Pepper, Hot

Capsicum annum et al

Hot peppers are perennial plants in the Solanaceae family, which has 90 genera, and between 2,000-3000 species. Most of the plants in this family originate from Central and South America; while many are ornamental plants, a number of important food crops such as potatoes, tomatoes, and eggplants come from this family. Out of the five domesticated species of hot pepper, the most commonly grown variety is Capsicum annum, which most likely originated from the wild chiltepin, now believed to originate from central-eastern Mexico. Other chile species may have been domesticated in Central and South America, and became a dietary staple as early as in Mayan and Aztec civilizations.

Today, chiles have become an important ingredient in the cuisine of nearly every culture around the world. Chiles can vary widely in form, ranging from tiny 1/2 inch fruits to 12 inch long peppers. A number of domesticated chile varieties were brought north from Mexico by Spanish colonizers, while other varieties were likely spread by birds.

Chiles are consumed in a variety of ways, but always add nutrition and excitement to a dish. With a low water content, they are ideal for drying. Capsaicin, the complex compound that makes chile peppers spicy, is located in the white tissues of the fruit and often in the seeds. It has no flavor or color and is usually more concentrated in smaller pepper varieties. Some hot peppers may be mostly sweet, with just a hint of pungency, while others are wildly hot. As peppers mature, the capsaicin levels increase. Capsaicin has anti-fungal properties which help protect the pepper seeds from disease.

Hot peppers thrive in many areas of California, and generally require less water and nutrients that their sweet pepper relatives. Today, most of the domestic fresh pepper supply is imported from Mexico, despite the ideal growing conditions in many areas of California. Trying growing hot peppers a little closer to home!

Sun/Shade Needs (5)
Watering Needs once Established (3)
Heat Tolerance (4)
Frost (1)
Price (1)

Recommended Varieties/Cultivars

There are five domesticated species of hot pepper; Capsicum annum, Capsicum frutescens, Capiscum chinense, Capsicum pubescens, and Capsicum baccatum. Most types of hot peppers commonly grown by home gardeners belong to the Capsicum annum group. Recommendations are highly personal, and depend on your cooking preferences, favorite flavors, and tolerance of capsaicin.

Despite the misleading name, Capsicum annum varieties can all be grown as perennial plants. Some varieties are mildly pungent (spicy), while others may be intolerably spicy. The most popular types include paprika varieties (not very spicy, usually dried); jalepeños; Anaheim/New Mexico types (mild, versatile, harvested at varying times); wax (especially glossy and often used for pickling); cayenne types (usually dried and made into powder) such as Chile De Arbol; Serrano; Poblano types (dried fruits are called Ancho peppers and plants are often labeled as Ancho/Poblano); and Pasilla Bajio, which is dried into a chilaca chile powder for making mole. Gardeners growing hot peppers for the first time should consider jalepeños, which have a relatively short maturation time, are very versatile, and can be used green or red. Jalafuego is recommended for its high yields. Try growing Padron peppers, a more mild pepper that is harvested green and quickly pan-fried with olive and oil for a delicious appetizer. Though generally mild, about 1 in 20 Padron peppers is hotter and will help keep your dinner guests on their toes. Fish Peppers are a beautiful, variegated jalepeño-like pepper with a more diverse flavor profile.

Capiscum frutescens varieties include Tabasco peppers, which are commonly grown in the Southeast United States to produce hot sauce. Plants in this group are smaller, shrubby, and usually have upright fruits; these varieties are recommended for container gardening. Chiles from this group are frequently used in Ethiopia and other parts of Africa, while in the United States they are more often grown as ornamentals. While GardenZeus doesn't have a particular favorite of this species, varieties include the Piri piri and Thai chiles.

Capsicum chinense varieties, from the Amazonian basin, include the spiciest types of chiles; habenero types, Bhut Jolokia, and the hottest pepper in the world, the Carolina Reaper. Habaneros are often used in Jamaican spice mixes and sauces. Try Chocolate, Orange or Mustard Habaneros for plenty of color and heat in the garden. Fruits are slightly wrinkled, and extremely hot. Rocotillo peppers are shaped like lanterns and are easy to dry.

