Washington’s long, mild growing season allows for a celery planting in early spring, but nailing the exact timing is key. The best time to plant celery in Washington depends on your specific region, from the cool coastal areas to the warmer inland valleys. Celery is a cool-season crop that needs consistent moisture and moderate temperatures, so understanding your local frost dates is essential for a successful harvest.
Understanding Washington’s Climate For Celery
Washington state has diverse climate zones. Western Washington, including Seattle and the Puget Sound region, enjoys mild, wet winters and cool summers. Eastern Washington, around Spokane and the Columbia Basin, has colder winters and hotter, drier summers. Celery thrives in temperatures between 60°F and 70°F, with plenty of water and rich soil.
Because celery has a long growing season of 120 to 140 days, you need to start seeds indoors or time your transplants carefully. The key is to avoid both frost and extreme heat, which can cause bolting or bitter stalks.
Best Time To Plant Celery In Washington
The exact timing for planting celery in Washington breaks down into two main strategies: starting seeds indoors and transplanting outdoors. For most gardeners, the sweet spot is to start seeds indoors about 10 to 12 weeks before the last expected frost date. Then, transplant seedlings outdoors after the soil has warmed and all danger of frost has passed.
Indoor Seed Starting Schedule
Celery seeds are tiny and slow to germinate. They need consistent moisture and warmth to sprout. Here is a simple schedule for Washington gardeners:
- Western Washington (coastal and Puget Sound): Start seeds indoors in mid-February to early March. The last frost date is usually around late March to mid-April. Transplants go out in early to mid-April.
- Eastern Washington (inland and higher elevations): Start seeds indoors in late February to mid-March. The last frost date is typically mid-April to early May. Transplants go out in late April to early May.
- Central Washington (Columbia Basin): Start seeds indoors in early to mid-March. Last frost is around mid-April. Transplants go out in late April.
Use a seed-starting mix and keep the soil temperature around 70°F. Celery seeds need light to germinate, so press them gently into the soil surface without covering them. Mist daily to keep them moist.
Transplanting Outdoors
Wait until nighttime temperatures stay consistently above 50°F before moving your celery plants outside. Harden them off over a week by gradually exposing them to outdoor conditions. Plant them in a spot with full sun to partial shade, with rich, well-draining soil.
Space plants 8 to 10 inches apart in rows 18 to 24 inches apart. Water deeply and regularly, as celery has shallow roots that dry out quickly. Mulch around the plants to retain moisture and keep the soil cool.
Regional Variations Across Washington
Washington is not one-size-fits-all for gardening. Your specific microclimate can shift the best planting window by several weeks. Here are the key regions and their unique considerations.
Western Washington (Puget Sound, Olympic Peninsula)
This region has a maritime climate with mild winters and cool summers. The growing season is long but often cloudy and wet. Celery does well here if you protect it from excessive rain and slugs.
- Best planting window: Transplants outdoors from early April to mid-May.
- Tips: Use raised beds or containers to improve drainage. Cover young plants with row covers if a late frost threatens. Slugs love celery, so use organic slug bait or copper tape.
Eastern Washington (Spokane, Palouse, Columbia Basin)
This region has a continental climate with cold winters and hot, dry summers. The growing season is shorter but sunnier. Celery needs consistent watering and some shade during heat waves.
- Best planting window: Transplants outdoors from late April to early June.
- Tips: Start seeds indoors earlier to compensate for the shorter season. Use drip irrigation to keep soil moist. Provide afternoon shade with shade cloth if temperatures exceed 85°F.
Coastal Areas (Ocean Shores, Long Beach)
Coastal areas have very mild temperatures year-round, with cool summers and minimal frost. The growing season is long, but strong winds and salty air can be challenges.
- Best planting window: Transplants outdoors from late March to early May.
- Tips: Plant in a sheltered spot or use windbreaks. Choose shorter-season celery varieties to avoid bolting in the cool summer.
Step-By-Step Guide To Planting Celery
Follow these steps for a successful celery crop in Washington. Each step is designed to maximize your harvest and minimize problems.
- Choose the right variety. Look for celery varieties that mature in 80 to 100 days, such as ‘Tango’, ‘Golden Self-Blanching’, or ‘Tall Utah’. These work well in Washington’s climate.
- Start seeds indoors. Use seed trays with a sterile seed-starting mix. Sow seeds on the surface and mist them. Cover with a plastic dome to maintain humidity. Keep at 70°F until germination, which takes 14 to 21 days.
- Provide light. Once seedlings emerge, place them under grow lights or in a bright window. Keep lights 2 to 3 inches above the plants for 14 to 16 hours a day.
