville heat units (SHU), which is the number of times a chili extract must be diluted in water in order for it to lose its heat. Bell peppers rank 0 on the SHU scale. Jalapeños range from 3,000 to 6,000 SHU. And the hottest chili in the world, according to New Mexico State University's Chile Pepper Institute, is the Bhut Jolokia (from India), measuring a fire-breathing 1,001,304 Scoville units!

Many uses

Most peppers are grown for their culinary qualities, some are grown for medicinal purposes and still others are grown just for their looks.

Chilies are important staples in cuisine from around the world. Not only are they used in many Mexican and Asian dishes, they are also key ingredients in foods from Italy, Hungary, Japan, South America, Turkey, Tunisia and the U.S. Southwest. Indian cooking uses chilies in everything from snacks to curries, to condiments, dips and sauces. In Japan, Korea and the Philippines, even the leaves of the plants are cooked as greens and or in soups.

Chilies don't just spice up your food; they also have been found to help reduce inflammation, provide relief from sinus congestion, reduce cholesterol, prevent ulcers and help fight certain causes of stroke and heart attacks.

In some areas of India, chilies are used to ward off evil spirits. Farmers in parts of Africa lay rows of chilies on the fences surrounding their crops and structures to fend off elephants, who are repelled by the smell of the peppers.

What grows well here

According to one of our local chili experts, Master Gardener Jim Maley, some of the easiest peppers to grow here are the serrano, jalapeño and cayenne. Thai chilies also do well here.

For the sweetest, tastiest bell peppers, Maley recommends letting them fully mature to their red, yellow or orange color, versus harvesting while they are green.

Salsa favorites include habaneros, jalapeños or serranos in their immature green stage, or the bright red Sparky, which is also good for making hot jam, pickles or poppers. The coveted "Pimiento de Padron" is excellent for frying. And "Piment d'Espelette" is one of the best for making into a powder.

Although all chili peppers are technically perennial, a couple of tried-and-true varieties that come back year after year are "Rocoto Manzano" and the "American Chiltepin."

Are you just as interested in looks as in taste? One of the prettiest chilies I have ever grown is the "Numex Twilight," an absolutely stunning plant loaded with yellow, orange, red and deep purple fruit all at the same time.

Other great ornamental varieties include "Marbles," which aptly describes the marble-size fruit that progresses from yellow, to purple, then orange and finally matures into flame red. The unique "Black Pearl" has black leaves, black stems and white flowers. It is covered with shiny black fruit that mature to dark red.

Cultivation tips

Peppers do best if they are planted after nighttime temperatures reach the mid-50s. When you are ready to plant your peppers, soak them in a bucket of water to make sure the root ball is thoroughly wet. If the plant is root-bound, gently tear the mass of white roots apart with your hand or a sharp knife.

If planting in the ground, space the peppers about 10-12 inches apart. For peppers that produce large-sized fruit, planting two peppers per hole will allow them to support each other and produce a dense leaf cover; this will reduce sunburn by providing additional shade. Sunburn isn't as big a problem for peppers with smaller fruit, so just plant them one per hole for those.

Some varieties grow quite large and may need to be staked; small tomato cages work as well. To get the biggest bang out of your peppers, it's important to pick them when they are the right size and color. Make sure to label as you plant and make yourself harvesting notes.

For best fruit production, especially on peppers with larger pods, pick off all flowers and fruit for the first three to six weeks after planting. This is hard to do, but the "tough love" will result in deeper root growth and more foliage on the plant before the fruiting starts.

Peppers need a good bit of water, especially if you are planting in containers.

Water pots every other day for the first few weeks. Watering by hand in the early growing stage is recommended to ensure that you thoroughly soak the potting soil. When planting in containers, mix in organic compost and slow-release fertilizer.

Peppers and chilies need nitrogen for leaf growth. Feed the plants about once a month using an organic, general-purpose vegetable fertilizer. Follow directions on the box and be sure to keep the fertilizer about four inches away from the stem of the plant.

Once the peppers are established, drip irrigation and soaker hoses work well.

If you have them on timers, be sure to cut back when the weather is cooler and add more time when the weather is hot. Using a moisture meter will help take the guesswork out of watering.

Master Gardener Jim Maley contributed to this column by Master Gardener Rebecca Jepsen. Visit the Master Gardeners Web site at www.mastergardeners.org.

The Santa Clara County Master Gardeners offer advice on weekdays in San Jose and weekly in North County. If you live in San Mateo County, the Master Gardeners have twice-a-week sessions.

San Jose 1553 Berger Drive, Building 1 408-282-3105 Weekdays: 9:30 a.m.-12:30 p.m.

North County 1431 Waverley St., Palo Alto 650-329-1356 Fridays: 1-4 p.m.

San Mateo County 80 Stone Pine Road, Suite 100 Half Moon Bay 650-726-9059, extension 107 Mondays and Thursdays: 9 a.m.-4 p.m.