Capsicum pubescens include varieties of peppers that can thrive in cooler temperatures than most other hot peppers, as they originate from the highlands of Bolivia and Peru. They are not commonly cultivated, and have unique fuzzy leaves, violet flowers, and dark colored seeds. Common varieties include Manzanos and Rocotos. These types are usually eaten fresh, because they have especially thick-walled fruit. They can live up to 15 years and can grow up to 6 feet tall, giving them the common name, Tree pepper.

Capsicum baccatum types are fairly rare in home gardens. The most common type of pepper from this category are the Aji chilies, which have long unique shaped fruit and a smoky flavor and are commonly used in Peruvian cuisine. The Aji limon, Aji amarillo and Aji escabeche are the three most important peppers in Peruvian cooking. Try Aji limon, a pepper used to make a spicy yellow Peruvian salsa, which is extremely spicy and is known for its unique flavor. It is small-framed, expected to grow only about 2 feet tall, and well suited to container gardening. The Capsicum baccatum types are considered to be more difficult to grow than other types: plants often drop their flowers instead of setting fruit, plants grow very tall and leggy, and fruits take a very long time to ripen.

Buying/Selection Tips

In the home garden, hot peppers are usually purchased as transplants or started from seed indoors and then transplanted into the garden. Quality seedlings of pepper varieties known to do well in your area are the easiest option for beginners. When buying transplants, tap the pots, cells, or containers to look at roots. Avoid plants with overgrown, circling, or layered roots at pot edges and bottoms. Look for stocky plants free of flowers and fruit. See The GardenZeus Guide to Buying Vegetable Seedlings for important tips about purchasing pepper and other vegetable seedlings.

Growing from seed provides the home gardener with an almost unlimited range of choices. GardenZeus recommends against seeding peppers directly into garden soil, as pepper seeds can be extremely slow to germinate, especially in cooler temperatures. Pepper seedlings are typically slow growing and can easily succumb to damping off. Sowing seeds indoors helps to ensure plants are strong and healthy by the time conditions are warm enough to plant outside. If starting from seed, purchase fresh seed from a reputable company, as peppers seeds lose their viability quickly. Specialty seed companies offer a multitude of varieties, whereas a local nursery may only offer a few.

Soil Needs/Tip

Peppers prefer fertile, well-drained soil with sufficient calcium, and thrive in soil that is neutral to mildly acidic, with a pH from 6.0 to 6.5. Peppers require sufficient levels of phosphorus for successful fruit production and ample nitrogen to build a solid leaf canopy. While sandy soils are ideal, hot peppers can be productive in heavier clay soils that have excellent soil structure and drainage.

Peppers are heavy feeders that wear out nutrients in soil. Consider incorporating high quality compost into your soil before planting to improve fertility and structure. Avoid growing peppers or their relatives including tomatoes, potatoes, and eggplants in the same place for more than one season every 3 or 4 years to avoid depleting soil and encouraging pests and diseases. This rotation period can be reduced or overcome by skilled and biointensive gardeners who are able to amend soils appropriately for the unique needs of pepper plants in their soils, and create conditions that produce a healthy, living soil ecosystem.

Suitable Microclimate

Consistent with their tropical origins, hot peppers require full, hot sun, and are generally more adapted to extreme heat than sweet peppers. Hotter temperatures result in spicier hot peppers. In general, hotter pepper varieties are also more tolerant of cool, wet weather, though their flavors will not fully develop. Hot peppers are much more immune to sunburn than sweet peppers.

The optimal temperature for growing hot peppers is 75 to 85°F. If the temperature is below 55°F, flowers or fruit may drop, and plant will suffer if temperatures are below 50°F. Plants are usually killed or severely damaged by frost. Flowers may drop if temperatures rise to 90 to 95°F during the day, or above 86°F at night.

Utilize south facing walls and reflective surfaces to increase heat in garden spaces that are not very warm. Do not plant peppers in low areas of your garden where excessive moisture or cold air can gather. Choose a location that is sheltered from wind.

Getting Started

Hot peppers enjoy the warm days of spring and early summer; hot days will help them develop full and robust flavors. If carefully maintained, hot peppers are beautiful plants that provide colorful accents to your garden.

