Sweet Peppers in Zone 7B — Pacific Northwest

Sweet peppers are a fantastic addition to any Pacific Northwest garden. Their sweet, crisp flavor shines in summer salads, stir-fries, and grilled dishes, and they're incredibly satisfying to grow yourself. Plus, our cool nights actually enhance their sweetness, making them even more delicious.

While our mild summers and wet springs present some challenges for heat-loving plants like peppers, careful timing and a little extra attention will reward you with a bountiful harvest. With our 193-day growing season, you can absolutely enjoy homegrown sweet peppers.

Starting sweet pepper seeds indoors is essential in the Pacific Northwest to get a head start on our relatively short warm season. Aim to sow your seeds from late February through mid March, about eight weeks before you plan to transplant them outside. This gives them plenty of time to develop before our weather warms up.

Use seed trays or small pots filled with a good quality seed-starting mix. Provide consistent warmth (around 75-80°F) using a heat mat, and ensure they receive plenty of light, either from a sunny south-facing window or, even better, a grow light. Bottom watering is a great way to keep the soil consistently moist without overwatering, which can be a problem during our overcast spring days.

Remember that spring starts slowly here. Be patient and don’t rush the process.

Transplant your sweet pepper seedlings outdoors from late April through late May, after the danger of frost has passed and the soil has warmed up a bit. Before transplanting, it's crucial to harden off your seedlings. This involves gradually exposing them to outdoor conditions for about a week, starting with just an hour or two of sheltered exposure and increasing the time each day.

Space your pepper plants 18-24 inches apart in a sunny spot with well-drained soil. Be mindful of potential late frosts or cool spells that can still occur during this time. Protect your young plants with row covers if necessary.

Consistent watering is key to growing sweet, thick-walled peppers in our Pacific Northwest climate. While our summers are mild, they're also dry, and even short periods of drought stress can impact fruit development. Aim to keep the soil consistently moist, but not waterlogged.

During our wet springs, you may not need to water much at all. However, once the dry summer months arrive, you'll likely need to water your peppers 1-2 times per week, providing about 1 inch of water each time. Use the finger test: stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Water at the base of the plants to avoid wetting the foliage, which can increase the risk of fungal diseases, especially with late blight being a concern in our region.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch around your pepper plants can help retain moisture and regulate soil temperature, which is particularly beneficial in our climate with its cool nights.

While not always necessary, providing support for your sweet pepper plants can be beneficial, especially for varieties that produce heavy yields. As the plants become laden with fruit, they can become top-heavy and prone to breaking, especially during our occasional summer wind gusts.

Staking is a simple and effective method. Insert a sturdy stake near each plant at planting time, and gently tie the main stem to the stake as the plant grows. Tomato cages also work well, providing all-around support. Install the support early, ideally at planting time, to avoid disturbing the roots later.

Pruning sweet peppers isn't strictly necessary, but a little strategic pruning can improve your harvest. Pinch off the first few flower buds that appear on the plant. This encourages the plant to focus its energy on developing a strong root system and leafy growth, leading to higher yields later in the season.

Throughout the summer, you can also remove any yellowing or damaged leaves to improve air circulation and prevent disease. As the end of the season approaches (late October in the PNW), you can pinch off any new flowers that appear. This directs the plant's energy into ripening the existing fruit before the first frost.

You can expect your first sweet pepper harvest from early July through late August, depending on the variety and the weather. Peppers are typically ready to harvest about 65 days after transplanting. Look for peppers that have reached their full size and color for the variety.

Sweet peppers get sweeter the longer they ripen on the plant, so don't be afraid to wait until they're fully colored. To harvest, use sharp pruners or scissors to cut the pepper from the plant, leaving a short piece of stem attached. Be careful not to damage the plant while harvesting.

Continue to harvest regularly throughout the season to encourage continued production. As the first frost approaches in late October, harvest any remaining green peppers. They can be ripened indoors in a paper bag with an apple or banana.

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

Blossom Drop

• What it looks like: Flowers fall off without setting fruit, or small fruit yellows and drops. The plant looks healthy but produces no peppers.
• What causes it: Temperature stress. Our mild summers can still have temperature swings. Cool nights or unexpectedly warm days can prevent fruit set.
• How to fix/prevent it: Be patient; fruit set often resumes when temperatures moderate. Provide afternoon shade during heat waves. Keep plants consistently watered.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue and curled or distorted new growth.
• What causes it: Rapidly reproducing sap-sucking insects that thrive in warm weather.
• How to fix/prevent it: Strong water spray, encourage beneficial insects (ladybugs), insecticidal soap, or neem oil. Avoid excess nitrogen fertilizer.

Sunscald

• What it looks like: White, papery patches on fruit exposed to direct sun. Affected areas may blister and rot.
• What causes it: Intense sunlight on fruit, often after leaves are removed or lost.
• How to fix/prevent it: Don't over-prune foliage. Use shade cloth in extreme heat. Maintain healthy foliage.

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 due to inconsistent watering. Common in dry-summer climates like ours.
• How to fix/prevent it: Water consistently, mulch heavily, avoid over-fertilizing with nitrogen.

Pacific Northwest Specific Challenges: Our mild heat and dry-summer humidity can make peppers more susceptible to blossom drop and blossom end rot. Additionally, late blight, which is common in our region, can affect pepper plants. Monitor your plants regularly and take preventative measures to mitigate these issues.

Companion planting can be a great way to improve the health and productivity of your sweet pepper plants in the Pacific Northwest.

Good companions include:

• Tomatoes: They share similar growing requirements and can provide mutual support.
• Basil: It repels pests like aphids and whiteflies.
• Carrots: Their roots loosen the soil, improving drainage.
• Onions: They deter pests and help prevent fungal diseases.
• Spinach: It provides ground cover, suppressing weeds and retaining moisture.

Avoid planting sweet peppers near:

• Fennel: It inhibits the growth of many plants, including peppers.
• Kohlrabi: It competes for nutrients and can attract pests.
• Brassicas (cabbage, broccoli, cauliflower): They can attract pests that also affect peppers.