Best Planting Times for Soybeans in Colorado

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingApril 15 – May 15
Transplant OutdoorsJune 1 – June 15
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Soybean Planting Conditions

Colorado’s diverse climate offers a range of environments, from arid plains to mountainous regions. The state’s USDA Hardiness Zones range from 3b to 7a, influencing the optimal conditions for 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 Colorado, where temperature fluctuations can challenge 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 Colorado, 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 Colorado approximately 1-2 weeks after the last spring frost date, ensuring the soil is warm enough for optimal growth.

Average Last Frost Dates for Colorado’s Major Cities

CityAverage Last Frost Date
DenverMay 7
Colorado SpringsMay 15
AuroraMay 14
Fort CollinsMay 19
LakewoodMay 11
ThorntonMay 18
ArvadaMay 10
WestminsterMay 12
PuebloMay 23
CentennialMay 16

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 Colorado:

Kale Planting in Colorado

Broccoli Planting in Colorado

Pumpkin Planting in Colorado

Tomato Planting in Colorado

Any questions on growing soybeans? Visit our forum to discuss: Gardening Forum.

Starting Soybean Seeds Indoors

In cities like Denver (Zone 5b), begin soybean seed starting indoors between April 15 and May 15. This timeline ensures healthy seedlings are ready for outdoor transplantation starting from late May to early June, after the last frost date has passed.

Transplanting Soybean Seedlings

Transplant soybean seedlings outdoors from June 1 to June 10, ensuring the soil temperature is consistently above 55°F. Space the seedlings 2-3 inches apart in rows at least 30 inches apart for optimal growth.

General Care and Maintenance

Watering

  • Provide consistent and deep watering to maintain evenly moist soil. Colorado’s dry climate necessitates regular watering to prevent soil dryness.
  • Water at the base of plants to avoid leaf wetness, reducing the risk of fungal diseases.

Fertilizing

  • Apply a balanced fertilizer at planting and again mid-season as necessary. Incorporating compost before planting can enhance soil fertility and provide essential nutrients.

Pest and Disease Management

  • Regularly monitor for common pests such as soybean aphids and rootworms. Proactive management is key in maintaining healthy crops.
  • Utilize integrated pest management techniques to minimize pest issues while protecting soybean health.

Harvesting

  • Harvest soybeans when the pods are firm, and the beans feel full. Regular harvesting informs better yields 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 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 into 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 🙂

BeeJay
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