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The best time to plant cilantro in Seattle is during the cool, damp months of early spring and late summer, specifically from mid-March through May for a spring crop and again from late August through September for a fall harvest.
If you’ve been wondering when to plant cilantro in Seattle, you’re already ahead of the game because this herb thrives in the Pacific Northwest’s mild, overcast climate.
Seattle’s temperatures are perfect for cilantro, which hates the heat and bolts (goes to seed) as soon as the mercury climbs.
Knowing when to plant cilantro in Seattle means syncing your sowing schedule with the city’s rainy seasons, since cilantro loves consistent moisture and cooler soil.
In this post, we’ll cover the exact timing windows, how to avoid bolting, and the best techniques to keep your cilantro lush and leafy for months.
Let’s dig into the details so you can enjoy fresh cilantro from your Seattle garden all year round.
When to Plant Cilantro in Seattle: The Two Main Windows
When to plant cilantro in Seattle really comes down to two distinct windows that avoid the summer heat spike.
The first window is for your spring harvest, and the second is for a fall crop that often tastes even better.
Here’s why these windows are the sweet spots for Seattle gardeners.
1. Spring Planting: Mid-March to Late May
You can start planting cilantro in Seattle as early as mid-March, right after the last hard frost has passed.
The soil is still cool, which is exactly what cilantro seeds need to germinate reliably.
If you plant cilantro in Seattle during this window, you’ll get tender leaves by late April or May.
The key is to sow new seeds every two to three weeks, which gives you a continuous supply rather than one big flush.
By the time June rolls around and temperatures hit the 70s and 80s, your cilantro will start to bolt, so you want to harvest heavily before then.
Planting cilantro in Seattle in May is still okay, but be prepared to move to a shadier spot to extend your harvest.
2. Fall Planting: Late August to Late September
The second best time to plant cilantro in Seattle is in late August, once the intense summer heat has started to fade.
As the days shorten and the nights cool down, cilantro germinates quickly and grows slowly, producing sweeter, more robust leaves.
If you plant cilantro in Seattle in early September, you can harvest through October and even into November with a little protection.
This fall crop often outperforms spring because the cooler temperatures keep the plant from bolting for much longer.
Many Seattle gardeners say the fall harvest is their favorite because the flavor is more intense and the plants are sturdier.
So, when to plant cilantro in Seattle for the longest possible season?
Aim for that late summer window and you’ll be rewarded with months of fresh leaves.
Why Timing Matters So Much for Cilantro in Seattle
Cilantro is a cool-season annual, which means it’s biologically programmed to grow in spring and fall, not in summer.
When you plant cilantro in Seattle during the hot months, the plant thinks it’s time to reproduce, so it immediately sends up flower stalks.
This process, called bolting, makes the leaves turn bitter and small, which ruins your harvest.
Seattle’s summers are getting hotter due to climate change, so timing your plantings outside of July and August is critical.
1. The Bolting Problem During Summer
If you plant cilantro in Seattle in June or July, you’ll likely get a few leaves before the plant shoots up a tall stalk with white flowers.
Once that happens, the leaves lose their punch and the plant puts all its energy into making seeds (coriander).
You can prevent this by always planting cilantro in Seattle when the average high temperature is below 75°F.
That means your best planting cilantro in Seattle times are when the weather is reliably cool and damp, just like spring and fall.
2. Soil Temperature Matters Too
Cilantro seeds germinate best when the soil temperature is between 55°F and 68°F.
When you plant cilantro in Seattle in early spring, the soil is often in that perfect range, especially after a few days of rain.
In late summer, the soil might still be warm from August, so you may need to water deeply and mulch to cool it down before sowing.
Checking the soil temperature with a simple thermometer can help you nail the exact timing for when to plant cilantro in Seattle.
How to Plant Cilantro in Seattle for Success
Once you’ve figured out when to plant cilantro in Seattle, the next step is getting the planting technique right.
Cilantro doesn’t like to be transplanted because its taproot is sensitive, so direct sowing is always your best bet.
Here are a few tried-and-true methods for planting cilantro in Seattle beds or containers.
1. Direct Sow in Rich, Well-Draining Soil
Cilantro prefers loamy soil with plenty of organic matter, like compost or aged manure.
When you plant cilantro in Seattle, sow the seeds about a quarter-inch deep and one inch apart in rows.
Keep the soil consistently moist, but not waterlogged, because soggy soil can cause the seeds to rot.
Seattle’s usual spring rains will do most of the work for you, but you might need to supplement during dry spells.
2. Use Shade Cloth or Partial Shade for Fall Extensions
For a late-summer planting, you can plant cilantro in Seattle in an area that gets morning sun and afternoon shade.
This keeps the soil cooler in September and helps prevent premature bolting.
You can also use a shade cloth to lower the temperature around the plants by 10 degrees, which is a game-changer.
When you plant cilantro in Seattle this way, you essentially create a microclimate that mimics early spring.
3. Succession Planting Every Two Weeks
Instead of planting all your seeds at once, try succession planting to guarantee a steady harvest.
Every two weeks, plant cilantro in Seattle in a new small patch or container.
This way, as one batch starts to bolt, the next batch is ready to take over.
This is the secret to having fresh cilantro in Seattle from March all the way to November.
What About Growing Cilantro Indoors in Seattle?
If you live in an apartment or have a very shaded yard, you can still grow cilantro by using a sunny windowsill.
When you plant cilantro in Seattle indoors, you can do it any time of the year because you control the temperature.
Use a pot that’s at least six inches deep and place it on a south-facing window.
In the darker winter months, you might need a grow light to give the plant 12 to 14 hours of light per day.
Indoor cilantro tends to be less bushy, but you can still enjoy fresh leaves for salads and salsas.
This is a fantastic backup plan if you missed the optimal when to plant cilantro in Seattle window outdoors.
So, When to Plant Cilantro in Seattle? The Final Answer
When to plant cilantro in Seattle is clear: plant in mid-March through May for spring, and again in late August through September for fall.
Planting cilantro in Seattle outside these windows, especially in mid-summer, will lead to quick bolting and bitter leaves.
By sticking to these cool-weather windows, you’ll get tender, aromatic cilantro that tastes far better than anything from the store.
Just remember to keep the soil moist, provide some afternoon shade in early fall, and sow new seeds every couple of weeks.
With this timing, your Seattle garden can produce cilantro almost year-round, giving you a constant supply of this fresh, zesty herb.
Happy planting, and may your cilantro stay lush, green, and bolt-free all season long.