when to plant sweet peas in seattle

When is the Best Time to Plant Sweet Peas in Seattle?

For Seattle gardeners eager to cultivate vibrant, fragrant sweet peas, timing is everything. The optimal planting window typically falls between March and May for direct sowing, or starting indoors 6-8 weeks before the last expected frost and transplanting later. This allows the plants to establish themselves and bloom prolifically during the region’s mild summer months.

Understanding Seattle’s Climate for Sweet Peas

Seattle’s climate, characterized by mild, wet winters and cool, relatively dry summers, presents a unique situation for growing sweet peas. Unlike regions with harsh winters, Seattle rarely experiences prolonged freezing temperatures, making early spring planting possible. However, the long, cool spring can also extend the growing season, allowing for a later planting if necessary.

Spring Planting (March – May): The Sweet Spot

The most common and generally successful approach is to plant sweet peas in early spring. Here’s a breakdown:

• Timing: Aim for planting seeds directly in the ground in March or April, once the soil has warmed slightly and is workable. Starting seeds indoors in February or March and transplanting seedlings after the last frost is also a great option.
• Soil Preparation: Ensure the soil is well-drained and amended with compost or other organic matter. Sweet peas thrive in rich soil.
• Sunlight: Choose a location that receives at least six hours of sunlight daily.
• Support: Provide a trellis, fence, or other support structure for the vines to climb.

Starting Seeds Indoors vs. Direct Sowing

Seattle gardeners have the option of starting sweet pea seeds indoors or directly sowing them into the garden. Each method has its advantages:

• Starting Indoors: This provides a head start, especially in cooler springs. It allows you to protect the seedlings from pests and diseases.
• Direct Sowing: This is simpler and eliminates the need for transplanting. However, it may result in a slightly later bloom time.

Whichever method you choose, consider nicking or soaking the seeds before planting to improve germination rates. See more information about Sweet Pea (Lathyrus odoratus) at Wikipedia.

Extending the Bloom Time

To prolong the sweet pea blooming season in Seattle, consider these tips:

• Succession Planting: Plant seeds every two to three weeks from March to May to ensure a continuous supply of blooms.
• Deadheading: Regularly remove spent flowers to encourage new growth and more blooms.
• Watering and Fertilizing: Provide consistent moisture and fertilize with a balanced fertilizer every few weeks.

Frequently Asked Questions (FAQs)

What happens if I plant sweet peas too late in Seattle?

Planting too late may result in shorter bloom times as the plants will be exposed to hotter summer temperatures. The flowers may also be less vibrant.

Can I plant sweet peas in the fall in Seattle?

While some gardeners have success with fall planting, it’s generally not recommended in Seattle due to the risk of waterlogged soil and fungal diseases over the winter. Spring planting is more reliable.

How deep should I plant sweet pea seeds?

Plant sweet pea seeds about 1 inch deep.

Do sweet peas need full sun in Seattle?

Yes, sweet peas need at least six hours of sunlight daily to thrive and produce abundant blooms.

What kind of soil do sweet peas need?

Sweet peas prefer well-drained, fertile soil that is rich in organic matter. Amend the soil with compost or well-rotted manure before planting.

Summary

Planting sweet peas in Seattle requires careful timing to maximize their blooming potential. Aim for a spring planting window between March and May, either directly sowing seeds or starting them indoors. Ensure well-drained soil, plenty of sunlight, and proper support. By following these guidelines, you can enjoy a beautiful and fragrant display of sweet peas throughout the summer months.