When growing hot peppers, it is crucial to develop a strong healthy plant from the beginning. Ensure that young plants have ample water, fertile soil, and nitrogen to develop plenty of fruit. Proper growth is most important for young plants; without proper care, young peppers will grow slowly, and may not recover before producing a premature crop of fruit.

If you are new to growing hot peppers, purchase transplants for the first few seasons; young peppers are sensitive and slow growing. More advanced gardeners can dazzle their taste buds with the huge array of varieties available from heirloom and open-pollinated seed companies.

If planning to eat peppers fresh, 1 to 2 plants of each variety are sufficient for the household. If planning to dry or preserve peppers, opt for 3 to 4 plants of each.

Watering Tips

Successful hot pepper production requires ample water, as peppers are sensitive to water stress in all stages of their life. Drought stress can impact flavor and reduce the yield of pepper plants. Overall, hot peppers require less water than large, succulent sweet peppers. To minimize the possibility of drought stress, plant peppers before daytime temperatures exceed 80°F; this allows pepper plants to develop a more mature root system for water uptake before hotter weather in summer.

Water peppers deeply, to the full extent of their medium deep root systems. Relative to other garden vegetables, peppers prefer a significant soil dry down before being watered again. Plants that are over-watered are more likely to suffer problems, including soil disease.

As pepper plants mature, provide longer and deeper watering to match the root system of the plant; any moisture stress during blooming or fruiting can led to fruit set problems, blossom end rot, or insufficient plant foliage. Peppers are ideally watered with drip irrigation or another method that delivers water directly to the root zone of the plant.

Planting Method/Tips

If starting from seed, sow pepper seeds in flats with light, well draining soil 10-12 weeks before your target transplanting date. Unlike the seeds of its relative, the tomato, pepper seeds are notoriously slow to germinate. Optimal germination temperature for peppers is from 70-85°. This relatively warm temperature range can be difficult to maintain; to maximize your success with germinating pepper seeds in flats, GardenZeus recommends using grow mats or other sources of bottom heat.

Provide young seedlings with good drainage and air circulation, or they may easily succumb to damping off fungus. Clean propagation materials are important for starting peppers; GardenZeus recommends avoiding wooden flats, as they may be more likely to harbor pathogens.

Compared to other vegetable seeds, pepper seedlings require more of a dry-down. Water pepper seeds when the surface of the soil has dried but still sticks to your finger just below the surface. Once germinated, water pepper seedlings when the soil surface is completely dry, and the soil just below the surface is slightly dry.

Hardening off is highly recommended for pepper seedlings, as they often grow slowly. Harden your plants off gradually over a period of 3 weeks, exposing them to outdoor conditions for longer and longer periods. This allows the plants to build strong good structure and to thicken the cell walls in their stems and leaves. Additionally, it allows them to build extra food reserves before they are transplanted; these food reserves are used for building new root tips after planting.

Transplants should be large, well developed plants. Whether you are transplanting seedlings you have grown yourself or you are transplanting purchased starts, minimize shock by transplanting peppers when daytime temperatures are around 65°F and nighttime temperatures are above 55°F. Plant seedlings 1-2 feet apart, depending on the variety. Though rare, peppers can develop adventitious roots; if peppers are leggy, plant seedlings slightly deeper (about an inch) than in their original pot to encourage more roots from the stem.

Spacing

Sow seeds indoors, 1/4 inch deep in flats, pots or cell packs,

If using flats or pots for later transplanting, space pepper seeds 1 inch apart. If using cell packs for later transplanting, place one to three seeds in each section. Select strongest seedlings for later transplanting.

Space transplants 1 ½ feet apart from plant center to plant center. Plant rows 2 feet apart. If area is exposed to wind, place supports in ground before transplanting.

Timelines

7 to 28 days to seed germination at temperatures from 70 to 95 degrees; seeds will not germinate below 55 degrees.
8 to 10 weeks from germination to transplant.
120 to 169 days from germination to harvest, depending on variety and growing conditions.

Pollination Needs/Tips

Peppers produce perfect flowers that are generally self-pollinating, which means that little effort or concern is usually needed from gardeners for pepper pollination. Gently shaking stems with blossoms once or twice per day may increase pollination.

