Sweet Peppers in Zone 7A — Pacific Northwest

Sweet peppers are a fantastic addition to any Pacific Northwest garden. Their crisp, sweet flavor shines in summer salads, stir-fries, and grilled dishes. The satisfaction of harvesting your own colorful peppers after our overcast spring days is especially rewarding.

While our mild summers and cool nights present some challenges for heat-loving crops like peppers, careful timing ensures a successful harvest. With our 183-day growing season, starting seeds indoors and selecting the right varieties will set you up for success.

Starting sweet pepper seeds indoors in early to late March gives them a head start before our soil warms up. Peppers need warm soil to germinate, and our springs can be slow to heat up. Use seed trays or small pots filled with seed-starting mix.

Provide consistent warmth (around 75-80°F) using a heat mat. Place the trays under grow lights, as our spring days can be overcast. Bottom watering is especially helpful to prevent damping off. Simply place the tray in a shallow container of water and allow the soil to absorb moisture from the bottom.

Transplant your sweet pepper seedlings outdoors from early May through early June, once the danger of frost has passed and the soil has warmed. Before transplanting, 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 pepper plants 18-24 inches apart in a sunny spot. Keep an eye on the weather forecast; unexpected late frosts can still occur during this time in the PNW. If frost is predicted, cover your seedlings with row covers or blankets.

Consistent watering is key to growing thick-walled, sweet peppers in our dry summer climate. While our summers are mild, the lack of consistent rainfall means supplemental watering is essential. The flavor of your peppers will improve with steady moisture.

During our wet springs, you may not need to water much after transplanting, but once the dry summer months arrive, check the soil regularly. Use the "finger test" – if the top two inches of soil feel dry, it's time to water. Aim for about 1-2 inches of water per week, depending on rainfall. Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases.

Signs of underwatering include wilting leaves and stunted growth. Overwatering, on the other hand, can lead to yellowing leaves and root rot. Mulching around your pepper plants with straw or wood chips helps retain moisture and suppress weeds, reducing the need for frequent watering.

While not always necessary, providing support for your sweet pepper plants can be beneficial, especially as they become laden with fruit. Some varieties grow quite large and can become top-heavy, leading to broken branches.

Stakes, cages, or trellises all work well. Install the support at planting time to avoid disturbing the roots later on. Gently tie the pepper plants to the support as they grow, using soft twine or plant ties. This will help keep the plants upright and prevent the fruit from touching the soil.

Pinching off the first flowers that appear on your sweet pepper plants is a common practice to encourage stronger establishment and higher overall yields. By removing these early blossoms, you direct the plant's energy towards developing a robust root system and foliage.

Throughout the growing season, remove any yellowing or damaged leaves to improve air circulation. As the first frost approaches in mid- October, you can remove any remaining small peppers to encourage the plant to focus its energy on ripening the larger fruit.

You can expect your first sweet pepper harvest from early July through late August, about 65 days after transplanting. Peppers are ready to harvest when they reach their full size and color for the variety. Remember, sweet peppers 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 piece of stem attached. Regular harvesting encourages continued production. As the first frost approaches in mid- October, harvest any remaining peppers, even if they are still green.

Green peppers can be ripened indoors by placing them in a paper bag with an apple or banana. The ethylene gas emitted by these fruits will help the peppers turn color.

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. Small fruit yellows and drops. Plant looks healthy but produces no fruit.
• What causes it: Temperature stress. Our summers are mild, but occasional heat waves can cause blossom drop. Low humidity and 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. Ensure consistent watering. Gently shake the plants to aid pollination.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapid-reproducing sap-sucking insects. Populations can explode during warmer periods.
• How to fix/prevent it: Strong water spray knocks them off. Encourage ladybugs and lacewings. Use insecticidal soap or neem oil for heavy infestations.

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, usually after leaves are removed or lost.
• How to fix/prevent it: Avoid over-pruning foliage. Use shade cloth during extreme heat. Maintain healthy foliage to shade fruit naturally.

Blossom End Rot

• What it looks like: Sunken, dark brown or black leathery patch on the bottom (blossom end) of fruit.
• What causes it: Calcium deficiency caused by inconsistent watering. Common during our transition from wet springs to dry summers.
• How to fix/prevent it: Water consistently. Mulch heavily to maintain even soil moisture. Remove affected fruit.

Pacific Northwest Specific Challenges: Our mild heat can sometimes lead to slower ripening, so choose varieties with shorter days to maturity. While late blight is more common on tomatoes, it can also affect peppers, so practice good garden hygiene and monitor your plants closely. Slugs are a constant threat in our damp climate, so use slug bait or other control methods to protect your seedlings.

Companion planting can benefit your sweet peppers in the Pacific Northwest. Tomatoes make excellent companions because they share similar growing requirements and can provide some shade during hotter days. Basil is another great choice, as it repels pests like aphids and whiteflies. The aroma from basil is also enhanced by cool nights.

Carrots and onions help deter soil-borne pests, while spinach provides ground cover and helps retain moisture. Avoid planting fennel, kohlrabi, and other brassicas (like cabbage and broccoli) near your peppers, as they can stunt growth or attract pests.