Best Planting Times for Soybeans in Arizona

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

Arizona’s climate is primarily characterized by hot summers and mild winters, providing a unique environment for soybean cultivation. The USDA Hardiness Zones in Arizona range from 8a to 10b.

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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 Arizona, where temperatures can soar, a greenhouse provides a stable environment that protects soybeans from extreme heat and sunlight. Greenhouses allow for better control over humidity and temperature, extending the growing season and reducing water evaporation. This creates optimal conditions for soybean growth.

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

Average Last Frost Dates for Arizona’s Major Cities

CityAverage Last Frost Date
PhoenixApril 15
TucsonApril 20
FlagstaffJune 1
YumaApril 10
PrescottMay 10
KingmanApril 15
Show LowJune 15
Sierra VistaApril 25
Lake Havasu CityApril 10
Casa GrandeApril 20

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

Starting Soybeans Indoors

In Arizona, it is recommended to begin indoor soybean seed starting from April 1 to April 15. This timeframe allows for strong seedlings that can be transplanted outdoors by mid-April, taking advantage of the warm growing season.

Transplanting Soybean Seedlings

Transplant soybean seedlings outdoors from April 15 to May 1, ensuring that the soil temperature is consistently above 55°F for optimal germination and growth. Space the seedlings 2-4 inches apart in rows spaced 30-36 inches apart for proper air circulation and growth.

General Care and Maintenance

Watering

  • Maintain consistent watering, aiming for approximately 1-1.5 inches of water per week, especially during dry spells. Arizona’s arid climate can lead to quick soil moisture loss, so monitor closely.
  • Water at the base of the plants to prevent water stress and encourage deep root growth.

Fertilizing

  • Incorporate a balanced fertilizer at planting, particularly one high in phosphorus to promote strong root development. A soil test can guide specific nutrient needs.

Pest and Disease Management

  • Keep an eye out for common pests such as aphids, bean beetles, and spider mites. Regular inspections can help catch and control infestations early.
  • Consider using integrated pest management practices, including crop rotation and introducing beneficial insects, to keep soybean plants healthy and productive.

Harvesting

  • Harvest soybeans when the pods are firm and dry, usually in late summer to early fall. Regular harvesting prevents pods from becoming too mature and enhances 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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