When should I start tomato seeds in Washington State?

Most gardeners in Western Washington start tomato seeds indoors 6–8 weeks before their last frost date — often in March. Eastern Washington gardeners may start slightly earlier depending on their frost date and growing season length.

Can I start seeds in February in Washington?

Yes, but only certain crops. Slow-growing plants like peppers and onions benefit from an early February start indoors. Most vegetables, including tomatoes, do better started in March.

When is it safe to plant seedlings outside in Washington?

It’s generally safe after your last frost date — but soil temperature matters too. Even without frost, cold soil can slow growth. Waiting until the soil warms slightly often results in stronger plants.

Do I need grow lights to start seeds in Washington?

In late winter, natural light in Washington is usually not strong enough for sturdy seedlings. Grow lights help prevent leggy, weak plants, especially for crops started in February or early March.

What vegetables can I direct sow in early spring in Washington?

Cool-season crops like peas, spinach, arugula, radishes, and carrots can often be sown directly into the soil 2–4 weeks before your last frost date.

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February 21, 2026

When to Start Seeds in Washington State

How-to

Spring

Pacific northwest Vegetables Seed starting

When to Start Seeds in Washington State (PNW Planting Timeline Guide) — Seed trays warming under lights while early spring lingers outside — timing begins before the soil does.

Starting seeds feels hopeful.

Tiny trays on a windowsill. Packets spread across the table. A sense that something is about to begin.

But in Washington State, timing matters more than enthusiasm.

In Washington, seed starting isn’t about racing spring — it’s about syncing with it.

Start too early, and you’ll have leggy plants outgrowing their pots before the soil is ready.

Start too late, and you miss the gentle cool-season window our climate does so well.

The good news? Once you understand your frost date and a few simple crop groups, seed starting becomes predictable — not stressful.

Washington State Is Not One Climate

The first thing to understand is this:

Washington isn’t one gardening zone.

Western Washington — from Bellingham to Seattle to Olympia — has:

Cool springs
Long damp winters
Mild summer heat
Generous cloud cover

Eastern Washington has:

Colder winters
Hotter summers
Lower humidity
Larger temperature swings

That means your last frost date is the anchor for everything.

If you’re not sure what yours is, start here:

→ Pacific Northwest Frost Dates

Once you know your last frost date, you can count backward with confidence.

Your Last Frost Date Is the Anchor

Most of Western Washington falls somewhere between late March and early May for the final frost.

Many gardeners around Seattle and Bellingham use:

Mid-April as a rough benchmark.

But check your specific city — even small elevation changes matter.

From there, you count backward based on the crop.

Count backward from your last frost date to time seed starting with Washington’s slow, steady spring.

Seed Starting Timeline for Washington State

Below is a simplified, reliable framework for most Washington gardeners.

10–12 Weeks Before Last Frost

(Late January – February in much of Western WA)

Start indoors:

Peppers
Eggplant
Onions (from seed)
Some slow-growing flowers
These need a long head start because they germinate and grow slowly.

Important: You’ll need strong light. A bright window usually isn’t enough in February here.

6–8 Weeks Before Last Frost

(Late February – March for many Western WA gardens)

Start indoors:

Tomatoes
Broccoli
Cabbage
Cauliflower
Lettuce
Kale
Many herbs

This is the sweet spot for cool-season crops.

Start them too early, and they’ll sit root-bound waiting for soil to warm.

2–4 Weeks Before Last Frost

(March – April in much of Western WA)

Direct sow outside:

Spinach
Arugula
Peas
Carrots
Radishes

Our cool, moist spring soil actually favors these crops.

Just keep an eye on slug pressure — seedlings are vulnerable.

After Last Frost (and Soil Has Warmed)

Direct sow:

Beans
Squash
Cucumbers
Corn
Sunflowers

Even if the frost date has passed, cold soil can stall these.

If nights are still dipping into the 40s, waiting a week often pays off.

The calendar matters — but the soil temperature matters more.

Indoor vs Direct Sowing in Washington

Because our springs are cool and damp, not everything benefits from an indoor start.

In fact, some crops prefer being sown directly in the soil they’ll grow in.

Direct sow works beautifully for:

Root crops
Peas
Greens

Hardy annual flowers

Save indoor seed starting for:

Warm-season crops
Long-season crops
Plants you want an early head start on

Remember: indoor seed starting isn’t mandatory. It’s a tool.

Common Seed Starting Mistakes in the PNW

Starting Too Early

The biggest mistake.

Plants don’t benefit from sitting indoors in oversized pots waiting for May.

Not Enough Light

February in Washington is not bright enough for seedlings without help.

If stems stretch and fall over, it’s usually a light issue.

Overwatering

Our climate is already damp.

Seedlings prefer evenly moist soil — not soggy trays.

A Gentler Way to Think About Timing

You don’t need to start everything at once.

You don’t need 15 varieties.

You don’t need a heated greenhouse.

Start with one tray.

Start with one crop you love.

If it grows, you’ll feel capable.

And that’s more important than perfect timing.

Start with one tray. One crop. One small win

FAQ: When to Start Seeds in Washington State

When should I start tomato seeds in Washington State?: Most gardeners in Western Washington start tomato seeds indoors 6–8 weeks before their last frost date — often in March. Eastern Washington gardeners may start slightly earlier depending on their frost date and growing season length.
Can I start seeds in February in Washington?: Yes, but only certain crops. Slow-growing plants like peppers and onions benefit from an early February start indoors. Most vegetables, including tomatoes, do better started in March.
When is it safe to plant seedlings outside in Washington?: It’s generally safe after your last frost date — but soil temperature matters too. Even without frost, cold soil can slow growth. Waiting until the soil warms slightly often results in stronger plants.
Do I need grow lights to start seeds in Washington?: In late winter, natural light in Washington is usually not strong enough for sturdy seedlings. Grow lights help prevent leggy, weak plants, especially for crops started in February or early March.
What vegetables can I direct sow in early spring in Washington?: Cool-season crops like peas, spinach, arugula, radishes, and carrots can often be sown directly into the soil 2–4 weeks before your last frost date.

Final Thought

Seed starting isn’t about racing the season.

In Washington, it’s about syncing with it.

The soil warms slowly. The light returns gradually. The rhythm is steady.

When you follow that rhythm instead of fighting it, seedlings feel less like a gamble — and more like a conversation with the season.

And that’s when gardening gets easier.