Best Planting Times for Soybeans in South Dakota

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingApril 20 – May 20
Transplant OutdoorsJune 10 – June 20
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Soybean Planting Conditions

South Dakota experiences a continental climate, marked by cold winters and warm summers. This variability requires careful planning for soybean cultivation, with attention to the average last frost dates and soil temperatures.

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Useful Tools for Starting Soybeans Indoors

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 South Dakota, utilizing a greenhouse helps mitigate extreme cold temperatures, ensuring consistent warmth for healthy soybean growth. Greenhouses facilitate an extended growing season, protect plants from harsh weather, and allow for year-round cultivation with managed climate conditions.

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 South Dakota, 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 South Dakota approximately 1-2 weeks after the last spring frost date, ensuring the soil is warm enough for optimal growth.

Average Last Frost Dates for South Dakota’s Major Cities

CityAverage Last Frost Date
Sioux FallsMay 10
Rapid CityMay 15
AberdeenMay 8
BrookingsMay 9
MitchellMay 11

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 South Dakota:

Broccoli Planting in South Dakota

Pumpkin Planting in South Dakota

Tomato Planting in South Dakota

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

Starting Soybeans Indoors

In South Dakota (Zone 4b to 5a), begin indoor soybean seed starting between April 15 and May 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 reached at least 55°F consistently. Space the seedlings 6-12 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. South Dakota’s varying weather can necessitate regular monitoring for adequate moisture levels.
  • Water at the base of plants to avoid leaf wetness, reducing the risk of fungal diseases.

Fertilizing

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

Pest and Disease Management

  • Regularly monitor for common pests like soybean aphids, spider mites, and various fungal diseases. Vigilance is essential to protect your soybean crop.
  • Implement organic or integrated pest management methods to shield soybean plants from pests and diseases.

Harvesting

  • Harvest soybeans when they reach the desired firmness and color, typically when the beans are fully mature. Regular harvesting ensures better yield and 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 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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