When to Plant Pumpkins in Washington

Best Planting Times for Pumpkins in Washington

Planting Method	Activity	Recommended Dates
Indoor Planting	Start Seeds Indoors	April 1 – May 1
Outdoor Planting	Transplant Outdoors	May 15 – June 15
Direct Sowing	Direct Sow Outdoors	May 15 – June 15

Planting Conditions

Hardiness zone map image credit  The United States Department of Agriculture (USDA) 

Washington State’s climate varies significantly between the western and eastern regions. Western Washington, including areas like Seattle, has a maritime climate with mild, wet winters and cool summers. In contrast, Eastern Washington experiences a more arid, continental climate with hotter summers and colder winters. The state falls within USDA Hardiness Zones 4a to 9a, with the western regions typically enjoying a longer growing season.

Start pumpkin seeds indoors from early April to early May to give your plants a head start. Once the danger of frost has passed and soil temperatures have warmed to at least 70°F, transplant the seedlings outdoors. Direct sowing is also recommended from mid-May to mid-June.

Average Last Frost Dates for Washington’s Largest Cities

City	Average Last Frost Date
Seattle	April 1
Spokane	May 10
Tacoma	April 10
Vancouver	April 15
Bellevue	April 1
Kent	April 10
Everett	April 10
Renton	April 10
Spokane Valley	May 10
Yakima	May 1

Average First Frost Dates for Washington’s Largest Cities

City	Average First Frost Date
Seattle	November 15
Spokane	October 10
Tacoma	November 10
Vancouver	November 1
Bellevue	November 15
Kent	November 10
Everett	November 10
Renton	November 10
Spokane Valley	October 10
Yakima	October 15

Please note: These dates are averages and can vary from year to year.

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Useful Tools for Starting Pumpkins Indoors

Using the right tools can save you time and increase your success rate.

Seeds

Quality seeds lead to better germination and healthier plants. Starting with high-quality seeds gives your pumpkins the best chance to thrive from the very beginning.

Browse Pumpkin Seeds on Amazon

Planting Trays

Planting trays help you organize your seedlings and ensure they have enough space to grow before you transplant them outdoors. This makes the process more efficient and increases the chances of strong, healthy plants.

Find Planting Trays on Amazon

Grow Lights

Grow lights are essential if you don’t have enough natural sunlight. They provide your seedlings with the light they need to grow strong and healthy, even in less-than-ideal conditions.

Check out Grow Lights on Amazon

Seed Starting Soil

Using light, fine soil specifically designed for seed starting helps young roots establish quickly and promotes healthy growth. It’s an easy way to give your seedlings the best start possible.

Get Seed Starting Soil on Amazon

Greenhouse Growing

In Washington, where the climate includes mild, wet winters and cool summers, a greenhouse is valuable for protecting your pumpkin plants from excessive moisture during the rainy season and managing temperature fluctuations. It allows you to extend the growing season and ensure a healthier and more productive harvest.

If you grow pumpkins in a greenhouse or polytunnel, though, you should be aware that pumpkins take up a lot of space. You can reduce the amount of space required by training vining pumpkins up a vertical frame or trellis.

Currently, the 8x10x7.5 FT Greenhouse is priced at $999. It’s a great investment for ensuring your pumpkins thrive all year round.


Check the latest price on Amazon.

Fertilizer

Fertilizer is essential to provide your pumpkin plants with the nutrients they need for strong growth and a successful harvest.

Explore Fertilizer on Amazon

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Other planting guides for Washington:

• Kale Planting in Washington
• Broccoli Planting in Washington
• Tomato Planting in Washington

Any questions on growing pumpkins? Visit our forum to discuss: Growing Pumpkins

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Timing the Harvest for Halloween

In Washington, planting pumpkins between mid-May and mid-June will ensure they are ready for Halloween. Pumpkins typically take 90 to 120 days to mature, depending on the variety. Planting by mid-June ensures they’ll be ready by late October.

Harvesting Tips

• Monitor Growth: Regularly check your pumpkins as they grow to ensure they are maturing properly.
• Cut the Pumpkin: Use a sharp knife or pruning shears to cut the pumpkin from the vine, leaving a few inches of stem attached. This helps with storage.
• Cure the Pumpkins: Cure pumpkins in a warm, dry spot for about a week to toughen the skin and improve storage life.

Storage Tips

To extend the shelf life of your harvested pumpkins, follow these storage tips:

• Store pumpkins in a cool, dry place away from direct sunlight.
• Avoid stacking pumpkins to prevent bruising.
• Check regularly for signs of rot or decay.

Common Pests and Diseases

Pest/Disease	Symptoms	Control Methods
Squash Bug	Wilting leaves, yellowing	Handpicking, insecticidal soap
Powdery Mildew	White powdery spots on leaves	Fungicides, improve air circulation
Downy Mildew	Yellow spots on leaves	Fungicides, resistant varieties

Pumpkin Plant Care Tips

Watering:

• Water your pumpkins consistently, especially during dry spells. Ensure the soil remains moist but not waterlogged to avoid root problems.

Fertilizing:

• Apply a balanced fertilizer at planting time and again when the vines start to spread. Adding compost to the soil before planting helps improve soil quality and moisture retention.

Pest and Disease Management:

• Watch out for pests like squash bugs, cucumber beetles, and aphids, which are common in Washington’s climate. Organic methods or integrated pest management can help protect your plants.
• Monitor for powdery mildew and other fungal diseases, especially during humid periods. Ensure good air circulation and avoid overhead watering to reduce disease risks.

Harvesting Pumpkins:

• Harvest pumpkins when they have developed a deep color and the skin is firm. This ensures they are mature and ready for storage.

Smart Tip: Don’t throw away the seeds from the pumpkin after Halloween. Instead, save them and have free pumpkins year after year.