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When to Plant Soybeans in McKinley County, NM

Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.

McKinley County, New Mexico is in USDA Zone 5b. The average last spring frost is May 29 and the first fall frost is September 24, giving you a growing season of approximately 118 days.

At an elevation of 7,104 feet, McKinley County receives approximately 10.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 86ยฐF, providing good warmth for Soybeans during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Soybeans will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Soybeans successfully. Mulch heavily to conserve soil moisture.

McKinley County, NM (Zone 5b) Short season
118 days
Last Spring Frost May 29
118 growing days
First Fall Frost September 24

McKinley County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 24 🍅 Harvest: Aug 16 – Oct 11
Recommended (50%) ✗ May not fit
Transplant: May 29 🍅 Harvest: Aug 21 – Oct 16
Safe Start (90%) ✗ May not fit
Transplant: Jun 14 🍅 Harvest: Sep 6 – Nov 1

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in McKinley County

How your county's soil matches Soybeans's growing requirements.

Soil pH

Your soil pH (7.3โ€“8.2) is more alkaline than Soybeans prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in McKinley County warms quickly in spring but drains fast. Soybeans will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Soybeans.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Soybeans.

How to Plant Soybeans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,167 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Soybeans

Soybeans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Soybeans Needs Rainfall You Supplement Action
Jan โ€” 0.8" 0" โ„๏ธ Dormant
Feb โ€” 0.6" 0" โ„๏ธ Dormant
Mar โ€” 0.7" 0" โ„๏ธ Dormant
Apr โ€” 0.4" 0" โ„๏ธ Dormant
May 4.3" 0.3" 4" ๐Ÿšฟ Regular watering
Jun 4.3" 0.4" 3.9" ๐Ÿšฟ Regular watering
Jul 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Aug 4.3" 2" 2.3" ๐Ÿšฟ Regular watering
Sep 4.3" 1.3" 3" ๐Ÿšฟ Regular watering
Oct โ€” 0.9" 0" โ„๏ธ Dormant
Nov โ€” 0.6" 0" โ„๏ธ Dormant
Dec โ€” 0.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in McKinley County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Soybeans Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Soybeans needs ~1,450 GDD — county provides 1,711 GDD Good fit

Soybeans Planting Timeline โ€” McKinley County, NM

Soybeans Planting Calendar

Activity When Date Range
Direct Sow June 5 Jun 5 โ€“ Jun 26
Harvest August 28 Aug 28 โ€“ Oct 23

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

118 days in McKinley County

Growing Tips for Soybeans in McKinley County

Direct sow Soybeans outdoors after May 29 in McKinley County when soil has warmed and frost danger has passed.

Sandy soil in McKinley County dries quickly โ€” mulch Soybeans with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your 118.0-day growing season in McKinley County is tight for Soybeans (80.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Soybeans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

McKinley County receives only 10" of rain annually. Soybeans needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in McKinley County, NM?

McKinley County is in Zone 5b with an average last frost of May 29. Plan your Soybeans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is McKinley County, NM?

McKinley County, New Mexico is in USDA Hardiness Zone 5b. The average last spring frost is May 29 and first fall frost is September 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help McKinley County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for McKinley County, NM. Local conditions may vary. Last updated: April 2026.