Washington’s cool, rainy springs provide ideal conditions for bok choy to mature without bolting. Knowing the best time to plant bok choy in washington can make the difference between a crisp harvest and a disappointing crop of bitter, flowering plants. This guide walks you through exactly when and how to plant bok choy in Washington’s unique climate zones, from the Puget Sound lowlands to the higher elevations east of the Cascades.
Bok choy thrives in cool weather, so timing is everything. In Washington, you have two main planting windows: early spring and late summer. Let’s break down each season so you can plan your garden with confidence.
Best Time To Plant Bok Choy In Washington
The ideal window for spring planting is from mid-March to early April in western Washington. For eastern Washington, wait until late April or early May. The soil temperature should be at least 40°F, but bok choy germinates best between 55°F and 65°F. If you plant too early, cold soil can stunt growth. Too late, and the heat triggers bolting.
For a fall harvest, plant bok choy in late July through mid-August. This timing lets the crop mature during the cooler days of September and October. Fall-planted bok choy often tastes sweeter because light frosts increase sugar content.
Spring Planting Window
In western Washington, the last frost date typically falls between March 15 and April 15. Start seeds indoors 4 to 6 weeks before your last frost date, or direct sow seeds outdoors once the soil is workable. Use a soil thermometer to check—bok choy seeds won’t germinate well below 40°F.
- Direct sow seeds 1/4 to 1/2 inch deep
- Space seeds 6 inches apart in rows 12 inches apart
- Thin seedlings to 8–10 inches apart once they have two true leaves
- Water consistently to keep soil moist but not waterlogged
For eastern Washington, where winters are colder and springs come later, wait until soil temperatures reach at least 45°F. This usually happens in late April or early May. Use row covers or cold frames to protect young plants from late frosts.
Fall Planting Window
Fall planting is often more forgiving than spring. The key is to count backward from your first expected frost date. In western Washington, that’s usually mid-October to early November. Count back 45 to 60 days—the time bok choy needs to mature—and plant in late July or early August.
- Choose a spot with partial shade if summer heat lingers
- Soak seeds overnight to speed germination in warm soil
- Plant seeds 1/2 inch deep and water deeply
- Mulch around seedlings to keep soil cool and retain moisture
- Thin to 8–10 inches apart once seedlings are established
For eastern Washington, first frost often arrives in late September or early October. Plant bok choy seeds in early to mid-August. Use shade cloth if temperatures exceed 85°F during establishment.
Understanding Washington’s Climate Zones
Washington has diverse microclimates that affect planting times. Western Washington, including Seattle, Tacoma, and Olympia, has mild winters and cool summers. Eastern Washington, including Spokane and Yakima, experiences hotter summers and colder winters. Coastal areas like the Olympic Peninsula have even milder conditions.
Western Washington
In the Puget Sound region, spring arrives gradually. Soil warms slowly, so direct sowing too early can lead to rot. Start seeds indoors in late February or early March, then transplant outdoors in mid-March to early April. For fall crops, plant in early August.
- Ideal spring planting: March 15 to April 15
- Ideal fall planting: August 1 to August 15
- Use raised beds for better drainage in rainy springs
- Consider using cold frames to extend the season
Eastern Washington
Eastern Washington has a continental climate with hot summers and cold winters. Spring planting should wait until late April or early May. Fall planting happens in early to mid-August. The shorter growing season means you need to be precise with timing.
- Ideal spring planting: April 20 to May 10
- Ideal fall planting: August 1 to August 10
- Use shade cloth for summer plantings
- Water deeply to combat dry conditions
Coastal And Mountain Areas
Coastal areas like Port Angeles and Aberdeen have very mild temperatures year-round. You can plant bok choy almost any month except deep winter. Mountain areas like the Cascades have short growing seasons—plant in late May for spring and early July for fall.
Factors That Affect Planting Time
Several variables influence when you should plant bok choy. Soil temperature, day length, and variety all play a role. Pay attention to these factors to avoid bolting or poor growth.
Soil Temperature
Bok choy seeds germinate best when soil is between 55°F and 65°F. Use a soil thermometer to check. If the soil is too cold, seeds may rot. If it’s too warm, germination rates drop. In Washington, spring soil often stays cool until late March or early April.
Day Length
Bok choy is sensitive to day length. Long days (over 14 hours) can trigger bolting, especially in warm weather. Spring planting in Washington takes advantage of shorter days. Fall planting also works because days are getting shorter. Avoid planting in late spring when days are long and temperatures rise.
Variety Selection
Some bok choy varieties are more bolt-resistant than others. Look for varieties like ‘Joi Choi,’ ‘Win-Win,’ or ‘Shanghai Green.’ These handle Washington’s temperature swings better. Baby bok choy varieties mature faster, which is helpful for fall planting.
Step-By-Step Planting Guide
Follow these steps for a successful bok choy crop in Washington. Adjust timing based on your specific location and microclimate.
Preparing The Soil
Bok choy prefers rich, well-draining soil with a pH between 6.0 and 7.5. Amend your garden bed with compost or well-rotted manure a few weeks before planting. Work the soil to a depth of 8–10 inches. Remove rocks and debris.
