Knowing when to plant in Washington State is the single most important factor for a successful garden. Our unique climate, split by the Cascade Mountains, means timing is everything to avoid frosts and maximize growth.
This guide breaks down the best planting times for vegetables, flowers, and more across Washington’s distinct regions. You’ll get clear schedules and tips to make your garden thrive.
When to Plant in Washington State – Best Planting Times For
Washington isn’t just one garden; it’s at least two. The wet, mild west side and the dry, extreme east side have completely different rules. Your planting dates depend entirely on which side of the mountains you call home.
Understanding Washington’s Planting Zones
First, find your USDA Hardiness Zone. This tells you your average annual extreme minimum winter temperature. It’s crucial for choosing perennial plants that will survive your winters.
Western Washington (Puget Sound, Coast): Mostly zones 8a to 9a. Winters are mild, but springs are cool and wet.
Eastern Washington (Spokane, Tri-Cities, Yakima): Zones 6a to 7b. Winters are colder, summers are hotter and drier.
The microclimates are real! Urban Seattle is warmer than rural foothills. Waterfront areas are milder. Always observe your own garden’s conditions.
The Last Frost Date: Your Garden’s Starting Gun
For annual vegetables and flowers, the last spring frost date is your key date. Planting too early can wipe out tender seedlings overnight.
- Western WA: Last frost typically falls between mid-March and late April. Coastal areas are earlier; inland valleys are later.
- Eastern WA: Last frost is later, usually from late April to mid-May. Higher elevations can be even later.
Always check local historical data for your specific town. A local nursery will have the best advice for your area.
Vegetable Planting Guide by Season
Think of your garden in three seasons: cool, warm, and fall. Some plants love chill, others need heat.
Cool-Season Crops (Plant in Early Spring & Fall)
These can be planted as soon as the soil is workable in spring—often 4-6 weeks before your last frost. Many can also be planted in late summer for a fall or winter harvest.
- Direct Sow Early Spring: Peas, spinach, kale, arugula, radishes, carrots, beets, turnips, lettuce, Swiss chard.
- Transplant Early Spring: Broccoli, cabbage, cauliflower, Brussels sprouts (started indoors earlier).
- Pro Tip: Succession plant lettuce and radishes every 2 weeks for a continuous harvest.
Warm-Season Crops (Plant After Last Frost)
These are frost-sensitive. Wait until both the soil and air have warmed up consistently. Rushing these leads to stunted growth.
- Transplant After Danger of Frost: Tomatoes, peppers, eggplants, cucumbers, squash, pumpkins, melons.
- Direct Sow After Frost: Beans, corn, cucumbers, squash.
- Pro Tip: Use black plastic mulch or cloches in Western WA to warm the soil faster for heat-lovers like tomatoes.
Fall & Winter Harvest Crops
In Western WA especially, you can grow food year-round. The key is timing your planting so crops mature before the deepest winter chill or can overwunder.
- Plant in Mid-to-Late Summer: Kale, carrots, beets, scallions, overwintering broccoli, and garlic (planted in October for next July).
- Use row covers to extend the season into winter for greens.
Flower Planting Calander
Flowers follow similar rules. Hardy annuals can go out early, while tender annuals must wait for warmth.
Spring-Blooming Bulbs & Perennials
Plant bulbs like tulips and daffodils in the fall, October-November. Divide most perennials in early spring or early fall.
Annual Flowers
- Hardy Annuals (Plant early spring): Pansies, violas, snapdragons, calendula.
- Half-Hardy/Tender Annuals (Plant after last frost): Zinnias, marigolds, petunias, cosmos, impatiens.
Regional Planting Calendars: A Quick-Start Guide
Here are generalized timelines. Adjust based on your exact location and that year’s weather.
Western Washington (Puget Sound Area Example)
- February-March: Plant peas, spinach, leafy greens. Start tomatoes & peppers indoors.
- April-May: After last frost, plant potatoes, carrots, beets. Transplant broccoli/cabbage. By late May, transplant tomatoes/peppers (with protection).
- June: Direct sow beans, corn, squash. Plant tender annual flowers.
- July-August: Sow fall carrots, beets, kale for winter harvest.
- September-October: Plant garlic and overwintering onions.
Eastern Washington (Spokane/Yakima Area Example)
- April: As soil thaws, plant peas, radishes, spinach, kale. Start warm-season crops indoors.
- Mid-May to Early June: After last frost, transplant all warm-season crops. Direct sow beans, corn, cucumbers.
- June-July: Focus on consistent watering during hot, dry spells.
- Late July: Sow quick-maturing greens for fall.
- October: Plant garlic before the ground freezes.
Essential Tips for Success in Washington Gardens
A few extra pieces of advice can make a huge difference in our specific climate.
Soil Preparation is Key: Our western soils are often acidic clay; eastern soils can be sandy and alkaline. Amend with compost every year. A soil test is a great investment.
Master Watering: West side: be careful not to overwater in spring. East side: deep, infrequent watering and mulching are essential for summer.
Use Season Extension Tools: Cold frames, row covers, and cloches are invaluable for getting a head start in spring and extending harvest in fall, especially in cooler western areas.
Keep a Garden Journal: Note your planting dates, what worked, and what didn’t. This is your most valuble tool for refining your timing each year.
Common Mistakes to Avoid
- Planting tomatoes outside in Western WA on Mother’s Day regardless of the weather (wait for true warmth).
- Ignoring crop rotation, especially for the cabbage family, to prevent disease buildup.
- Forgetting to harden off seedlings started indoors before transplanting them outside.
- Not adjusting for microclimates—your neighbor’s sunny slope may warm up weeks before your shady backyard.
FAQ: Your Washington Planting Questions Answered
When is the best time to plant tomatoes in Washington?
In Western WA, wait until late May or early June, unless using protective cloches. In Eastern WA, transplant after your last frost, typically from mid-May onward.
What can I plant in early spring in Washington?
Cool-season crops are your go-to: peas, lettuce, radishes, spinach, kale, and onion sets can all go in as soon as the soil is workable.
How do I find my exact last frost date?
Search online for “last frost date [Your City, WA]” or consult your local county Master Gardener program. They have the most localized data.
Can I grow vegetables year-round in Washington?
In Western Washington, yes, with the use of cold-hardy crops and season extension. In Eastern WA, the season is shorter and more defined by harsh winters.
When should I plant perennials and shrubs?
The ideal times are early fall (so roots establish before winter) or early spring (after frost but before summer heat). Avoid planting in the peak of summer.
Gardening in Washington State is a rewarding challenge that hinges on perfect timing. By aligning your planting with the natural rhythms of your specific region, you set the stage for a bountiful and beautiful garden. Start with the cool-season crops, patiently wait for true warmth for the tender ones, and don’t forget to plan for a productive fall. Your garden will thank you with a longer, more succesful harvest season.