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Growing Jalapeño Peppers: How to Plant, Grow, and Harvest Jalapeños | The Old Farmer's Almanac

Jalapeño Peppers

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The more corking (tiny brown lines) on the jalapeño, the hotter it is!

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Pixabay
Botanical Name
Capsicum annuum
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Planting, Growing, and Harvesting Jalapeño Peppers

The Editors
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Do you seek the heat? Chili peppers, including jalapeños, are warm-weather vegetables which are fun to grow (and eat). Learn how to plant, grow harvest jalapeño peppers and hot peppers in your garden. Plus, we’ve added a great video demo showing how it’s done!

About Jalapeño Peppers

The jalapeño is the most popular chili pepper in North America! This medium-size pepper produces deep-green 3-inch fruit that mature to a bright red.

Hot peppers love the sun and grow in temperatures that range from 70 to 90 F (21 to 32 C). They don’t take up a lot of growing space. A half dozen plants should provide a family with peppers all summer long. You can also grow peppers in containers; look for compact varieties.

All chili peppers vary in heat. On the Scoville heat scale, the jalapeño is rated 2,500 to 5,000 units—a “medium-hot” pepper. If you’re interested in growing other hot peppers, you can follow this same guide. It’s fun to grow a variety, especially if you yearn for the burn!

  • Slightly less heat than the jalapeño: sriracha and tabasco
  • Slightly more heat than the jalapeño: serrano pepper
  • Ratchet up the heat: cayenne pepper and Thai chili
  • Buckle down for the hotlist: habanero, ghost pepper (one million units!), and Carolina Reaper (the record holder at 2.4 million!)

Video: How to Plant Chili Peppers

If you’ve never grown chili peppers, it can really help to see how to plant seedlings in pots or outside—as well as how to water, feed, and harvest these red hot fruits! See this video as well as the complete growing guide below.

Planting

Jalapeños need full sun to blossom and set fruit. Choose a sunny place sheltered from the wind. They’re happy up to around 90°F (or 32°C).  Soil should be well-draining and rich in organic matter. In the spring, prepare the soil by working in a 3- to 5-inch layer of compost to a depth of 6 to 10 inches. Read more about preparing soil for planting.

When to Plant Jalapeño Peppers

Note: Many gardeners purchase transplants (small starter plants) from a local nursery garden center because their climate is not hot enough. Others start seeds indoors early, then transplant to their garden. Of course, if you’re in a hot climate (most southern states), just seed them outdoors!

If you are buying transplants, choose plants with green leaves and strong foliage. Avoid any yellowed leaves, sparse foliage, or spindly stems.

  • For those starting seeds, sow indoors 8 to 10 weeks before your last spring frost date under grow lights. You’ll also need heat for seed germination—again, at least 70°F (21°C)—so the seed tray or pots should be on a heat pad. Of course, if you have a greenhouse, that’s the ideal solution. 
  • To transplant (your own seedlings or starter plants from the nursery), wait until the weather has warmed to a daytime temperature of 70 to 75 degrees F. and nighttime temperature above 60 degrees F.

How to Plant Jalapeño Peppers

  • If you’re sowing seeds into trays or containers to plant in the ground later, fill with seed-starting mix that is best for growing chili peppers. (Potting mixes are fine but hold onto moisture a little too well which peppers can’t stand). We recommend mixing a half ordinary all-purpose peat-free potting mix combined with half coir or coco fiber, with a good few handfuls of vermiculite thrown in for good measure.
  • Plant seeds just 1/4 inch deep (you can just cover lightly with seed-starting mix). Water in and keep peppers moist (though never wet). Ensure your seedlings have good airflow and aren’t crowded.
  • Once the seedlings are a good enough size and big enough to outgrow a tray, we will repot them and give them some liquid feed, using half-strength seaweed feed.
  • Note: You can start with a bigger container if you wish to avoid repotting; bigger pots take more potting mix to fill, but they also need less watering. You can also decide to continue to grow your peppers in containers, especially if your region is temperate. But be sure your final container is about 5 gallons—big enough to grow through harvest.
  • About 10 days before transplanting your jalapeño seedlings (or starter plants that you bought) outdoors, begin to harden off to better transition to the outdoors.  Learn how to harden off plants.
  • In cold regions, you can use black plastic mulch to warm the soil prior to planting.
  • Once soil and nighttime temperatures reach at least 60°F (15°C), transplant your seedlings (or purchased starts) outdoors, spacing them 14 to 24 inches apart.
  • In cold climates, you can make slits in the black plastic to plant.
  • Space plants 2 feet apart. Rows should be spaced at least 2 feet apart to provide good air flow.
  • For transplants, dig a planting hole just deep enough to cover the root-ball of the plant and, when you set the plant in the hole, ensure the top of the root-ball is level with the ground surface. Do not plant deeply like tomatoes!
  • A time-release fertilizer can be added to the soil before you backfill it and firm gently around the plant.
  • Water thoroughly and mulch to hold in moisture.

