When to Plant Onion in Deschutes County, OR
Top priorities for Deschutes County, Oregon gardeners in May
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Deschutes County, Oregon.
To set up a strong June, finish these tasks
- Transplants going out: onion
- Direct-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.
Deschutes County, Oregon is in USDA Zone 6b. The average last spring frost is June 15 and the first fall frost is September 13, giving you a growing season of approximately 90 days.
At an elevation of 221 feet, Deschutes County receives approximately 54.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Onion to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
Deschutes County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.2
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 Deschutes County
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (5.4–6.2) is more acidic than Onion prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Deschutes County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.0%) — 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 | — | 7.6" | 0" | ❄️ Dormant |
| Feb | — | 6.2" | 0" | ❄️ Dormant |
| Mar | — | 4.9" | 0" | ❄️ Dormant |
| Apr | — | 3.8" | 0" | ❄️ Dormant |
| May | — | 3" | 0" | ❄️ Dormant |
| Jun | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Jul | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Aug | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Sep | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Oct | — | 4.9" | 0" | ❄️ Dormant |
| Nov | — | 7.8" | 0" | ❄️ Dormant |
| Dec | — | 9.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Deschutes 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 — Deschutes County, OR
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 11 | May 11 – May 25 |
| Transplant Outdoors | June 15 | Jun 15 – Jun 29 |
| Direct Sow | June 1 | Jun 1 – Jun 22 |
| Harvest | September 14 | Sep 14 – Nov 2 |
| Fall Sowing | July 5 | Jul 5 – Jul 19 |
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 |
| July | Fall Sowing |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
90 days in Deschutes County
Growing Tips for Onion in Deschutes County
Direct sow Onion outdoors after June 15 in Deschutes County when soil has warmed and frost danger has passed.
Your 90.0-day growing season in Deschutes 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.
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 Deschutes County, OR?
Deschutes County is in Zone 6b with an average last frost of June 15. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Deschutes County, OR?
Deschutes County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is June 15 and first fall frost is September 13.
Your Deschutes County Garden Planner — Free
A 24-page printable planner built for Deschutes 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.