When to Plant Onion in Lake County, OR
Your May game plan for Lake County, Oregon
We've pulled the most time-sensitive tasks for Lake County, Oregon this May and put them front and centre. Tackle them in order.
A few tasks this May that'll pay off in June
- Transplants going out: onion
- Direct-sowing: onion
- Fall sowing: onion
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.
Lake County, Oregon is in USDA Zone 6b. The average last spring frost is June 16 and the first fall frost is September 7, giving you a growing season of approximately 83 days.
At an elevation of 1,236 feet, Lake County receives approximately 12.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Onion during the growing season. With low rainfall, drip irrigation is essential for growing Onion successfully. Mulch heavily to conserve soil moisture.
Lake County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.4
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 Lake County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (5.7–6.4) overlaps with Onion's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Lake County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Onion will thrive.
How to Plant Onion
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
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 | — | 2" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.3" | 0" | ❄️ Dormant |
| Apr | — | 0.8" | 0" | ❄️ Dormant |
| May | — | 0.7" | 0" | ❄️ Dormant |
| Jun | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Jul | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Aug | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Sep | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Oct | — | 1.2" | 0" | ❄️ Dormant |
| Nov | — | 1.9" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Lake 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 — Lake County, OR
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 12 | May 12 – May 26 |
| Transplant Outdoors | June 16 | Jun 16 – Jun 30 |
| Direct Sow | June 2 | Jun 2 – Jun 23 |
| Harvest | September 15 | Sep 15 – Nov 3 |
| Fall Sowing | June 29 | Jun 29 – Jul 13 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow Fall Sowing |
| July | Fall Sowing |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| 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: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
83 days in Lake County
Growing Tips for Onion in Lake County
Direct sow Onion outdoors after June 16 in Lake County when soil has warmed and frost danger has passed.
Your 83.0-day growing season in Lake 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.
Lake County receives only 13" 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
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Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Lake County, OR?
Lake County is in Zone 6b with an average last frost of June 16. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lake County, OR?
Lake County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is June 16 and first fall frost is September 7.
Your Lake County Garden Planner — Free
A 24-page printable planner built for Lake 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.