When to Plant Onion in Humboldt County, NV
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.
Humboldt County, Nevada is in USDA Zone 5b. The average last spring frost is May 30 and the first fall frost is September 15, giving you a growing season of approximately 108 days.
At an elevation of 5,527 feet, Humboldt County receives approximately 8.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°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.
Humboldt County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.2-8.6
Drainage
Well Drained
Plant Planting Risk Windows
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 Humboldt County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (7.2–8.6) is more alkaline than Onion prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Humboldt 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
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
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 | — | 0.6" | 0" | ❄️ Dormant |
| Feb | — | 0.5" | 0" | ❄️ Dormant |
| Mar | — | 0.4" | 0" | ❄️ Dormant |
| Apr | — | 0.3" | 0" | ❄️ Dormant |
| May | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Jun | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Jul | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Aug | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Sep | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Oct | — | 0.8" | 0" | ❄️ Dormant |
| Nov | — | 0.4" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Humboldt 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 Planting Timeline — Humboldt County, NV
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 25 | Apr 25 – May 9 |
| Transplant Outdoors | May 30 | May 30 – Jun 13 |
| Direct Sow | May 16 | May 16 – Jun 6 |
| Harvest | August 29 | Aug 29 – Oct 17 |
| Fall Sowing | July 7 | Jul 7 – Jul 21 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
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 5b
📆 Growing Season
108 days in Humboldt County
Growing Tips for Onion in Humboldt County
Direct sow Onion outdoors after May 30 in Humboldt County when soil has warmed and frost danger has passed.
Sandy soil in Humboldt 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 108.0-day growing season in Humboldt 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.
Humboldt County receives only 8" 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
Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Humboldt County, NV?
Humboldt County is in Zone 5b with an average last frost of May 30. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Humboldt County, NV?
Humboldt County, Nevada is in USDA Hardiness Zone 5b. The average last spring frost is May 30 and first fall frost is September 15.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Humboldt 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.