kale

Best Planting Times for Kale in Washington

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingFebruary 15 – March 15
Transplant OutdoorsMarch 15 – April 15
Fall PlantingDirect Sow OutdoorsJuly 15 – August 15

Planting Conditions

Washington has a diverse climate, with the western part of the state experiencing a maritime climate and the eastern part having a more continental climate, falling within USDA Hardiness Zones 6a to 9a. These conditions are favorable for growing cool-season crops like kale, especially in the spring and fall.

Plant kale outdoors approximately 4-6 weeks before the last frost in spring, and 6-8 weeks before the first frost in fall.

Average Last Frost Dates for Washington’s Largest Cities

CityAverage Last Frost Date
SeattleApril 15
SpokaneMay 1
TacomaApril 20
VancouverApril 10
BellevueApril 15
KentApril 15
EverettApril 20
RentonApril 15
Spokane ValleyMay 1
Federal WayApril 15

Average First Frost Dates for Washington’s Largest Cities

CityAverage First Frost Date
SeattleNovember 1
SpokaneOctober 10
TacomaOctober 25
VancouverOctober 20
BellevueNovember 1
KentNovember 1
EverettOctober 25
RentonNovember 1
Spokane ValleyOctober 10
Federal WayNovember 1

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

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Useful Tools for Starting Kale 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 kale the best chance to thrive from the very beginning.
Seeds Image
Browse Kale 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.
Planting Trays Image
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.
Grow Lights Image
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.
Seed Starting Soil Image
Get Seed Starting Soil on Amazon

Garden Tools and Fertilizer

Garden Trowel

A garden trowel is a handy tool that makes transplanting your seedlings easier and more precise, ensuring that each plant is placed at the right depth without damaging the roots.
Garden Trowel Image
Shop Garden Trowels on Amazon

Soil and Fertilizer

Fertilizer is essential for enhancing growth, especially if your soil is nutrient-poor. By enriching the soil, you give your kale plants the nutrients they need to grow robust and produce a bountiful harvest.
Fertilizer Image
Explore Fertilizer on Amazon

Other planting guides for Washington:

Any questions on growing kale? Visit our forum to discuss: Growing Kale

Starting Kale Indoors

In areas like Seattle (Zone 8b), start kale seeds indoors from February 15 to March 15. This timing ensures that seedlings are ready for outdoor transplanting from mid-March to mid-April, after the last frost.

Transplanting Kale Seedlings

Transplant seedlings outdoors from March 15 to April 15, ensuring soil temperatures are consistently above 45°F. Space plants 12-18 inches apart in rows at least 18 inches apart to allow for good air circulation and sunlight exposure.

General Care and Maintenance

Watering:

  • Water deeply and consistently to maintain evenly moist soil. Washington’s varied climate means that regular watering is essential, particularly during drier periods.
  • Water at the base of the plants to keep foliage dry and reduce the risk of diseases.

Fertilizing:

  • Apply a balanced fertilizer at planting and again when the leaves begin to develop. Adding compost before planting helps improve soil fertility and structure.

Pest and Disease Management:

  • Watch out for common pests like aphids, flea beetles, and cabbage worms. Washington’s humid climate in some regions can also encourage fungal diseases, so regular monitoring is important.
  • Use organic or integrated pest management practices to keep your kale plants healthy.

Harvesting Kale:

  • Pick the leaves when they’re large enough to eat but still tender. Regular harvesting promotes new growth and can extend the harvesting season, especially in Washington’s varied climate.
BeeJay
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