At extreme temperatures, peppers may do not pollinate well and may drop blossoms.

Interplanting/Companion Planting

Companion plants for pepper include garlic and basil.

Consider interplanting peppers with mid size sunflowers. Sunflowers and peppers have similar watering requirements: both prefer deep, infrequent waterings with dry down between waterings. Sunflowers may provide shade to peppers, reducing the possibility of sunburn to pepper fruits.

Nutrient/Amendment/Fertilization Needs/Tips

Peppers perform best in rich, living soil with sufficient organic matter and plenty of calcium. Early in the growing season crush or grind up eggshells, scatter at the base of each plant, and cover with fine mulch, to provide extra calcium to each pepper plant.

Avoid high nitrogen fertilizers, which will create large leafy plants with few or no fruits
To produce high quantities of food and to protect fruits from sunburn, it is important to encourage the early development of a full leaf canopy. To encourage development of a healthy canopy, Garden Zeus recommends adding nitrogen in the form of diluted urea or a cup of chicken manure diluted in 4 gallons of water (half cup if fresh manure) and mixed thoroughly, applied as a soil drench twice a month while plants are developing foliage.

Mulching

Use a quarter to half-inch fine mulch for small starts under four inches in height; increase to an inch or more of fine to medium mulch after plants are 1 to 2 feet tall.

Pruning/Cutting Back/Pinching/Separating

Before pepper plants reach 18 inches in height, encourage the development of roots and foliage by removing blossoms. Remove any damaged or yellowing leaves.

Peppers generally do not require pruning, but advanced gardeners may prune young plants to encourage a fuller leaf canopy.

Peppers grown as perennials need refreshing between seasons. Cut back deadwood and any stems that look raggedy or that hang on the ground.

Propagating

From seed. GardenZeus recommends open-pollinated, untreated, organically grown seeds. (See Garden Zeus section on Planting Method/Tips).

Hot pepper flowers are self-fertile and self-pollinating. If you want to save seeds from your hot pepper plants you must ensure seed purity: different varieties must be at least 500 feet from each other. While self-fertile, hot pepper flowers can be cross pollinated by sweat bees and honey bees. Hot peppers grown next to sweet peppers can result in sweet peppers with seeds that will produce spicy peppers. Select fully mature, disease free fruit from which to save deeds. Protect yourself from the capsaicin when removing the seeds by using gloves or other protective coverings. Dry seeds out of direct sunlight until completely brittle; they should snap when folded in half.

Container Gardening

Hot peppers make excellent container plants. Containers allow you to move peppers to follow seasonal changes in sun, to shaded areas during hot summers, warmer areas during winter, and to protected areas when necessary in response to winds or other environmental factors. Fruits may crack or develop blossom end rot easily as soil dries out quickly in containers, especially during warm-to-hot weather, so pay extra attention to irrigation or manual watering when growing peppers in containers.

Grow peppers in a container that is at least 5 gallons in size, with well-draining, light, fertile soil. Peppers from the Capsicum frutescens group are popular for growing in containers; they provide many small fruits on a plant that is usually bushy and compact. Try growing Thai pepper varieties; they are colorful and produce abundantly. Other varieties recommended for containers include Tunisian Baklouit, Patio Fire, or Fish Pepper.

Seasonal Care

Set out hot peppers transplants in the spring once temperatures have warmed to 75 to 80° for a growing season until nighttime temperatures dip below 50°F.

Allow sufficient soil dry-down between irrigations. More than any other crop, peppers thrive when the soil has a chance to dry-down between waterings. If new leaves show signs of curling or appear wrinkled, it is an indication of a lack of calcium. Amend soil with crushed eggshells or water with a diluted solution of Epsom salts (magnesium) to help make existing calcium in soils more available to plants.

Provide shade cloth if temperatures are climbing into the mid nineties, especially for fruiting plants. High temperatures above around 95°F cause pepper flowers to abort and drop.

Thin early fruits to encourage the plant to produce a larger, healthy plant with more foliage before producing fruit.

As perennial plants, peppers can be carefully removed from the garden, repotted, and brought inside for the winter.

