When to Plant Kale in Washington (2026 Guide)
Kale is an incredibly nutritious green that thrives in the cool temperatures of Washington. This vegetable is one of the hardiest crops available and can withstand hard frosts, which means you can enjoy a continuous harvest throughout the spring and fall. In Zone 6b, you can expect your last spring frost around April 9, while in Zone 6a, it may be as late as April 20. Understanding your local frost dates is crucial for timing your planting.
Washington's unique climate presents a great opportunity for growing kale. In areas like Arlington or Bellevue, you’ll benefit from a nearly 200-day frost-free growing season. However, in places like Centralia or Olympia, with a shorter season of about 150 days, planning your kale harvest becomes even more essential. By knowing these local conditions, your chance of a successful harvest dramatically increases.
Whether you're a seasoned gardener or a novice, timing is essential for kale cultivation in Washington. Begin sowing seeds indoors as early as late January for those in Zone 5b, while those in Zone 6b can start as soon as mid-February. If you carefully monitor the frost dates and adjust your planting schedule accordingly, you will enjoy delicious, leafier greens that are sweeter after experiencing frost.
Planting Schedule by USDA Zone in Washington
| Zone | Indoor start | Transplant out | Direct sow | Harvest |
|---|---|---|---|---|
| Zone 6b | Start February 15 – March 1, ~6–8 weeks before April 9 | Transplant outdoors from April 10 – April 25, after last frost | Direct sow from April 10 – May 1, after last frost | Harvest from June 1 – October 26, until first fall frost |
| Zone 6a | Start February 25 – March 10, ~6–8 weeks before April 20 | Transplant outdoors from April 21 – May 5, after last frost | Direct sow from April 21 – May 10, after last frost | Harvest from May 25 – October 19, until first fall frost |
| Zone 5b | Start March 1 – March 15, ~6–8 weeks before May 6 | Transplant outdoors from May 7 – May 21, after last frost | Direct sow from May 7 – May 21, after last frost | Harvest from July 1 – October 3, until first fall frost |
Kale Planting Windows in Washington
- Indoor start: For optimal growth, start your kale seeds indoors from February 15 for Zone 6b or beginning February 25 for Zone 6a.
- Transplant outdoors: Transplant your kale outdoors after the last expected frost date, which is around April 10 for Zone 6b or April 21 for Zone 6a.
- Harvest: You can anticipate harvesting kale from June 1 through October 26 in Zone 6b or May 25 through October 19 in Zone 6a.
Common Mistakes Growing Kale in Washington
- Many gardeners in Washington underestimate the impact of late spring frosts. It’s crucial to monitor local forecasts and avoid planting too early, especially in higher elevation areas where frost can linger.
- Several novice gardeners often believe kale can survive the heat, only to face bolting in mid-summer. Understanding the seasonality of your varieties is key, given Washington's temperature fluctuations.
- A frequent mistake is not rotating kale with other crops, particularly other brassicas, to avoid clubroot disease, which can diminish your harvest. Plan your garden layout carefully to maintain healthy soil.
- Some gardeners in humid coastal areas of Washington fail to account for excessive moisture. Too much water can lead to root rot or fungal issues, so proper drainage in your setup is vital.
- Ignoring pest pressures can be another significant issue. Cabbage moths and aphids are common in Washington; using row covers or natural repellents can help protect your kale plants.
Frequently Asked Questions
What if I'm in a cold pocket of Washington?
If you're in a colder area, consider starting kale seeds indoors to get a jump on the season. Use heat mats to encourage germination, and be prepared to protect young plants with row covers during unexpected frosts.
Can I still plant kale in May?
You can plant kale in May, particularly in warmer zones like 6b, but ensure you're planting early in the month, as the heat can affect growth. Keep in mind that late planting may reduce yield.
What are the best companions for kale?
Kale grows best with companions like carrots and garlic that deter pests. Avoid planting with other brassicas to reduce the risk of diseases and optimize yield.
How do I know when to harvest kale?
Kale can be harvested when the leaves are young and tender, typically around 60 days after planting. Cut the outer leaves first, leaving the inner leaves to continue growing for more harvests.
Is it true that kale tastes better after frost?
Yes! Kale's flavor improves after experiencing frost, as it converts starches to sugars, making it sweeter. This can enhance your dishes and make the labor in the garden well worth it.
Keep Learning
City guides in Washington
Other crops in Washington
Typical fall sowing window for Kale in Washington: August 17 – September 7.