- Thin seedlings. When seedlings have two true leaves, thin them to one per cell or pot. This prevents overcrowding and promotes strong growth.
- Harden off. One week before transplanting, set seedlings outside for a few hours each day. Gradually increase time and sunlight exposure. Bring them inside if frost is forecast.
- Prepare the garden bed. Celery needs rich, loamy soil with a pH of 6.0 to 7.0. Work in 2 to 3 inches of compost or well-rotted manure before planting. Add a balanced fertilizer like 10-10-10.
- Transplant carefully. Dig holes deep enough to cover the root ball. Space plants 8 to 10 inches apart. Water thoroughly after planting.
- Mulch and water. Apply a 2-inch layer of straw or shredded leaves around the plants. Water deeply once or twice a week, more often in hot weather. Celery needs about 1 to 2 inches of water per week.
- Fertilize monthly. Side-dress with compost or a liquid fertilizer every 4 weeks. Celery is a heavy feeder and benefits from regular nutrition.
- Blanch stalks (optional). For milder, lighter stalks, blanch celery by wrapping the stalks with paper or cardboard two weeks before harvest. This blocks sunlight and reduces bitterness.
Common Problems And Solutions
Even with perfect timing, celery can face challenges in Washington. Here are the most common issues and how to handle them.
Bolting (Premature Flowering)
Bolting happens when celery is stressed by cold temperatures or sudden heat. The plant sends up a flower stalk, and the stalks become tough and bitter. To prevent bolting, avoid transplanting too early and protect plants from frost. Choose bolt-resistant varieties like ‘Tango’ or ‘Conquistador’.
Poor Germination
Celery seeds are tiny and slow to germinate. If your seeds don’t sprout, check the soil temperature. It should be consistently 70°F. Also, ensure the seeds are not buried too deep. Press them into the surface but do not cover them. Use a heat mat to maintain warmth.
Slugs And Snails
Washington’s damp climate is perfect for slugs. They can decimate young celery plants overnight. Use iron phosphate slug bait, set out beer traps, or hand-pick them at dusk. Copper tape around raised beds also works well.
Leaf Spot And Blight
Fungal diseases like leaf spot and early blight can appear in wet conditions. Space plants properly for air circulation, and water at the base to avoid wetting the leaves. Remove infected leaves immediately. Apply a fungicide if needed.
Stunted Growth
If your celery is small and slow-growing, it may need more water or nutrients. Celery is a heavy feeder and requires consistent moisture. Check the soil moisture daily and fertilize every 3 to 4 weeks with a balanced fertilizer.
Harvesting And Storing Celery
Celery is ready to harvest when the stalks are about 8 to 12 inches tall and the base is 2 to 3 inches wide. Harvest individual stalks from the outside of the plant, or cut the entire plant at the base. In Washington, you can often harvest from late summer through early fall.
For best flavor, harvest in the morning when the stalks are crisp. Store celery in the refrigerator in a plastic bag for up to two weeks. You can also blanch and freeze celery for soups and stews.
Frequently Asked Questions
Can I plant celery directly in the ground in Washington?
Direct sowing celery seeds is not recommended in Washington because the growing season is too short and the seeds are slow to germinate. Always start seeds indoors for the best results.
What is the latest time to plant celery in Washington?
The latest safe planting time for celery transplants is early June in most parts of Washington. Planting later may not give the plants enough time to mature before fall frosts, especially in eastern Washington.
Do I need to blanch celery in Washington?
Blanching is optional. It produces milder, lighter stalks, but it also reduces the vitamin content. Many Washington gardeners skip blanching and enjoy the stronger flavor of green celery.
Can I grow celery in containers in Washington?
Yes, celery grows well in containers. Use a pot that is at least 12 inches deep and wide. Fill with rich potting soil and keep it consistently moist. Container-grown celery may need more frequent watering.
How do I protect celery from Washington’s frost?
Use row covers, cloches, or cold frames to protect young plants from late spring frosts. In fall, cover mature plants if a hard frost is forecast. Celery can tolerate light frost but will be damaged by temperatures below 28°F.
Final Tips For Success
Growing celery in Washington is rewarding if you plan ahead. Start seeds indoors early, choose the right variety for your region, and provide consistent care. Monitor your plants for pests and diseases, and water deeply during dry spells. With the right timing and a little patience, you’ll enjoy crisp, homegrown celery from your garden.
Remember that the best time to plant celery in washington is not a single date but a window that depends on your local climate. Use the frost dates for your area as a guide, and always check the weather forecast before transplanting. Happy gardening, and enjoy the fruits of your labor.