Seattle's Unique Growing Climate
Seattle's maritime climate is unlike anywhere else in the US. Mild winters, cool summers, abundant rain, and persistent cloud cover create both opportunities and challenges for container gardeners.
Seattle Challenges:
- Limited sunlight: Overcast skies 200+ days. Heat-lovers struggle.
- Cool summers: Average July high only 76°F. Tomatoes ripen slowly.
- Rain drainage: Waterlogged containers kill roots quickly
- Fungal diseases: High humidity promotes mildew and blight
- Slugs: The PNW's #1 garden pest loves the moisture
Seattle Advantages:
- Long growing season: 250+ days frost-free. Year-round greens possible.
- Mild winters: Kale, chard, spinach grow through winter
- Perfect for greens: Cool temps = no bolting, sweet flavor
- Natural irrigation: Rain does much of the watering for you
- Incredible nurseries: Swansons, Sky Nursery, Ravenna Gardens
Best Plants for Seattle
Thrives in Seattle (Cool-Season Champions)
Year-round harvest possible. Best lettuce climate in the US.
Grow through winter. Frost sweetens flavor.
Spring and fall crops. Sugar snap, snow peas.
Fall harvest best. Cool temps = tight heads.
Carrots, beets, radishes. Deep containers.
Thrive in Seattle's moisture and mild temps.
Challenging but Possible (Heat-Lovers)
Choose early varieties: Stupice (52 days), Early Girl. Place in sunniest spot. May need to ripen indoors.
Small-fruited varieties (shishito, padron) better than bells. Need warmest microclimate.
Struggles in cool weather. Grow indoors or in warmest spot. African Blue Basil more tolerant.
Possible in sunny spots. Choose early varieties. Watch for mildew.
Managing Seattle's Rain
- Drainage is critical: Use pots with multiple drainage holes. Elevate on pot feet.
- Fast-draining mix: Add extra perlite (30%) to potting soil for better drainage
- Covered areas: Place containers under eaves or balcony overhangs when possible
- Rain covers: Use clear plastic sheets over tomatoes to prevent blight
- Self-watering pots: Actually helpful in Seattle - they drain excess while storing some
Seattle Planting Calendar
February-March (Early Spring)
Plant peas, lettuce, spinach, radishes outdoors. Start tomatoes/peppers indoors under lights.
May-June (Late Spring)
Transplant tomatoes, peppers after soil warms (late May). Direct sow beans, cucumbers.
July-August (Summer)
Plant fall crops: broccoli, kale, carrots. Succession plant lettuce.
September-November (Fall)
Plant garlic. Harvest summer crops. Greens continue growing.
December-January (Winter)
Harvest overwintering kale, chard. Plan for spring. Order seeds.
Where to Buy in Seattle
Nurseries
- • Swansons Nursery (Ballard)
- • Sky Nursery (Shoreline)
- • Ravenna Gardens
- • Molbak's (Woodinville)
Resources
- • Seattle Tilth Alliance
- • P-Patch Community Gardens
- • WSU Master Gardeners
- • Territorial Seed Company
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