Blog

When to Plant Amaranth in Union County, NM

Amaranth is an ancient grain crop with edible leaves and seeds, rich in protein and micronutrients. It thrives in warm conditions and is drought-tolerant once established.

Union County, New Mexico is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 9, giving you a growing season of approximately 162 days.

At an elevation of 6,384 feet, Union County receives approximately 17.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 85ยฐF, providing good warmth for Amaranth during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Amaranth will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Amaranth successfully. Mulch heavily to conserve soil moisture.

Union County, NM (Zone 5b) Moderate season
162 days
Last Spring Frost April 30
162 growing days
First Fall Frost October 9

Union County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.9-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (9 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Aug 8 – Sep 26
Recommended (50%) ✓ Fits season (8 days to spare)
Start indoors: Mar 5 Transplant: May 14 🍅 Harvest: Aug 13 – Oct 1
Safe Start (90%) ✓ Fits season (6 days to spare)
Start indoors: Mar 22 Transplant: May 31 🍅 Harvest: Aug 30 – Oct 18

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,464 gal / 100 sq ft
Drought risk

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

Amaranth needs ~1,444 GDD — county provides 2,227 GDD Excellent fit

Amaranth Planting Timeline โ€” Union County, NM

Amaranth Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 โ€“ Mar 19
Transplant Outdoors May 14 May 14 โ€“ May 28
Direct Sow May 7 May 7 โ€“ May 28
Harvest August 13 Aug 13 โ€“ Oct 1

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

162 days

Growing Tips for Union County

Direct sow after last frost when soil is warm. Thin seedlings to 18 inches apart. Harvest leaves when young and tender; harvest seeds when flower heads begin to dry.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Level Up Your Garden

Frequently Asked Questions

When should I plant Amaranth in Union County, NM?

Union County is in Zone 5b with an average last frost of April 30. Plan your Amaranth planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, NM?

Union County, New Mexico is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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