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When to Plant Onion in Lincoln County, NM

Lincoln County, New Mexico Zone 7a May

What to do in May

Welcome to May in Zone 7a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 7
Avg. first frost October 9
Soil temp (4") 48°F
Watering Critical
Pest pressure Low
Daylight 13.8 hrs
  1. Time to transplant onion

    Your last frost (May 7) has passed. These warm-season crops can handle outdoor soil now.

Get ahead of 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.

Lincoln County, New Mexico is in USDA Zone 7a. The average last spring frost is May 7 and the first fall frost is October 9, giving you a growing season of approximately 155 days.

At an elevation of 5,466 feet, Lincoln County receives approximately 16.3 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.

Lincoln County, NM (Zone 7a) Moderate season
155 days
Last Spring Frost May 7
155 growing days
First Fall Frost October 9

Lincoln County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Aug 1 – Sep 19
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Aug 6 – Sep 24
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Aug 18 – Oct 6

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 Lincoln County

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

Soil pH

Your soil pH (7.0–8.7) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Lincoln 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 (0.9%). 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
0.4″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 924 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" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.6" 3.7" 🚿 Regular watering
Jul 4.3" 2.5" 1.8" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 2.2" 2.1" 💧 Light watering
Oct 4.3" 1.5" 2.8" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Lincoln 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 2,480 GDD Excellent fit

Onion Planting Timeline — Lincoln County, NM

Onion Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 23 Apr 23 – May 14
Harvest August 6 Aug 6 – Sep 24
Fall Sowing July 31 Jul 31 – Aug 14

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

Month-by-Month Timeline

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

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 7a

📆 Growing Season

155 days in Lincoln County

Growing Tips for Onion in Lincoln County

Direct sow Onion outdoors after May 07 in Lincoln County when soil has warmed and frost danger has passed.

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

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

Lincoln County receives only 16" 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 Lincoln County, NM?

Lincoln County is in Zone 7a with an average last frost of May 7. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lincoln County, NM?

Lincoln County, New Mexico is in USDA Hardiness Zone 7a. The average last spring frost is May 7 and first fall frost is October 9.

🌱

Your Lincoln County Garden Planner — Free

A 24-page printable planner built for Lincoln County (Zone 7a). 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 Lincoln 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.