Strawberry in Zone 7B — Pacific Northwest

Imagine plump, juicy strawberries bursting with flavor, grown right in your own backyard. Strawberries are a rewarding addition to any Pacific Northwest garden, offering delicious fruit for snacking, jams, and desserts. The cool nights here actually intensify their sweetness!

While our mild summers and wet springs can present some challenges, with a little planning and attention, you can enjoy a bountiful harvest. Our 193-day growing season gives you ample time to cultivate these delightful berries.

Transplant your strawberry starts outdoors from early to late April, once the soil has warmed up a bit. Before planting, be sure to harden off your transplants by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Space your plants 12-18 inches apart to allow for their spreading growth habit. Keep an eye on the weather forecast during this time; those overcast spring days and occasional showers are typical, but protect your young plants from any unexpected late frosts with row covers.

Strawberries need consistent moisture, especially during fruiting, but they don't like soggy feet. In our dry summer months, aim for about 1 inch of water per week, either from rainfall or irrigation. The finger test is your friend: stick your finger about 2 inches into the soil near the plant; if it feels dry, it's time to water.

Drip irrigation is ideal, as it delivers water directly to the roots and keeps the foliage dry. Overhead watering can encourage fungal diseases in our sometimes humid conditions. Water at the base of the plants to avoid wetting the leaves.

Signs of underwatering include wilting leaves and dry, crumbly soil. Overwatering can lead to root rot and yellowing leaves. A generous layer of mulch, like straw or wood chips, will help retain moisture, suppress weeds, and keep those berries clean.

Strawberries require minimal pruning. Throughout the growing season, remove runners (the long stems that sprout from the main plant) if you want to direct the plant's energy into fruit production. However, if you want to propagate new plants, you can allow the runners to root.

For June-bearing varieties, renovate the beds after harvest by mowing or cutting back the foliage to encourage new growth. As the first frost approaches in late October, remove any dead or diseased leaves to prevent overwintering of pests and diseases.

Your first strawberry harvest should arrive from late June through mid August, about 90 days after transplanting. The best indicator of ripeness is a fully red color with no white shoulders. Ripe berries will also have a fragrant aroma.

Gently pick the berries by pinching the stem just above the green cap, leaving the cap attached to the fruit. Harvesting in the morning, after the dew has dried, will result in the best flavor.

To encourage continued production, harvest frequently as the berries ripen. As the end of the season nears and the first frost threatens in late October, harvest any remaining ripe or nearly ripe berries, even if they're not perfect.

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

Gray Mold

• What it looks like: Fuzzy gray mold on flowers, leaves, and fruit. Berries may rot quickly.
• What causes it: Humid conditions and poor air circulation, common during our wet springs.
• How to fix/prevent it: Ensure good air circulation by spacing plants properly and pruning out crowded foliage. Remove infected plant parts promptly. Avoid overhead watering.

Slugs

• What it looks like: Irregular holes in leaves, especially low-growing plants. Silvery slime trails on leaves and soil. Damage worse at night and in wet weather.
• What causes it: Gastropods that feed at night in moist conditions. Hide under mulch, boards, and debris during the day.
• How to fix/prevent it: Beer traps (shallow dish of beer sunk into soil). Iron phosphate bait (pet-safe). Remove hiding spots. Water in morning so soil surface dries by evening. Copper tape around beds. Diatomaceous earth around plants.

Birds

• What it looks like: Missing or pecked-at berries. Bird droppings on plants.
• What causes it: Birds love ripe strawberries!
• How to fix/prevent it: Netting over the plants is the most effective solution. Shiny deterrents like pie plates or reflective tape may also help.

Strawberry Crown Borer

• What it looks like: Wilting plants, stunted growth, and small holes in the crown of the plant.
• What causes it: Small, white grubs that bore into the crown of the plant and feed on the tissue.
• How to fix/prevent it: Remove and destroy infested plants. Rotate crops to prevent buildup of the pest. Encourage beneficial nematodes in the soil.

Verticillium Wilt

• What it looks like: Lower leaves yellow, wilt, and die, progressing upward. One side of plant may be affected first. Brown streaks in stem cross-section.
• What causes it: Soil-borne fungus that persists for years. Cooler soil temperatures favor it (unlike fusarium). Wide host range.
• How to fix/prevent it: No cure — remove infected plants. Rotate with non-susceptible crops (corn, grains). Solarize soil. Plant resistant varieties (look for 'V' on labels).

Pacific Northwest Specific Challenges: Late blight isn't a direct problem for strawberries, but it can affect nearby tomatoes and potatoes, so be mindful of crop rotation. Cool soil in spring can slow growth, so consider using black plastic mulch to warm the soil. Our short heat in summer means focusing on early- to mid-season strawberry varieties. And finally, slugs are a constant battle in our moist climate, so be vigilant with your control methods.

Strawberries benefit from companion planting. Lettuce and spinach provide ground cover and help retain moisture. Onions and garlic deter pests. Thyme repels strawberry root weevils. Borage attracts beneficial insects and can improve the flavor of the berries.

Avoid planting strawberries near broccoli, cauliflower, pepper, and tomato. These plants can attract pests and diseases that also affect strawberries, and may compete for resources.