Jalapeño Peppers in Zone 6B — Pacific Northwest

Jalapeño peppers are a fantastic addition to any Pacific Northwest garden. Their spicy kick adds flavor to everything from salsas to grilled dishes, and their compact size makes them perfect for smaller gardens or containers. Plus, the cool nights in our region actually enhance their flavor!

While our mild summers can present a challenge for heat-loving plants like jalapeños, careful timing and a few tricks can ensure a bountiful harvest. With our 162-day growing season, starting indoors and providing a little extra care will set you up for success.

Start your jalapeño pepper seeds indoors from mid-March through early April. This gives them about 8 weeks to get a head start before transplanting. Use seed trays or small pots filled with a good seed-starting mix.

Keep the soil consistently moist but not soggy. Bottom watering is a great way to prevent damping-off. Place the trays on a heat mat to maintain a soil temperature around 80°F, and provide plenty of light with grow lights, especially during our overcast spring days.

Transplant your jalapeño pepper seedlings outdoors from mid-May through mid-June, after the last expected frost. Before planting, harden off the seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Choose a sunny spot with well-drained soil and space the plants 14-18 inches apart. Our springs can still bring cool nights, so consider using row covers or cloches for the first few weeks to protect the young plants.

Jalapeño peppers need consistent watering, but overwatering is a common mistake in our climate. During our wet springs, you might not need to water at all, except perhaps container plants under cover. Once our dry summer months arrive, though, you'll need to be more diligent.

Check the soil moisture by sticking your finger about 2 inches deep. If it feels dry, it's time to water. Aim for about 1 inch of water per week, but adjust based on rainfall. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our occasionally humid conditions.

Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch around the base of the plant helps retain moisture and suppress weeds, which is especially helpful during our dry summers.

Although jalapeño peppers have a bushy growth habit, they can become quite heavy with fruit. Providing support is a good idea to prevent branches from breaking.

A single stake placed next to the plant at planting time works well. As the plant grows, gently tie the main stem to the stake with soft twine. This will keep the plant upright and prevent the peppers from touching the soil.

Pinching off the first few flowers that appear on your jalapeño pepper plants can actually encourage stronger growth and more abundant fruit production later in the season. This diverts the plant's energy into developing a strong root system and foliage.

Throughout the growing season, remove any yellowing or damaged leaves. Some gardeners also remove peppers with corking lines if they prefer smoother fruit. As the first frost approaches around early October, you can remove any remaining flowers to encourage the plant to focus on ripening the existing peppers.

You can expect your first harvest of jalapeño peppers from late July through mid-September, about 75 days after transplanting. Jalapeños can be harvested green when they are 3-4 inches long for a milder flavor, or you can wait until they turn red for a sweeter, hotter taste. Corking lines on the pepper indicate maturity.

To harvest, use pruning shears or a sharp knife to cut the pepper from the plant, leaving a short stem attached. Regular harvesting encourages the plant to produce more peppers. As the first frost approaches in early October, harvest all remaining peppers, even the green ones.

Green jalapeños will ripen indoors if stored in a warm, dry place. You can also chop and freeze any excess peppers for later use.

Here are some common issues you might encounter with jalapeño peppers in the Pacific Northwest:

Blossom Drop

• What it looks like: Flowers fall off the plant without setting fruit. Small fruit turns yellow and drops prematurely. The plant itself looks healthy, but produces little to no peppers.
• What causes it: Temperature stress is the main culprit. Even though our summers are mild, we can still have periods of warm nights that stress the plants. Low humidity, excess nitrogen, or poor pollination can also contribute.
• How to fix/prevent it: Be patient; fruit set usually resumes when temperatures moderate. Provide afternoon shade during heat waves. Keep plants well-watered, but avoid over-fertilizing with nitrogen. Hand-pollinate the flowers by gently shaking the plant or using a small brush to transfer pollen.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and the undersides of leaves. Sticky honeydew residue on the foliage. New growth may be curled or distorted.
• What causes it: These sap-sucking insects reproduce rapidly, especially during warm spells. Ant colonies often protect them in exchange for honeydew.
• How to fix/prevent it: A strong spray of water from the hose can knock aphids off the plants. Encourage beneficial insects like ladybugs and lacewings, which are natural predators. Insecticidal soap can be used for heavy infestations. Neem oil is also effective and works systemically. Avoid over-fertilizing with nitrogen, which attracts aphids.

Pepper Maggots

• What it looks like: Small holes in the peppers, often with dark frass (insect droppings) inside. The peppers may become distorted or rot.
• What causes it: Pepper maggots are the larvae of the pepper maggot fly. The flies lay their eggs on the peppers, and the larvae burrow inside to feed.
• How to fix/prevent it: Cover plants with row covers before the flies emerge in late spring to prevent them from laying eggs on the peppers. Remove and destroy any infested peppers. Insecticides are generally not very effective against pepper maggots, as the larvae are protected inside the peppers.

Bacterial Leaf Spot

• What it looks like: Small, circular spots on the leaves, often with a yellow halo. The spots may merge together, causing larger areas of dead tissue.
• What causes it: This fungal disease thrives in warm, humid conditions. It can spread through infected seeds, splashing water, and contaminated tools.
• How to fix/prevent it: Use disease-free seeds. Avoid overhead watering. Improve air circulation by spacing plants properly. Remove and destroy any infected leaves. Copper-based fungicides can help prevent the spread of the disease.

Pacific Northwest Specific Challenges Our mild heat and dry-summer humidity can be both a blessing and a curse for jalapeño peppers. While we avoid the extreme heat that can cause blossom drop in other regions, our cool soil in spring can slow growth. The dry summer months mean we need to be vigilant about watering, but also mean we have fewer issues with fungal diseases compared to more humid climates.

Companion planting can greatly benefit your jalapeño peppers in the Pacific Northwest. Plant tomatoes near your jalapeños, as they enjoy similar growing conditions and can offer mutual support. Basil is another great companion, as it repels pests like aphids and whiteflies while also improving the flavor of the peppers.

Carrots and onions are also good choices, as they deter soil-borne pests and don't compete with the peppers for nutrients. Avoid planting fennel or kohlrabi near your jalapeños, as they can inhibit growth. The strong aroma of fennel can deter beneficial insects, while kohlrabi can compete for resources.