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When to Plant Onion in Douglas County, NV

Douglas County, Nevada Zone 6b May

Your May planting checklist for Douglas County, Nevada

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Douglas County, Nevada.

Avg. last frost May 12
Avg. first frost October 10
Soil temp (4") 45°F
Watering Critical
Pest pressure Low
Daylight 14.1 hrs
  1. Harden off and plant onion

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

June will be here before you know it — start on
  • 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.

Douglas County, Nevada is in USDA Zone 6b. The average last spring frost is May 12 and the first fall frost is October 10, giving you a growing season of approximately 151 days.

At an elevation of 5,945 feet, Douglas County receives approximately 9.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98°F, so Onion may need afternoon shade and extra watering during peak heat. 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.

Douglas County, NV (Zone 6b) Moderate season
151 days
Last Spring Frost May 12
151 growing days
First Fall Frost October 10
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Douglas County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jul 31 – Sep 18
Recommended (50%) ✓ Fits season (11 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Aug 11 – Sep 29
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: May 2 Transplant: Jun 6 🍅 Harvest: Sep 5 – Oct 24

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 Douglas County

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

Soil pH

Your soil pH (7.3–8.7) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Onion.

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
0.3″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 1,670 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 0.7" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 0.5" 0" ❄️ Dormant
Apr 0.3" 0" ❄️ Dormant
May 4.3" 0.2" 4.1" 🚿 Regular watering
Jun 4.3" 0.4" 3.9" 🚿 Regular watering
Jul 4.3" 1.4" 2.9" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 1.3" 3" 🚿 Regular watering
Oct 4.3" 0.9" 3.4" 🚿 Regular watering
Nov 0.5" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Douglas 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 ~2,468 GDD — county provides 3,548 GDD Excellent fit

Onion Planting Timeline — Douglas County, NV

Onion Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 – Apr 21
Transplant Outdoors May 12 May 12 – May 26
Direct Sow April 28 Apr 28 – May 19
Harvest August 11 Aug 11 – Sep 29
Fall Sowing August 1 Aug 1 – Aug 15

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
August Fall Sowing Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

151 days in Douglas County

Growing Tips for Onion in Douglas County

Direct sow Onion outdoors after May 12 in Douglas County when soil has warmed and frost danger has passed.

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

With summer highs reaching 98°F in Douglas County, provide afternoon shade for Onion and water deeply in the morning.

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

Douglas County receives only 10" 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 Douglas County, NV?

Douglas County is in Zone 6b with an average last frost of May 12. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Douglas County, NV?

Douglas County, Nevada is in USDA Hardiness Zone 6b. The average last spring frost is May 12 and first fall frost is October 10.

🌱

Your Douglas County Garden Planner — Free

A 24-page printable planner built for Douglas County (Zone 6b). 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 Douglas County, NV. 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.