Sweet Peppers in Zone 8B — Pacific Northwest

Sweet peppers are a rewarding addition to any Pacific Northwest garden. Their crisp texture and sweet flavor shine in summer salads and stir-fries. The satisfaction of harvesting colorful peppers you grew yourself, even with our mild summers and cool nights, is unbeatable.

While we might not have the blazing heat some peppers crave, our long, mild fall extends the harvest window. By starting seeds indoors and choosing the right varieties, you can enjoy a bountiful sweet pepper harvest within our 210-day growing season. With careful timing, you can overcome the challenges of our wet springs and still enjoy plenty of delicious peppers.

Starting sweet peppers indoors is essential to get a head start in our climate. Begin your seeds indoors from mid-February through early March, about eight weeks before the last expected frost. This gives them ample time to develop before transplanting outdoors.

Use seed trays with a good quality seed starting mix. Provide consistent bottom watering to avoid damping off and ensure even moisture. Place the trays in a warm location, ideally around 75-80°F, and provide ample light. Our overcast spring days mean supplemental grow lights are almost essential to prevent leggy seedlings.

Transplant your sweet pepper seedlings outdoors from mid-April through mid-May, once the soil has warmed up. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Space your sweet pepper plants 18-24 inches apart in a sunny location. Keep an eye on the weather forecast, as late frosts can still occur in the PNW during this time. Be ready to cover your plants if a cold snap threatens.

Consistent watering is key to growing sweet, thick-walled peppers in our dry summer climate. While we get plenty of rain in the spring, the dry summer months mean you'll need to provide supplemental water. Aim for about 1-2 inches of water per week, depending on the weather.

Use the finger test: stick your finger about 2 inches deep into the soil near the base of the plant. If it feels dry, it's time to water. Water deeply at the base of the plant, rather than overhead, to minimize the risk of fungal diseases in our region, especially late blight.

Pay attention to your plants! Wilting leaves indicate underwatering, while yellowing leaves and soggy soil suggest overwatering. A layer of mulch around the base of the plants helps retain moisture and keeps the soil temperature more consistent.

While not always necessary, providing support for your sweet pepper plants can be beneficial, especially as they become laden with fruit. Bushy varieties can sometimes flop over, especially after a heavy rain. Staking prevents branches from breaking.

Tomato cages work well for supporting sweet peppers, providing all-around support as the plant grows. Install the support at planting time to avoid damaging the roots later. Simply place the cage over the plant and gently guide the branches as they grow.

Pinching off the first few flowers that appear on your sweet pepper plants is a common practice that encourages stronger root development. This results in a more vigorous plant and ultimately, a higher yield of peppers later in the season.

Simply pinch off the flowers as soon as you see them. Otherwise, minimal pruning is needed. As the end of the season approaches (around early November in the PNW), you can remove any remaining small peppers to encourage the plant to put its energy into ripening the larger ones before the first frost.

You can expect your first sweet pepper harvest from late June through mid-August, depending on the variety and when you transplanted. Sweet peppers are ready to harvest when they reach their full size and color for the variety. Remember, they get sweeter the longer they ripen on the plant.

To harvest, use pruning shears or a sharp knife to cut the pepper from the plant, leaving a short stem attached. Avoid pulling the pepper, as this can damage the plant. Regular harvesting encourages continued production.

As the first frost approaches in early November in the PNW, harvest any remaining peppers, even if they are still green. They can ripen indoors in a paper bag with an apple or banana.

Here are some common issues 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.
• What causes it: Temperature stress is the main culprit. Our cool nights or unexpected heat spikes during the day can prevent fruit set.
• How to fix/prevent it: Be patient, as fruit set usually resumes when temperatures moderate. Provide afternoon shade during extreme heat. Ensure consistent watering and avoid over-fertilizing with nitrogen.

Aphids

• What it looks like: Clusters of tiny insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue.
• What causes it: These sap-sucking insects thrive in warm weather.
• How to fix/prevent it: A strong spray of water often knocks them off. Encourage beneficial insects like ladybugs. Insecticidal soap or neem oil can be used for heavier infestations.

Sunscald

• What it looks like: White, papery patches on fruit exposed to direct sun.
• What causes it: Intense, direct sunlight on fruit, usually after leaf loss.
• How to fix/prevent it: Avoid over-pruning foliage. Use shade cloth during heat waves. Ensure healthy foliage to shade fruit naturally.

Blossom End Rot

• What it looks like: Sunken, dark brown or black leathery patch on the bottom of the fruit.
• What causes it: Calcium deficiency caused by inconsistent watering, common with our wet springs followed by dry summers.
• How to fix/prevent it: Water consistently and mulch heavily to maintain even soil moisture.

Pacific Northwest Specific Challenges: Our mild summers and dry-summer humidity mean blossom drop and sunscald are less severe than in hotter climates, but inconsistent watering can still lead to blossom end rot. Late blight, though more common in tomatoes, can also affect peppers, so practice good sanitation and choose resistant varieties if possible. Slugs can be an issue with seedlings, so use slug bait or other control methods early in the season.

Companion planting can help your sweet peppers thrive.

Good companions include tomatoes, which share similar growing requirements, and basil, which is said to repel pests like aphids. Carrots and onions can also deter pests and improve soil health. Spinach provides ground cover, helping to retain moisture and suppress weeds.

Avoid planting fennel near sweet peppers, as it can inhibit their growth. Kohlrabi and other brassicas can also compete for nutrients and attract pests that may also affect your peppers.