Soybean Planting Dates Washington

Best Planting Times for Soybeans in Washington

Planting Method	Activity	Recommended Dates
Outdoor Planting	Indoor Seed Starting	April 15 – May 15
	Transplant Outdoors	June 1 – June 15
Greenhouse Planting	Year-round	Adjust planting based on temperature control in the greenhouse

Planting Conditions

Washington’s climate ranges from the wet coastal regions to the dry eastern areas, providing a unique growing environment for soybeans. The USDA Hardiness Zones span from 5b to 8b, impacting planting and harvesting times.

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Useful Tools for Starting Soybeans Indoors

Utilizing the right tools can streamline the planting process and improve yield.

Seeds

Using quality seeds is crucial for strong germination and healthy plants. High-quality soybean seeds will provide the best chance for your crop to flourish.

Browse Soybean Seeds on Amazon

Planting Trays

Planting trays help organize seedlings and provide adequate space for growth before transferring them outdoors, increasing the likelihood of successful plants.

Find Planting Trays on Amazon

Grow Lights

Grow lights are vital for providing sufficient light to seedlings if natural sunlight is inadequate. They ensure strong growth, especially during early stages.

Check out Grow Lights on Amazon

Seed Starting Soil

Using lightweight soil designed for seed starting promotes quick root establishment and healthy plant growth, ensuring strong seedlings.

Get Seed Starting Soil on Amazon

Greenhouse Growing

In Washington, utilizing a greenhouse can significantly enhance soybean production. It provides a controlled environment that shields plants from harsh weather, enabling an extended growing season and ideal conditions for germination and growth.

Given Washington’s diverse temperatures, consider investing in a 10×12 FT Greenhouse for optimal soybean growth, priced at $1,199.


Check the latest price on Amazon.

Fertilizer

For robust soybean growth in Washington, applying fertilizer is essential for replenishing soil nutrients and supporting vigorous plant development.

Check out Fertilizer on Amazon

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Plant soybeans outdoors in Washington approximately 1-2 weeks after the last spring frost date, ensuring the soil is warm enough for optimal growth.

Average Last Frost Dates for Washington’s Major Cities

City	Average Last Frost Date
Seattle	April 15
Spokane	May 1
Tacoma	April 20
Vancouver	April 25
Bellevue	April 20
Everett	April 15

Disclaimer: Frost dates are average estimates, and actual conditions may vary. It is recommended to monitor local forecasts and adapt planting decisions accordingly.

Other planting guides for Washington:

Broccoli Planting in Washington

Pumpkin Planting in Washington

Tomato Planting in Washington

Any questions on growing soybeans? Visit our forum to discuss: Growing Soybeans.

Starting Soybeans Indoors

In Washington, begin indoor soybean seed starting around April 1 to April 15. This timeline ensures healthy seedlings ready for outdoor transplantation starting from late May to early June once the risk of frost has passed.

Transplanting Soybean Seedlings

Transplant soybean seedlings outdoors from June 1 to June 15, ensuring the soil temperature has warmed above 55°F consistently. Space the seedlings 4-6 inches apart in rows that are at least 30 inches apart for optimal growth.

General Care and Maintenance

Watering

• Provide consistent and deep watering to maintain evenly moist soil. Washington’s varying climate requires regular monitoring of soil moisture levels.
• Water at the base of plants to avoid leaf wetness, which helps reduce the risk of fungal diseases.

Fertilizing

• Apply a balanced fertilizer during planting and when the first pods start forming. Incorporating compost before planting can improve soil fertility and structure.

Pest and Disease Management

• Regularly monitor for common pests such as soybean aphids and spider mites. Vigilance is essential to ensure healthy crops.
• Implement organic or integrated pest management practices to protect soybean plants from pests and diseases.

Harvesting

• Harvest soybeans once the pods are firm and the seeds inside are fully developed. Regularly checking the pods will help determine the best time to harvest for optimal quality.

The importance of good soil

Before starting to grow it is important to take a step back and find the condition of the soil in your garden, The optimal soil is a blend that includes the mineral-rich dirt along with organic rich organic matter that plants need to thrive.

In my garden I try to compost as much as possible, so I can mix in the nutrient rich compost in my soil. I use both hot composting of food scraps and cold composting of all organic garden “waste”..
If you don’t have the time or space for composting, it is possible to get compost ready to use in garden centers and Community Composting.
You can read more on Community Composting here: https://www.epa.gov/sustainable-management-food/community-composting

If you are uncertain of the quality of your soil, you can get easy to use soil tests at amazon for 17 dollars. Check latest prices here: Soil testing kit.

Also remember to check out how much sunlight your growing area gets, and that the rain drains well. If you treat your soil well and plan your crops according to your climate you will succeed with any plant you want.

The satisfaction when you harvest your own produce is well worth the time you put in 🙂