Strawberry in Zone 7A — Pacific Northwest

Strawberries, bursting with sweetness intensified by our cool nights, are a must-grow for any Pacific Northwest gardener. Imagine homemade jam from your own berry patch, or simply enjoying them fresh, still warm from the sun (on one of our mild summer days, of course!). They're surprisingly versatile and rewarding to grow here.

While we might not have the scorching heat some regions do, we can still coax a fantastic strawberry harvest from our gardens. With a bit of attention to our wet springs and potential for late blight, you’ll find that strawberries thrive within our 183-day growing season.

Transplant your strawberry starts outdoors from early to late April. This gives them plenty of time to establish before our mild summer arrives. Before planting, harden off your transplants by gradually exposing them to outdoor conditions for about a week.

Space your strawberry plants 12-18 inches apart, allowing them room to spread. Keep an eye on the weather forecast; a late cold snap can still happen in April, so be ready to cover your new plants if necessary. Buying bare-root plants or potted starts in spring is the way to go in the PNW, as growing from seed can be quite slow.

Strawberries need consistent moisture, especially when they're fruiting, but they definitely don't like soggy feet. Aim for about 1 inch of water per week, increasing it slightly during particularly dry spells in July and August. 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.

Water at the base of the plants rather than overhead, if possible. Our dry summer months help reduce fungal diseases, but it's still best to avoid wetting the foliage unnecessarily. Drip irrigation is ideal for this. Overwatering can lead to root rot, indicated by yellowing leaves and stunted growth. Underwatering will result in dry, brittle leaves and smaller, less juicy berries.

Mulching heavily around your strawberry plants is a great idea. It helps retain moisture in the soil, suppresses weeds, and keeps the berries clean. Straw or wood chips work well in our climate.

Strawberry pruning is pretty straightforward. Throughout the growing season, you'll want to remove any runners (the long stems that sprout new plantlets) if you want the mother plant to put all its energy into fruit production. If you're aiming to expand your strawberry patch, let those runners root!

For June-bearing varieties, renovate the bed after harvest. This means mowing or cutting back the foliage to about an inch above the crown. This encourages new growth and a better harvest next year. Before the first frost around mid- October, remove any dead or diseased foliage to prevent problems over the winter.

Get ready to harvest your first strawberries from early July through mid August. The berries are ripe when they are fully red, fragrant, and have no white or green shoulders. The flavor is best when picked in the morning after the dew has dried.

When harvesting, gently pinch the stem just above the green cap, leaving the cap attached to the berry. This helps them last longer. Pick frequently to encourage continued production. Strawberries won't ripen off the plant, so make sure they are fully colored before picking.

As the first frost approaches in mid- October, harvest any remaining ripe or nearly ripe berries. Even a light frost can damage them. You can use these in jams or smoothies.

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

Gray Mold

• What it looks like: Fuzzy gray mold on berries, especially during wet weather.
• What causes it: A fungal disease that thrives in humid conditions. Wet springs can make this worse.
• How to fix/prevent it: Ensure good air circulation by spacing plants properly and pruning out dead leaves. Remove infected berries 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 berries or berries with peck marks.
• What causes it: Birds love strawberries!
• How to fix/prevent it: Netting is the most effective solution. You can also try shiny deterrents like reflective tape or pinwheels.

Strawberry Crown Borer

• What it looks like: Wilting plants, stunted growth, and small, white grubs inside the crown of the plant.
• What causes it: A beetle larva that tunnels into the crown of the plant, weakening or killing it.
• How to fix/prevent it: Remove and destroy infested plants. Rotate your strawberry bed to a new location.

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: Our mild summer heat means we often don't have the same pest pressure as hotter regions, but late blight can be a concern, especially during wet springs. Choosing resistant varieties and ensuring good air circulation can help. Slugs are always a problem in our damp climate, so be vigilant!

Strawberries benefit from companion planting! Lettuce and spinach make great neighbors as they provide ground cover and help retain moisture. Onions and garlic deter pests, especially slugs. Thyme is also said to repel pests and attract beneficial insects. Borage attracts pollinators and can also deter some pests.

Avoid planting strawberries near broccoli, cauliflower, pepper, and tomato. These plants can harbor verticillium wilt, a soil-borne disease that can affect strawberries. They also compete for the same nutrients in the soil.