Vegetable · Solanaceae
Chili Pepper
Capsicum annuum
Hand it heat, sun, and steady water, and a chili plant hangs heavy with fruit from summer into fall.
Full sun
Every 2–4 days
59–86°F · 15–30°C
70–85 days
Overview
Chili peppers carry their heat right out into the garden. Sitting in the nightshade family beside the tomato, the chili came out of the Americas and now grows on every continent people garden. Handle it as a warm season annual and it does just as well staked in a sunny bed as it does in a pot baking on a hot patio.
The fruit runs a wide range. Some pods stay mild with thick green walls meant for fresh eating, while others land fierce enough that gloves come out at the cutting board. The bite traces to capsaicin, the compound packed into the pale ribs and the seeds, and it's the same compound that stings skin, eyes, and the mouths of most animals.
The plant asks for patience at the start and warmth all the way through. Seeds are slow to wake and the seedlings sulk in cold ground, but hand them full sun, even moisture, and a long warm season and they keep hanging on new fruit right up to frost.
Care
The short version: full sun and steady warmth, with the soil held evenly moist so the bottom of the fruit never rots away. Set them in rich, well drained ground, feed lightly across the season, and never push them out into cold soil.
Light
Chili peppers crave full sun, eight or more hours of it across the day. Cut the light short and the plants stretch leggy, the foliage thins out, and far fewer pods hang on by season's end.
Water
Hold the soil evenly moist, watering deeply to at least 6 inches and capping it with mulch to keep that moisture in. The steadiness counts most through flowering and fruit set, since the dry-then-wet swings are exactly what set off blossom end rot. In a pot or through a heat wave, count on watering every 2 to 4 days.
Soil
Set them in well drained loam or sandy loam worked through with organic matter. They sit happy at a pH between 6.0 and 6.8, leaning slightly acidic, and sharp drainage keeps the roots from sitting in wet ground.
Temperature
Peppers run on warmth, growing best between 59°F and 86°F (15°C to 30°C). Cold soil stalls them at the start, and fruit set stutters once the days run too hot, so it's a long mild stretch that fills the plant out.
Humidity
Average humidity in the 40% to 70% band is plenty, so there's no figure to chase. Airflow weighs more, since crowded, damp leaves draw in the bacterial spots that plague peppers.
Feeding
Feed monthly across the growing season with a balanced vegetable fertilizer. A side-dressing of calcium nitrate about 3 to 4 weeks after transplanting, then again a few weeks on, backs up fruit set, though a soil test beats guessing.
Pruning
Peppers want very little pruning. Feel free to pinch off the first flowers to drive bushier growth and stronger roots, strip away any damaged or diseased leaves, and stake the taller plants so a heavy load of fruit can't tip them over.
Repotting
Run the chili as a one-season plant, started fresh from seed each year. Shift seedlings into roomier pots before they head outside so the roots never wind around, and watch for circling roots or fast wilting as the tell that a young plant has outgrown its cell.
Size & spacing
Most chili plants reach 12 to 35 inches (30 to 90 cm) tall depending on the type, bushing out 12 to 24 inches (30 to 60 cm) wide. Hand each one that much room so air moves through and the leaves dry off.
When to plant
Chili peppers run on heat and won't take a frost. Start the seeds indoors well ahead of the last frost, keep the transplants in until nights hold above about 55°F (13°C), and pull fruit from summer on into fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6 to 8 weeks before the last spring frost
- Plant: After the last frost once night temperatures stay above about 55°F (13°C)
- Harvest: Summer to fall harvest of fruit
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
Most trouble with peppers shows up first on the fruit, the leaves, or the flowers. Spot those early signs and you can move in before a small problem runs through the whole plant. Match what's in front of you below, then act while there's still time to help.
Angular brown leaf spots ringed with yellow
Those angular brown spots edged in yellow are bacterial leaf spot, and it races through wet, splashy conditions and can strip a plant bare. Once a plant is heavily marked there's no curing it, so pull the worst and throw them out. Water down at the base, keep your hands off the foliage while it's wet, and move peppers well away from tomatoes and the rest of the nightshade kin.
Fix:
- Remove and discard heavily infected plants
- Avoid overhead watering and handling plants when wet
- Use copper-based products where appropriate
Dark, sunken patch on the bottom of the fruit
That blossom end rot comes from watering that lurches around, not from a soil short on calcium. Let the ground swing from bone dry to soaked and the plant stops moving calcium up into the swelling fruit. Settle into a steady watering schedule, lay down mulch to hold moisture, and keep the nitrogen light.
