Hot Pepper Plant Profile

Habanero Chili Peppers
Courtesy of the National Garden Bureau

The group of edible plants labeled hot peppers includes a small number of species and cultivars within the Capsicum genus. Most hot peppers are only slight genetic variations of the sweet bell peppers found in many gardens. Pepper plants are in the Solanaceae (nightshade) family that also includes tomatoes, eggplants, and potatoes. So-called "hot peppers" are not a botanical classification, but rather a group of pepper varieties grouped together by shape and/or heat intensity.

When a man named Wilbur Scoville first devised a means to test the heat of a pepper in 1912, his hottest entry then came in at 20,000 units. At the time, this seemed plenty hot when compared to the Scoville rating of 0 units for a sweet bell pepper. However, decades of plant development have now created peppers with much greater spiciness. Most people regard a modern Halabeno pepper, at 60,000 Scoville units to be incredibly hot, but there are also peppers so hot they earn Scoville ratings in the millions. Such peppers are not grown for food so much as they are for conversation.

Exotic though they may seem, hot peppers have virtually the same cultural requirements as all other species in the Capsicum genus, including sweet bell peppers. They are normally planted as nursery seedlings in the spring after the soil has warmed. From nursery transplants, peppers take 55 to 80 days to produce edible fruit. More exotic forms must be started from seeds started indoors many weeks before the outdoor planting date.

Botanical Name Capsicum spp. (mostly C. annuum)
Common Name Hot pepper, chili pepper, chili
Plant Type Herbaceous perennial; usually grown as an annual
Size 1 to 5 ft.; 1- to 3-ft. spread (depends on variety)
Sun Exposure Full sun
Soil  Rich, moist, well-drained
Soil pH Slightly acidic (6.0 to 6.8)
Native Area Southern North America and northern South America
Hardiness Zones 9 to 11 (usually grown as annuals)
Toxicity Leaves are toxic; fruits may be toxic in large quantities

How to Plant Hot Peppers

Gardeners zones 8 and above with long, warm growing seasons can direct sow peppers once the ground is warm and not too wet. But most hot peppers are either started from seed indoors or purchased as seedlings.

If you start your own hot pepper plants indoors, give them plenty of time to develop. Seed should be started eight to 12 weeks before your last frost date. The seeds can be slow to germinate. The use of a heating pad or some other means of heating the soil will speed germination. However, it will also cause the soil to dry out faster and the seeds will need more frequent watering.

You should see the first sets of true leaves within about six weeks. At that point, you can transplant them into individual pots and continue growing them indoors. Before planting them in the garden, harden off the seedlings, as they are very susceptible to cold temperatures. Wait to transplant in the garden until after all danger of frost and once temperatures remain reliably above 50 degrees Fahrenheit.

Plant the seedlings about 1 inch deeper than they were growing in their pots. The base of the stems will send out small roots, making stronger plants. Space your plants based on their mature size; hot peppers do not mind being a bit crowded.

Pinching off the early shoots will encourage the plant to become bushy and full. Hot peppers tend to set a lot of fruit all at once. While some varieties are sturdy enough to stay upright on their own, staking may be necessary to keep the fruits from resting on the ground.

Hot Pepper Care

Light

Hot peppers require a full-sun location to grow well and produce ripened fruit.

Soil

Hot peppers can adapt to most soil types. They need well-draining soil, so some organic matter should be added. However, the taste will be hotter if the soil is a bit lean and not overly fertilized. A neutral soil pH of about 6.0 to 6.8 is best. A sprinkling of Epsom salts at planting seems to help fruit set, as does crowding the plants in their bed.

Water

Hot peppers need to dry out between waterings, but make sure they get at least 1 inch of water each week. They will drop their flowers if allowed to become drought-stressed. A good layer of mulch around the base of the plant will help conserve soil moisture.

Temperature and Humidity

Peppers need warmth (at least 70 degrees Fahrenheit) to grow and set flowers. However, at extreme temperatures, 90 degrees and over or under 60 degrees, they will drop their blossoms until conditions become more favorable. If the weather remains cool or if it is an especially rainy growing season, it will take longer for hot pepper plants to begin flowering and ripening their fruits.

