Sweet Peppers in Zone 6A — Pacific Northwest

Sweet peppers are a fantastic addition to any Pacific Northwest garden. Their sweet flavor and satisfying crunch are a treat, especially since our cool nights here seem to concentrate their sugars. Plus, they’re incredibly versatile in the kitchen and a joy to harvest from your own backyard.

Growing peppers in our region, with its mild summers, can be a bit of a dance with the weather. But by starting indoors and timing your transplant carefully, you can easily enjoy a bountiful harvest within our 148-day growing season.

Starting sweet pepper seeds indoors in late March through mid April gives them a head start against our cool spring soils. You'll want to provide a warm, bright environment. Use seed trays with a good seed-starting mix, and ensure they have consistent moisture.

Bottom watering is your friend! Set the tray in a shallow dish of water until the top of the soil is moist. This prevents damping off. Place the trays under grow lights or in a very sunny south-facing window, as even our sunniest spring days can be a little overcast.

Remember, our springs here in the PNW are slow to warm up, so patience is key. A heat mat can help speed up germination.

Transplant your sweet pepper seedlings outdoors in late May through late June, once the danger of frost has passed and the soil has warmed up a bit. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. Start with an hour or two of shade and increase the time and sun exposure each day.

Space your pepper plants 18-24 inches apart in a sunny spot. Even though our summers are mild, peppers still need plenty of sun. Be prepared for cool, wet weather after transplanting; row covers can provide extra warmth and protection during those early weeks.

Consistent watering is crucial for sweet peppers, especially during our dry summer months. Aim to keep the soil consistently moist but not waterlogged. The "finger test" is a good way to check: stick your finger about 2 inches into the soil. If it feels dry, it's time to water.

During the peak of summer, when we rarely see rain, give your pepper plants about 1-2 inches of water per week. Water at the base of the plant to avoid wetting the foliage, as this can encourage fungal diseases in our sometimes-humid conditions. While we have dry summers, we also have our share of overcast days!

Wilting leaves can indicate underwatering, while yellowing leaves or stunted growth can signal overwatering. A layer of mulch, like straw or compost, will help retain moisture and keep the soil temperature consistent.

While not always necessary, staking or caging your sweet pepper plants can be beneficial, especially as they become laden with fruit. Some varieties can get quite bushy and top-heavy, and a bit of support prevents branches from breaking.

Install stakes or cages at planting time to avoid disturbing the roots later on. Simply tie the main stem to the stake with soft twine as the plant grows. Cages provide all-around support and are particularly helpful for larger varieties.

Pinching off the first few flowers that appear on your sweet pepper plants can encourage them to focus their energy on vegetative growth early in the season. This will result in stronger, more productive plants in the long run.

Throughout the season, remove any yellowing or dead leaves to improve airflow and prevent disease. As the first frost approaches in early October, you can prune off any small, undeveloped peppers to encourage the plant to put its energy into ripening the larger fruits.

You can expect your first sweet pepper harvest in late July through mid September, about 65 days after transplanting. The peppers are ready to harvest when they have reached their full size and color for the variety. They will also feel firm to the touch.

Sweet peppers get sweeter the longer they ripen on the plant, so don't be afraid to leave them on a little longer. Use sharp pruners or scissors to cut the peppers from the plant, leaving a short stem attached. This prevents damage to the plant and extends the storage life of the peppers.

Continue harvesting regularly to encourage the plant to produce more peppers. As the weather cools in late September and early October, keep an eye on the forecast. If a frost is predicted, harvest any remaining peppers, even if they aren't fully ripe. You can ripen them indoors in a paper bag with an apple or banana.

Here are some common problems you might encounter with sweet peppers in the Pacific Northwest:

Blossom Drop

• What it looks like: Flowers fall off without setting fruit. Small fruit yellows and drops. The plant looks healthy but produces no fruit.
• What causes it: Temperature stress is usually the culprit. Our mild summers can still have temperature swings, and if nights stay above 75°F or days exceed 95°F (rare, but possible), peppers may not set fruit. Low humidity, excess nitrogen, or poor pollination can also contribute.
• How to fix/prevent it: Be patient – fruit set will resume when temperatures moderate. Provide afternoon shade during hotter stretches. Keep plants well-watered and avoid over-fertilizing with nitrogen. Gently shake the plants to encourage pollination.

Aphids

• What it looks like: Clusters of tiny green, black, or white soft-bodied insects on stems and leaf undersides. Sticky honeydew residue and curled or distorted new growth.
• What causes it: These sap-sucking insects reproduce rapidly, especially in warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: A strong spray of water can knock them off. Encourage beneficial insects like ladybugs and lacewings. Use insecticidal soap for heavy infestations, or neem oil, which works systemically. Avoid excess nitrogen fertilizer, as it attracts aphids.

Sunscald

• What it looks like: White, papery patches on fruit exposed to direct sun. Affected areas may blister and become susceptible to rot.
• What causes it: Intense, direct sunlight on fruit, often after leaves are removed or lost to disease, suddenly exposing previously shaded fruit.
• How to fix/prevent it: Avoid over-pruning foliage. Use shade cloth during periods of intense heat. Maintain healthy foliage to shade fruit naturally. If fruit is already exposed, drape a small piece of row cover over it.

Blossom End Rot

• What it looks like: Sunken, dark brown or black leathery patch on the bottom (blossom end) of the fruit. Often affects the first fruits of the season.
• What causes it: Calcium deficiency caused by inconsistent watering. It's not a disease, but a nutrient uptake problem triggered by drought/flood cycles.
• How to fix/prevent it: Water consistently! This is the single most effective fix. Mulch heavily to maintain even soil moisture. Avoid over-fertilizing with nitrogen. Calcium sprays may help marginally. Remove affected fruit.

Pacific Northwest Specific Challenges: Our mild summers and dry-summer climate can present a unique set of challenges. While we don't often experience extreme heat, temperature swings can still cause blossom drop. Consistent watering is essential to prevent blossom end rot, especially during our dry summer months. Late blight is a risk, so choosing resistant varieties and practicing good garden hygiene is important. Slugs can be a problem, especially in wet springs, so use appropriate control measures.

Companion planting can be very helpful for sweet peppers in the Pacific Northwest.

Good companions:

• Tomatoes: They enjoy similar growing conditions and can offer mutual support.
• Basil: Repels pests like aphids and whiteflies, and is said to improve pepper flavor.
• Carrots: Their roots help to aerate the soil.
• Onions: Repel certain pests and deter animals.
• Spinach: Acts as a ground cover, suppressing weeds and helping to retain moisture.

Bad companions:

• Fennel: Inhibits the growth of many plants, including peppers.
• Kohlrabi: Stunts pepper growth.
• Brassicas (cabbage, broccoli, cauliflower): Compete for nutrients and attract pests that can also affect peppers.