How to grow peppers from seed to harvest

Start pepper seeds indoors 8 to 10 weeks before your last spring frost. Hot peppers need 10 to 12 weeks. Keep the seed tray warm, about 80°F (27°C), until the seeds sprout, then grow the seedlings under bright light. Move them outside when nights stay above 55°F (13°C), two weeks or more after your last frost. Give each plant full sun, rich soil, and steady water. Most bell peppers are ready to pick green 60 to 90 days after transplanting. They turn red, yellow, or orange a few weeks later.

Peppers are slow and they love heat. Almost every problem with peppers comes from one of those two facts: a late start, or cold soil and cold nights.

Pepper growing at a glance

Step	Target
Start seeds indoors	8 to 10 weeks before last frost (10 to 12 for hot peppers)
Soil temperature to sprout	80 to 85°F (27 to 29°C)
Days to sprout	7 to 14 for sweet peppers, up to 3 weeks or more for the hottest types
Plant outside	When nights stay above 55°F (13°C) and soil is 65°F (18°C)
Spacing	18 inches (45 cm) apart, rows 24 to 30 inches (60 to 75 cm) apart
Sun	6 to 8 hours or more
Water	1 to 2 inches (2.5 to 5 cm) a week
Harvest	60 to 90 days after transplanting for green bells

Choose the right pepper

Most garden peppers are one species, Capsicum annuum. That includes bell peppers, jalapeños, cayenne, poblanos, shishitos, and banana peppers. Habaneros and Scotch bonnets are Capsicum chinense. They are hotter, slower to sprout, and slower to ripen.

In a short-season garden, small peppers beat big bells. A small fruit sizes up and colors weeks sooner than a big, blocky bell. A few good choices for cool or short summers:

• ‘King of the North’, a bell pepper bred for northern gardens.
• ‘Early Jalapeño’, a jalapeño that ripens ahead of standard types.
• ‘Lunchbox’, a sweet snacking pepper with small fruit.
• ‘Shishito’, a mild frying pepper that bears a big crop.

If your summers are long and hot, you can grow almost anything, including big bells like ‘California Wonder’ and super-hot types.

Start pepper seeds indoors

Use a fresh seed starting mix, not garden soil. Sow seeds 1/4 inch (6 mm) deep, two seeds per cell. Mist the surface and cover the tray with a clear dome.

Heat matters most. Pepper seeds sprout best when the soil sits at 80 to 85°F (27 to 29°C). A seedling heat mat under the tray makes a huge difference. In a cool room without one, seeds can take weeks to come up, or rot first. My post on the best temperature to germinate seeds lists targets for other crops too.

Once the first seedlings show, take off the dome and turn on the lights. Seedlings need 14 to 16 hours of strong light a day. A sunny window is seldom enough in late winter, so the plants stretch and flop. My guide to the best grow lights for seedlings covers what to buy and how high to hang it.

A few more tips for strong seedlings:

• Thin to one plant per cell by snipping the weaker one at the soil line.
• Water from the bottom when the mix feels dry on top.
• Run a small fan nearby, or brush your hand over the tops each day. The movement builds thicker stems.
• Feed with a diluted fertilizer once true leaves appear.
• Move each plant into a 3 to 4 inch (8 to 10 cm) pot once it has two sets of true leaves.

If you need supplies, see my seed starting supplies checklist and my picks for the best seed starting kits. For timing in your area, use my guide on when to start seeds indoors.

Harden off and plant outside

Do not rush peppers into the garden. Cold soil and cold nights stall them, and a stalled pepper can sit for weeks without growing. Wait until nights stay above 55°F (13°C) and the soil has warmed to about 65°F (18°C). My soil temperature chart for vegetables shows how to check.

Harden the plants off over 7 to 10 days. Start with an hour of shade outdoors and add more time and more sun each day. My step-by-step guide on how to harden off seedlings has a full schedule.

Plant each pepper at the same depth it grew in its pot. Space plants about 18 inches (45 cm) apart, in rows 24 to 30 inches (60 to 75 cm) apart. Peppers do well a little close together, because the leaves shade the fruit from sunscald.

In cool climates, lay black plastic or landscape fabric over the bed a week before planting. It warms the soil and gives peppers a faster start.

Sun, soil, and fertilizer

Peppers need at least six to eight hours of direct sun. More is better.

Give them loose, well-drained soil with plenty of compost and a pH between 6.0 and 7.0. Mix compost into the bed before planting.

Limit nitrogen. Too much makes big, leafy plants with few peppers. Use a balanced fertilizer at planting, then side-dress with compost or a vegetable fertilizer when the first fruits set. My post on what NPK means in fertilizer explains the numbers on the bag.

Watering peppers

Give them a deep soak, about 1 to 2 inches (2.5 to 5 cm) a week, at the base of the plant. Steady moisture matters. Soil that swings from soaked to dry causes blossom end rot, the dark, sunken patch on the bottom of the fruit.

Once the soil has warmed, add a layer of straw or shredded leaves to hold moisture in.

Growing peppers in containers

Peppers grow well in pots. Use one plant per 5 gallon (19 L) pot, or larger. Fill it with a quality potting mix, not garden soil. My post on the best potting soil for peppers compares options.

Pots dry out fast in summer heat. Check them every day, and expect to water daily in July and August.

Support the plants

A pepper loaded with fruit can snap at the stem, often after a windy storm. Push a sturdy stake into the soil beside each plant when you plant it, and tie the main stem as it grows. A small tomato cage works too.

Why pepper flowers fall off

Peppers drop their flowers when the weather is outside their comfort zone. That includes nights below 60°F (16°C), days above 90°F (32°C), and warm nights above 75°F (24°C). Drought and too much nitrogen can also cause it.

Most of the time, the fix is patience. Keep watering, and the plant sets fruit again when the weather settles. Peppers pollinate themselves, so hand pollinating is not needed outdoors. Indoors, give the plant a gentle shake when it flowers.

Pests and problems

Aphids are the most common pest. They cluster on new growth and the undersides of leaves. My post on aphids on plants covers how to deal with them.

Sunscald shows up as pale, papery patches on the side of the fruit that faces the sun. It happens when leaves fall off or the plant was pruned too hard. Keep the leaves on.

Good neighbors help too. See my list of companion plants for peppers.

When and how to harvest peppers

You can pick peppers at any size, but they taste best at full size. Green bell peppers are ready when they feel firm and heavy. Leave them on the plant two to three weeks longer and they turn red, yellow, or orange, with a sweeter flavor.

Cut peppers off with pruners or scissors, leaving a short stem. Pulling them by hand can break branches.

Picking green fruit keeps the plant setting more. If you want a big harvest, pick some green early in the season, then let later fruit color up.

Before your first fall frost, pick every pepper on the plant, even small ones. Frost kills pepper plants.

Save seeds and overwinter plants

Peppers are perennials in warm climates. In fall, dig up a favorite plant and cut it back by half. Keep it in a sunny window or under a grow light for winter. It gets a head start next spring.

To grow the same pepper next year, save seeds from open-pollinated types. My guide on how to save pepper seeds shows how.