Peppers do equally well in dry and humid environments, provided soil moisture is maintained.

Fertilizer

Overfeeding will result in leafy plants with few peppers. Add some organic matter before planting to ensure good drainage as well as provide nutrients. You can also give them a dose of balanced fertilizer at planting time and again when the first flowers appear. Many gardeners add a small handful of Epsom salts to the soil at planting time as a magnesium boost.

Are Hot Peppers Toxic?

The leaves and fruits of all peppers contain a chemical called capsaicin, a recognized chemical irritant. While in sweet bell peppers that concentration is relatively low in the fruits, it's another matter for hot peppers. In hot peppers, the concentration of capsaicin in the fruits is quite large; the burning sensation you experience from eating these peppers is actually the toxin at work.

However, there is little danger of true life-threatening poisoning from hot peppers unless you eat very large quantities. But the toxic nature of hot peppers is worth considering before you take pride in being able to eat hot peppers by the handful.

The same chemical is found in the leaves of pepper plants. But because the taste is bitter, it's rare for pets to eat enough pepper leaves or fruit to cause health issues.

Hot Pepper Varieties

It is thought that all peppers, hot and sweet, originally developed from the wild chiltepin pepper of Central America. The most commonly grown modern hot pepper varieties are cultivars of Capsicum annuum, a species that includes cayenne and jalapenos, as well as sweet peppers. In addition to the C. annuum varieties, other hot pepper species include Capsicum baccatum, Capsicum chinense, Capsicum pubescens, Capsicum frutescens.

Some recommended cultivars to grow include:

  • 'Poblano': These pepper fruits are deep green, almost black, and look similar to a bell pepper. It is one of the milder of the hot peppers, with a Scoville rating up to 1,500 units—more interesting than a bell pepper, but far from intimidating.
  • 'Jalapenos': This variety can range up to 8,000 Scoville units, making it considerably milder than cayenne peppers and within the tolerance level of most gardeners. The fruits are up to 3 inches long and can be green, yellow, or red, depending on cultivar.
  • 'Cayenne': Rating up to 50,000 on the Scoville scale, this one is not for the faint-of-heart. The thin fruits are 1 to 2 inches long, and they mature relatively quickly.
  • 'Thai': This pepper has tiny, elongated fruits that pack a Scoville rating of up to 100,000 units.
  • 'Habanero': This variety is still the standard for the hot pepper lover who wants bragging rights. Fruits are 1 to 2 inches long. At the upper end, these peppers can be blazingly hot, up to 350,000 Scoville units. There are now several varieties of Habeneros available.

For most gardeners, this is the upper end for peppers that will be readily edible. Beyond this, hot peppers become literally dangerous—such as the Carolina Reaper pepper, with a Scoville rating of more than 2 million units. Such peppers can badly burn skin and should be considered toxic unless used with great care.

Harvesting

You can keep your plants producing more hot peppers by harvesting regularly once they reach an edible size. Many gardeners like to allow their peppers to fully ripen and change color, but ripe fruits tend to lose some of their heat.

Cut the fruits from the plant; don’t pull. Hot peppers are best used within a few days of harvest. They can also be canned or frozen.

Growing Hot Peppers in Pots

Peppers do fairly well when grown in pots filled with a general-purpose potting mix, provided you keep them well watered. Potted peppers can be brought indoors in the winter, but they will need a sunny window in order to continue producing fruit.

Common Pests and Diseases

Healthy pepper plants don't suffer much from serious pest and disease problems. However, be on the lookout for the following:

  • Aphids and thrips can infest older plants. Symptoms include crinkled or very narrow leaves. These insects can spread viruses, which have no cure. Destroy any infected plants to prevent spreading the disease. 
  • Cutworms can slice off young plants at ground level. Wrapping the base of the plants with foil, toilet paper tubes, or something similar will thwart them. Even toothpicks on either side of the stem will do the trick.
  • Fungal and bacterial leaf spots may occur. Affected parts should be removed and destroyed. Rotate pepper plants to another spot in following years, as pathogens may persist in the soil. Avoid planting peppers in any locations where other nightshades—such as tomatoes or eggplants—have been growing, as these species suffer from many of the same diseases.