A large group of green jalapeno peppers

Growing
  • Don’t overwater. Chili peppers HATE sitting in the wet. We can’t emphasize that enough. Too much water can disrupt the flow of nutrients around the plant, causing growth problems and weakening plant so they’re vulnerable to attack from pests and diseases. But worst of all, too much water literally waters down the capsaicin in the developing fruits, quashing all those dreams of super-spicy chilies.
  • Let the top inch or two of soil dry out before watering again. We water just enough to keep plants from ticking over; these are plants that thrive in hot, dry conditions after all. You can even let plants wilt a little, especially later in the growth cycle when the fruits are maturing – and don’t water in the hours leading up to harvest if you want spicier fruits.
  • When the first flowers appear, give your pepper plants a tomato feed or a feed that’s high in potassium. (There are also feeds made specifically for pepper plants.) Or, you could also spread fish fertilizer around the base of the plant.

  • Tall varieties—and those that bear a lot of peppers—will need some support. Bamboo sticks or small tomato cages work well.
  • Weed carefully around young plants to avoid disturbing roots.
  • In warmer regions, use shredded leaves, straw, or grass clippings to keep the soil moist and cool during blistering hot weather.

Overwintering Plants

  • Bring container grown jalapeño plants indoors at the end of the season. Place the container in a sunny spot and, with luck, you’ll get more peppers on the plant.
Harvesting
  • Your chili peppers are ready once they have taken on their final color and full size.
  • They’ll be at their spiciest once they’re mature, so resist the urge to pick them before they are ripe. However, the skin of the pepper may grow leathery over time, so harvest when peppers are green if you prefer that classic jalapeño snap.
  • Never tug chili peppers off the plant. Use a sharp knife or pruning shares to cut peppers, leaving a short stem attached to the pepper. 
  • Wear gloves!  And do not not to rub your eyes afterwards!

How to Store Jalapeño Peppers

  • Fresh peppers with a short stem will store longer.
  • Store unwashed jalapeños in a loosely closed plastic bag in the refrigerator.

Drying peppers is another way to store them. Dry the jalapeño peppers and keep them in a dark cool place. Usually, this is done by either air- or oven-drying:

Air-Drying Peppers

  • Wash and dry the peppers. Place on a tray or wire rack in a well ventilated room or put outdoors on dry sunny days. 
  • You can also string the jalapeño peppers on a heavy thread and hang to dry. Space the peppers a few inches apart and hang in direct sunlight.
  • It will take a couple of weeks for the peppers to dry with this method.

Oven-Drying Peppers

  • Wash and dry the jalapeños. Cut in half and place on a baking sheet. Bake at low heat (100° to 130°F), turning the peppers occasionally. It may take several hours before the jalapeños are dry.
Wit and Wisdom
  • Avoid planting jalapeño peppers in places where you’ve recently grown other members of the nightshade family—such as tomatoes, potatoes, or eggplants—as this can expose peppers to shared diseases.
  • Many people swear by placing match heads in the planting hole to add sulfur.
  • The jalapeño pepper is named for the town of Jalapa in Mexico.
  • Chipotles are mature jalapeños which have been smoked and much of their moisture removed. 
  • Jalapeños seeds are called “picante” and are used as a spice.
Pests/Diseases

On the note of pests, be meticulous with peppers and check regularly. One way to keep tabs on pest populations is to hang yellow sticky traps. You can buy these or make your own by slathering petroleum jelly onto squares of yellow card and then hanging them up among your plants. Encourage natural predators such as parasitic wasps and ladybugs.

Especially look out late in the season for the spider mite, mentioned below, which thrives in the warm, dry conditions chili peppers love.

