Best Planting Times for Soybeans in Idaho

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

Idaho’s climate is characterized by hot summers and cold winters, with USDA Hardiness Zones ranging from 4a to 7b. These conditions make careful planning essential for successful 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 Idaho, where temperature contrasts can affect soybean development, a greenhouse provides a stable environment for optimal growth. Greenhouses extend the growing season, protect plants from harsh weather, and facilitate year-round cultivation with effective 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 Idaho, 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 Idaho approximately 1-2 weeks after the last spring frost date, ensuring the soil is warm enough for optimal growth.

Average Last Frost Dates for Idaho’s Major Cities

CityAverage Last Frost Date
BoiseApril 15
Idaho FallsMay 1
PocatelloMay 5
Coeur d’AleneMay 10
MeridianApril 22
LewistonApril 18
NampaApril 20
Post FallsMay 8
Mountain HomeApril 25
Twin FallsMay 1

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

Soybean Planting Dates in Idaho

In Idaho, soybean planting typically occurs between April 15 and May 15, depending on the regional climate and soil conditions. This timeframe allows for optimal germination and growth, ensuring that the plants are established before the warmer summer months.

Transplanting and Sowing Soybean Seeds

Sow soybean seeds directly outdoors from May 1 to May 20. The soil temperature should be consistently above 55°F for successful germination. Plant the seeds 1-2 inches deep and space them 4-6 inches apart in rows that are 30 inches apart to allow for proper growth and development.

General Care and Maintenance

Watering

  • Maintain consistently moist soil, particularly during germination and flowering phases. Idaho’s variable precipitation can require supplemental irrigation during dry spells.
  • Water plants at the base to minimize leaf wetness and reduce the risk of diseases.

Fertilizing

  • Incorporate a balanced fertilizer before planting and consider adding additional nutrients during the growing season, especially if soil tests indicate deficiencies.

Pest and Disease Management

  • Regularly check for common pests such as soybean aphids and loopers, as well as diseases like pod and stem blight. Early detection is key in Idaho’s agricultural environment.
  • Utilize integrated pest management strategies to control pests while promoting beneficial insects in the ecosystem.

Harvesting

  • Harvest soybeans when they are firm and have reached the desired size. Timing is important to ensure optimal quality and 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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