If not growing as a perennial, remove plants and debris at the end of the season and compost the biomass.

How to Harvest

Though generally picked when red and at their peak of flavor and spiciness, hot peppers can be harvested at a variety of stages. Jalepenos are harvested when green, as well as some Poblano types. Peppers should be ripened to maturity on the plant; they will not hold on the plant once mature.

Harvest hot peppers with pruning shears or scissors. Leave a 1/4 to 1/2 inch stem on fruit when possible; the stem helps to lengthen the shelf life of pepper fruits and makes it more difficult for fungi and bacteria to enter the fruit.

Harvesting Tips

To help encourage the plant to continue fruiting, harvest pepper plants as soon as peppers mature. If not growing pepper as a perennial, remove plants and debris at the end of the season and compost the biomass.

If drying pepper fruits, dry only freshly picked peppers with stems intact, free of blemishes. Older peppers may develop mold instead of drying down properly.

Hot peppers tolerate high heat but may be slowed and produce poorly in temperatures above 100°F. Peppers are frost sensitive and need warm nights, ideally between 50 and 60°F to grow and fruit well. Harvest aggressively before forecasted summer heat above 90 to 95°F or before cold snaps or first overnight frost in winter.

What Commonly Goes Wrong

Overwatering: One of the most common reasons for the death of pepper plants, overwatering fosters fungal and bacterial diseases, such as root rot.

Blossom drop: Extreme periods of heat (above 90-95° F) or cold below (50-55° F) may cause plants to drop their flowers.

Poor fruit set: High temperatures and wind can cause flowers to drop or fruit set to be aborted. An insufficient leaf canopy may only allow a plant to produce 1 or 2 fruits.

Small or flat fruit with few seeds: This is usually the result of poor pollination.

Blossom End Rot: A common condition in which the end of immature fruits develops brown spots, turns tough or leathery, or hard, inedible areas may form inside the fruits. This is caused by insufficient or unavailable calcium in soil and/or variable soil moisture (drying out between periods of irrigation). Add compost, eggshells, and be diligent in maintaining even soil moisture. Mulch will help retain moisture levels and buffer radical swings in moisture level.

Slow growth, yellowing, lack of vigor, sickliness in plants: These common symptoms may result from overwatering, underwatering, cold weather, compacted soil, alkaline soil, lack of nitrogen, or lack of a key soil nutrient. May also be the result of too much sun, wind, or other environmental and abiotic factors.

Not a Problem

Pre-mature flowering: Young pepper plants often produce fruits and flowers much earlier than desired; remove fruits and flowers, and ensure the plant has adequate nutrients to continue building foliage and plant structure.

Preservation, Storage, and Use

Peppers may be stored fresh, frozen, pickled or dried. Peppers will continue to ripen after being picked. Store peppers at room temperature to encourage ripening. To slow the ripening process, store peppers under cool conditions.

Under ideal storage conditions of 45 to 50° F and 95% relative humidity peppers will store 2 to 3 weeks. When stored at room temperature in something less than 95% relative humidity, peppers will last several days. Peppers produce very low levels of ethylene gas, but are sensitive to ethylene gas, so it is best not to store peppers with ethylene producing fruits or vegetables.

Peppers are among the easiest of vegetables to freeze. Most peppers need not be be cooked or blanched prior to freezing. Simply wash, slice and remove the seeds and ribs. Peppers may be cut into strips or diced and placed in a freezer container.

Peppers can be pickled, but must be safely processed to avoid developing bacteria that cause botulism. GardenZeus recommends utilizing and following information from a reputable source regarding pickling recipes, techniques and temperatures.

And of course, hot peppers are often dried. Depending on how hot you like your dried peppers, consider removing the seeds and the ribs. The ribs have the most capsaicin, and the seeds are in contact with the ribs. Although hot peppers are often seeing drying whole on a rope with twine, GardenZeus believes the safest method is to use a dehydrator and follow the manufacturer's instructions. If you have removed the seeds before drying, consider saving the seeds and using them as seasoning, as either whole seeds or ground powder. Be aware that drying hot peppers concentrates the spicy flavor. Dried hot peppers must not be stored near or exposed to moisture.

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