Fix:
- Maintain even soil moisture and mulch to buffer drying
- Avoid over-applying nitrogen fertilizer
- Confirm adequate calcium with a soil test and amend if needed
Flowers drop without setting fruit
When the weather turns extreme, the open blossoms let go and fall, with peppers dropping flowers once the days climb past 90°F (32°C) or the nights sink below about 60°F (16°C). The plant behind them stays green and sound. Hold the soil evenly moist, ease back on the nitrogen while it blooms, and the fruit set returns once the weather levels out.
Fix:
- Wait for moderate temperatures, when fruit set usually resumes
- Keep soil evenly moist
- Avoid heavy nitrogen feeding during flowering
Curled leaves with clusters of tiny insects and sticky residue
Those soft green-to-black specks packed along the shoot tips and the undersides of the leaves are aphids, and they leave a sticky film of honeydew where they feed while the foliage curls and warps. Blast them off with a hard jet of water first, and save insecticidal soap or spinosad for the heavy colonies. Lady beetles and lacewings will pick off whatever is left if you give them the chance.
Fix:
- Dislodge colonies with a strong spray of water
- Apply insecticidal soap or spinosad if populations are high
- Encourage natural predators such as lady beetles and lacewings
Toxicity
The fruit is good to eat and a fixture in kitchens the world over, so people have nothing to fear from chilis. The catch is capsaicin, the heat compound, a hard irritant to cats, dogs, and most animals that can leave them with a burning mouth, drooling, and a churning stomach. Birds are the strange exception and feel none of it.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock
Safe for
People · Birds
Cats Mild
Bite into the fruit and a cat ends up with a mouthful of burn. Look for drooling, pawing at the mouth, and possibly some vomiting or loose stool that clears on its own.
Dogs Mild
A dog that chews a pepper meets the same sting, with drooling, a churning stomach, and a rush of thirst. Most come right once the heat dies down and they've gotten a drink.
Horses Caution
Horses seldom go near the spicy fruit, yet the capsaicin would scorch the mouth and irritate the gut just the same, so set the plants where they can't reach.
Rabbits Caution
On a small grazer the heat lands hard. One nibble can leave a rabbit drooling and refusing its food, so keep it from browsing the plant.
Livestock Caution
Goats, sheep, and cattle find the burn unpleasant and tend to pass peppers by, but a curious one that does take a bite of the fruit can end up with an irritated mouth and stomach.
Birds Safe
Birds feel none of the heat. The receptor capsaicin acts on simply isn't there for them, and that gap is the whole mechanism wild peppers use to get birds to carry off and spread the seeds.
People Edible
Chili fruit is a kitchen staple and safe to eat, however hot it runs. Pull on gloves when cutting the fiercest types and keep the cut flesh nowhere near your eyes.
Capsaicin causes painful skin and eye irritation when handling or cutting hot peppers. Wear gloves, avoid touching your eyes or face, and wash hands thoroughly afterward; inhaling fumes from cut peppers can irritate the airways.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
United Kingdom
Animal PoisonLine: 01202 509000 (fee applies)
Australia
Animal Poisons Helpline: 1300 869 738
Varieties
Thousands of chili varieties are out there, but a handful keep turning up in home gardens. These are the ones worth knowing by name and by heat.
Jalapeno
Thick-walled and medium-hot, this one is usually picked while the skin is still green, and it is the first pick for fresh eating and pickling.
Cayenne
The pods are long, slender, and wrinkled, running hotter than a jalapeno, and they dry down into the familiar ground cayenne powder.
Habanero
Shaped like a small lantern and very hot, this pepper belongs to the Capsicum chinense species and carries a clear fruity aroma beneath all that heat.
Thai (bird) pepper
Small and fiercely pungent pods stand upright in clusters on tidy, compact plants.
How to propagate
Chili peppers come up from seed, and the one real trick is handing them enough warmth and a long enough head start indoors.
SeedModerate
Start seed indoors 6 to 8 weeks before the last spring frost · Germinates in roughly 1 to 3 weeks in warm soil (about 80-85°F); transplants are field-ready 6 to 8 weeks after sowing
Peppers come up from seed, but they want steady warmth before they'll move. Sow them indoors 6 to 8 weeks ahead of your last frost, set bottom heat near 80°F to 85°F (27°C to 29°C) with bright light over them, and they break ground in about 1 to 3 weeks. Give the seedlings another 6 to 8 weeks and they're set for the garden, once they've been hardened off and the frost is behind you.
Myths
Chili peppers are deadly poisonous to dogs and cats.
Capsaicin sears, but it doesn't poison the way a real toxin would. Chew a hot pepper and a pet ends up with a sore mouth and a queasy stomach for a stretch, with no lasting damage, and culinary peppers aren't on the ASPCA's classic toxic-plant list.
The heat in chili peppers harms birds.
Birds pick up no capsaicin whatsoever and swallow the fruit without so much as a flinch. That blind spot is the entire design, because wild peppers count on birds to gulp the fruit down and scatter the seeds far and wide.