- Test soil pH with a home kit
- Add lime if pH is below 6.0
- Mix in 2–3 inches of compost
- Rake the bed smooth
- Water the bed a day before planting
Sowing Seeds
Direct sowing is easiest for bok choy. Plant seeds 1/4 to 1/2 inch deep. Space seeds 6 inches apart in rows 12 inches apart. Cover lightly with soil and water gently. Keep the soil moist until seeds germinate, which takes 4–7 days.
- Plant 2–3 seeds per spot, then thin to the strongest seedling
- Water with a fine spray to avoid washing away seeds
- Use row covers to protect from pests and frost
- Thin seedlings when they have 2–3 true leaves
Transplanting Seedlings
If you started seeds indoors, harden them off before transplanting. Set seedlings outside for a few hours each day, increasing time over a week. Transplant on a cloudy day or in the evening to reduce transplant shock.
- Dig holes slightly larger than the root ball
- Space plants 8–10 inches apart
- Water thoroughly after transplanting
- Apply a layer of mulch around plants
- Water regularly for the first week
Caring For Bok Choy In Washington
Bok choy is relatively low-maintenance, but a few care tips ensure a good harvest. Focus on consistent watering, pest control, and timely harvesting.
Watering
Bok choy needs consistent moisture to grow tender leaves. Water deeply once or twice a week, depending on rainfall. In western Washington, you may need less watering. In eastern Washington, water more frequently. Avoid overhead watering to prevent leaf diseases.
- Water at the base of plants
- Use drip irrigation or soaker hoses
- Mulch to retain moisture and suppress weeds
- Check soil moisture 2 inches below the surface
Fertilizing
Bok choy is a heavy feeder. Apply a balanced fertilizer (10-10-10) at planting time. Side-dress with compost or a nitrogen-rich fertilizer when plants are 4–6 inches tall. Avoid over-fertilizing, which can cause lush growth that attracts pests.
Pest And Disease Management
Common pests in Washington include flea beetles, aphids, and cabbage worms. Use row covers to exclude pests. Handpick caterpillars. Spray aphids with a strong stream of water. Rotate crops to prevent soil-borne diseases.
- Use floating row covers from planting to harvest
- Plant companion plants like dill or marigolds
- Apply neem oil for severe infestations
- Remove diseased plants immediately
Harvesting Bok Choy
Bok choy is ready to harvest 45–60 days after planting. Harvest when the plant is 6–12 inches tall, depending on the variety. Cut the entire plant at the base, or harvest outer leaves as needed. For baby bok choy, harvest at 4–6 inches tall.
In Washington, spring-planted bok choy is ready by late May or June. Fall-planted bok choy is ready by September or October. Light frosts improve flavor, but hard freezes can damage plants. Cover plants if a hard freeze is forecast.
Common Mistakes And How To Avoid Them
Even experienced gardeners make mistakes with bok choy. Here are the most common issues in Washington and how to fix them.
Planting Too Late In Spring
If you plant bok choy in May or June, warm temperatures and long days cause bolting. Stick to the early spring window. If you miss it, wait for the fall planting window.
Overcrowding
Bok choy needs space to develop full heads. Thin seedlings to 8–10 inches apart. Overcrowding leads to small, spindly plants and increased disease risk.
Inconsistent Watering
Bok choy is sensitive to drought stress. Inconsistent watering causes tough leaves and bolting. Water deeply and regularly, especially during dry spells in eastern Washington.
Extending The Growing Season
With a few techniques, you can grow bok choy nearly year-round in Washington. Use cold frames, row covers, or greenhouses to protect plants from cold and heat.
Using Cold Frames
Cold frames allow you to plant earlier in spring and later in fall. Place a cold frame over your garden bed 2–3 weeks before planting. This warms the soil and protects seedlings from frost.
Succession Planting
Plant a new batch of bok choy every 2–3 weeks during the spring window. This ensures a continuous harvest. For fall, plant all at once because the window is shorter.
Frequently Asked Questions
Can I plant bok choy in Washington in summer?
Summer planting is risky because heat causes bolting. If you want a summer crop, choose bolt-resistant varieties and provide shade. Plant in a spot with afternoon shade.
What is the best bok choy variety for Washington?
‘Joi Choi’ and ‘Win-Win’ are excellent for Washington’s climate. They are bolt-resistant and grow well in cool weather. Baby bok choy varieties like ‘Mei Qing Choi’ mature quickly.
How do I know if my bok choy is bolting?
Bolting is when the plant sends up a flower stalk. Leaves become bitter and tough. Harvest immediately if you see a central stalk forming. Bolting is triggered by heat and long days.
Can I grow bok choy in containers in Washington?
Yes, bok choy grows well in containers. Use a pot at least 8 inches deep with drainage holes. Place the container in a spot with 4–6 hours of sun. Water more frequently because containers dry out faster.
Should I soak bok choy seeds before planting?
Soaking seeds overnight can speed germination, especially in warm soil. It’s not necessary but can help. If you soak, plant seeds immediately after draining.
Final Tips For Success
Planting bok choy at the right time is the most important step. Monitor soil temperature and weather forecasts. In Washington, spring and fall are your best friends. Keep soil moist, watch for pests, and harvest promptly.
With these guidelines, you can enjoy fresh, homegrown bok choy from your Washington garden. Experiment with different varieties and planting dates to find what works best in your microclimate. Happy gardening.