When to Plant Potatoes in Coos County, OR
Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.
Coos County, Oregon is in USDA Zone 9a. The average last spring frost is March 22 and the first fall frost is November 19, giving you a growing season of approximately 242 days.
At an elevation of 96 feet, Coos County receives approximately 38.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Potatoes during the growing season.
Coos County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.8
Drainage
Well Drained
How Much Potatoes to Grow
For a family of 4, plant approximately 20 potatoes plants in about 40 sq ft. In Coos County's 242-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Monthly Watering Guide for Potatoes
Potatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Potatoes Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.5" | 0" | ❄️ Dormant |
| Feb | — | 4.5" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| May | 4.3" | 2.3" | 2" | 💧 Light watering |
| Jun | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Jul | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Aug | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Sep | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Oct | 4.3" | 3.3" | 1" | 💧 Light watering |
| Nov | 4.3" | 5.9" | 0" | ✅ Rainfall sufficient |
| Dec | — | 5.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Coos County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Potatoes Planting Timeline — Coos County, OR
Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 8 | Feb 8 – Feb 22 |
| Transplant Outdoors | March 29 | Mar 29 – Apr 12 |
| Direct Sow | March 22 | Mar 22 – Apr 12 |
| Harvest | June 7 | Jun 7 – Aug 16 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
70–120 days
🧪 Soil pH
Needs 5–6.5 · Your soil: N/A
🗺️ USDA Zone
Zone 9a
📆 Growing Season
242 days in Coos County
Growing Tips for Coos County
Plant seed potatoes (not grocery store potatoes) 4 inches deep in spring. Hill soil around stems as plants grow to prevent greening. Stop watering when plants die back.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Potatoes in Other Locations
Frequently Asked Questions
When should I plant Potatoes in Coos County, OR?
Coos County is in Zone 9a with an average last frost of March 22. Plan your Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Coos County, OR?
Coos County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is March 22 and first fall frost is November 19.
Your Coos County Garden Planner — Free
A 22-page printable planner built for Coos County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.