Jalapeño Pepper Pests and Diseases

Pest/Disease Type Symptoms Control/Prevention
Anthracnose Fungus Yellow/brown/purple/black spots on leaves; sunken, dark spots on stems and fruit; spots may develop a salmon-pink, gelatinous mass; eventually, plants rot Destroy infected plants; choose resistant varieties; provide good drainage; avoid overhead watering; apply compost for nutrition; use mulch; practice crop rotation.
Aphids  Insect Misshapen/yellow leaves; distorted flowers/fruit; sticky “honeydew” (excrement produced by aphids); sooty, black mold that forms on honeydew; large presence of ants on plants Grow companion plants to either attract aphids away (nasturtiums) or repel them outright (basil, rosemary, strong-scented plants); knock aphids off plants with water spray, apply insecticidal soap; put banana or orange peel around plants; wipe leaves with a 1-2% solution of liquid dish soap and water every 2-3 days for 2 weeks; add native plants to attract aphid predators.
Bacterial leaf spot Bacteria Varies; water- soaked rust/black leaf spots between veins later dry/fall out, leaving holes; leaves yellow/ distort/wilt/die; stem cankers Destroy infected parts/ severely infected plants (do not compost); remove plant debris regularly; disinfect tools; prevent plant stress/injury; good air circulation; avoid overhead watering
Blossom-end rot Disorder Caused by lack of sufficient calcium uptake.
Symptoms: dark, water-soaked spots on blossom end of fruit (the side opposite the stem) may enlarge and become sunken, leathery, rotted
Remove affected fruit; plant at proper soil temperature; water deeply and evenly; use mulch; maintain proper soil pH (6.5) and nutrient levels; avoid excessive nitrogen; provide good drainage; avoid damaging roots.
Colorado potato beetles Insect Yellow-orange eggs laid in clusters on leaf undersides; larvae and adults chew holes in foliage Remove eggs/larvae/beetles by hand; use straw mulch; weed around plants; use row covers; destroy plant matter at end of season; practice crop rotation
Cucumber mosaic virus Virus Symptoms vary, but may include: stunting; mottled green/yellow/white pattern or ringed spots on leaves/fruit; distorted leaf growth; warts on fruit Often spread by aphids. Destroy infected plants; choose resistant varieties and certified virus-free seed; use row covers; disinfect gardening tools after each use; keep garden weed-free; use mulch.
Flea beetles Insect Numerous tiny holes in leaves (as if they had been hit by a tiny shotgun) Use row covers to physically block flea beetles; mulch heavily; add native plants to attract beneficial insect predators.
Leaf miners Insect Meandering blisters in leaves caused by tunneling larvae Remove infested leaves; weed; use row covers; till soil early in season; rotate plantings
Root-knot nematodes Insect Roots become “knotted” or galled; plants stunted/yellow/wilted Destroy affected plant matter (especially roots); choose resistant varieties; expose soil to sun (solarize); add aged manure/compost; disinfect gardening tools between uses; till soil in autumn; practice crop rotation
Spider mites Insect Fine webbing, pale mottling of leaves; leaf drop
 
Simply mist plants daily to raise the humidity; apply insecticidal soap
Tomato hornworms Insect Chewed leaves (initially toward top of plant); rapid defoliation; black/green excrement; gouged fruit Check undersides of leaves for hornworms, remove by hand and dispose of hornworms. (If you encounter hornworms that have white, ricelike cocoons on their backs, relocate them instead; the cocoons belong to beneficial parasitic wasps.) Till soil in autumn and spring; companion plant with dill/basil/marigolds to attract (and trap) or repel hornworms; spray plants with Bt (Bacillus thuringiensis).

Flower Drop

  • Under extremely hot sun, jalapeño peppers may drop their flowers. 
  • Too much sun may also cause sunscald on the pepper fruits themselves. The fruit won’t fully develop or may get tannish spots. (This is essentially a sunburn!) 
  • Protect the plants with a sun shade or move the peppers into a cooler spot if they are in containers. 
Cooking Notes
  • Be cautious when handling jalapeño peppers; wear gloves and don’t touch your eyes!
  • The oil that gives hot peppers their kick is called capsaicin. It is most concentrated in the white membranes and seeds inside the fruit.

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