Best Planting Times for Soybeans in Oregon

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingApril 15 – May 15
Transplant OutdoorsMay 20 – June 5
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Soybean Planting Conditions

Oregon’s climate is primarily Mediterranean, characterized by wet winters and dry summers. Soybeans thrive best in regions with well-drained soils and ample sunlight, and the growing season in Oregon allows for optimal soybean cultivation.

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Useful Tools for Starting Soybeans 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 soybeans the best chance to thrive from the very beginning.
Soybean Seeds
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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
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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
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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
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Greenhouse Growing

In Oregon, where temperature fluctuations can pose challenges to soybean growth, a greenhouse provides a stable environment for optimal development. Greenhouses extend the growing season, protect plants from extreme weather, and allow for year-round cultivation with proper climate control.

Consider investing in a 10×12 FT Greenhouse priced at $1,199 to ensure your soybeans thrive in a controlled environment.
Greenhouse Image 1
Greenhouse Image 2
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Fertilizer

For optimal soybean growth in Oregon, supplementing with fertilizer can ensure abundant and healthy harvests. Quality fertilizer helps replenish nutrients in the soil and promotes vigorous plant growth.
Fertilizer Image
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Plant soybeans outdoors in Oregon approximately 1-2 weeks after the last spring frost date, ensuring the soil is warm enough for optimal growth.

Average Last Frost Dates for Oregon’s Major Cities

CityAverage Last Frost Date
PortlandApril 15
SalemApril 20
EugeneApril 30
BendMay 15
CorvallisApril 25

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 Oregon:

Broccoli Planting in Oregon

Pumpkin Planting in Oregon

Tomato Planting in Oregon

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

Starting Soybeans Indoors

In cities like Portland (Zone 8b), begin indoor soybean seed starting between April 15 and May 15. This timeline ensures that seedlings are healthy and ready for outdoor transplantation starting from late May to early June, ensuring they grow well before summer heat sets in.

Transplanting Soybean Seedlings

Transplant soybean seedlings outdoors from June 1 to June 15, ensuring the soil temperature has consistently warmed above 60°F. Space the seedlings 4-6 inches apart in rows with at least 30 inches between rows for optimal growth.

General Care and Maintenance

Watering

  • Provide consistent and deep watering to maintain evenly moist soil. Oregon’s mild climate allows for regular watering, but it’s crucial to prevent soil dryness during crucial growing periods.
  • Water at the base of the plants to avoid leaf wetness, which can help reduce the risk of fungal diseases.

Fertilizing

  • Apply a balanced fertilizer during planting and as the plants start flowering. Incorporating compost before planting can enhance soil fertility and overall structure.

Pest and Disease Management

  • Regularly monitor for common pests like aphids and soybean loops. Pest vigilance is crucial in Oregon to protect your plants from potential infestations.
  • Implement organic or integrated pest management methods to protect soybean plants from pests and diseases effectively.

Harvesting

  • Harvest soybeans when the pods are plump and seeds are firm. Regular harvesting promotes continuous growth and improves overall yield.

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 organicrich organic matter that plants need to thrive.


In my garden I try to compost as mutch as possible, so I can mix in the nutrient ritch compost in my soil. I use both hot composting of food scraps and cold composting of all organic garden “waste”..
If you dont 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 you 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 🙂

BeeJay
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