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When to Plant Onion in Cibola County, NM

Cibola County, New Mexico Zone 6a May

Cibola County, New Mexico gardeners: here's your May plan

A quick May briefing for Cibola County, New Mexico gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 23
Avg. first frost October 2
Soil temp (4") 53°F
Watering Critical
Pest pressure Low
Daylight 13.8 hrs
  1. Plant out onion

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Seed onion outdoors

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Looking ahead to June
  • Starting indoors: onion

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Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

Cibola County, New Mexico is in USDA Zone 6a. The average last spring frost is May 23 and the first fall frost is October 2, giving you a growing season of approximately 132 days.

At an elevation of 4,342 feet, Cibola County receives approximately 15.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 88°F, providing good warmth for Onion during the growing season. Sandy soil warms quickly in spring — great for early planting — but Onion will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Onion successfully. Mulch heavily to conserve soil moisture.

Cibola County, NM (Zone 6a) Short season
132 days
Last Spring Frost May 23
132 growing days
First Fall Frost October 2
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Cibola County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.1-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Aug 12 – Sep 30
Recommended (50%) ✗ May not fit
Start indoors: Apr 18 Transplant: May 23 🍅 Harvest: Aug 22 – Oct 10
Safe Start (90%) ✗ May not fit
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Sep 9 – Oct 28

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 Cibola County

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

Soil pH

Your soil pH (7.1–8.6) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Onion.

How to Plant Onion

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 728 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Onion

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

Month Onion Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 0.8" 0" ❄️ Dormant
Apr 0.6" 0" ❄️ Dormant
May 4.3" 0.4" 3.9" 🚿 Regular watering
Jun 4.3" 0.5" 3.8" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 4.3" 1.4" 2.9" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Cibola County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Onion 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" — every day above 50°F 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.

Onion needs ~1,680 GDD — county provides 2,112 GDD Good fit

Onion Planting Timeline — Cibola County, NM

Onion Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 – May 2
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 9 May 9 – May 30
Harvest August 22 Aug 22 – Oct 10
Fall Sowing July 24 Jul 24 – Aug 7

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors
July Fall Sowing
August Fall Sowing Harvest
September Harvest
October Harvest
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

132 days in Cibola County

Growing Tips for Onion in Cibola County

Direct sow Onion outdoors after May 23 in Cibola County when soil has warmed and frost danger has passed.

Sandy soil in Cibola County dries quickly — mulch Onion with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your 132.0-day growing season in Cibola County is tight for Onion (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

Cibola County receives only 15" of rain annually. Onion needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Cibola County, NM?

Cibola County is in Zone 6a with an average last frost of May 23. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cibola County, NM?

Cibola County, New Mexico is in USDA Hardiness Zone 6a. The average last spring frost is May 23 and first fall frost is October 2.

🌱

Your Cibola County Garden Planner — Free

A 24-page printable planner built for Cibola County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Cibola County, NM. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.