When to Plant Potatoes in Gilliam County, OR
Top priorities for Gilliam County, Oregon gardeners in May
May is a pivotal month for Gilliam County, Oregon gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Move potatoes into the garden
Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.
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Sow potatoes where they'll grow
Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.
Before June arrives, get these ready
- Starting indoors: potatoes
Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.
Gilliam County, Oregon is in USDA Zone 7b. The average last spring frost is April 25 and the first fall frost is October 15, giving you a growing season of approximately 173 days.
At an elevation of 965 feet, Gilliam County receives approximately 22.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Potatoes during the growing season.
Gilliam County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.7
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 Gilliam County
How your county's soil matches Potatoes's growing requirements.
Soil pH
Your soil pH (5.3–6.7) overlaps with Potatoes's range (5.0–6.5), though not a perfect match.
Soil Texture
The silt loam soil in Gilliam County is excellent for Potatoes — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Potatoes.
Organic Matter
Organic matter is excellent (4.5%) — Potatoes will thrive.
How to Plant Potatoes
Succession Planting Potatoes
Sow every 8 weeks. Last sowing by Jun 17 to harvest before frost.
Plant Water Budget
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 | — | 2.8" | 0" | ❄️ Dormant |
| Feb | — | 2.8" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| May | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Jun | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Jul | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Aug | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Sep | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Oct | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Nov | — | 3.7" | 0" | ❄️ Dormant |
| Dec | — | 3.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Gilliam County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Potatoes 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.
Potatoes Planting Timeline — Gilliam County, OR
Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 7 | Mar 7 – Mar 21 |
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Direct Sow | May 2 | May 2 – May 23 |
| Harvest | July 18 | Jul 18 – Sep 26 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
70–120 days
🧪 Soil pH
Needs 5–6.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
173 days in Gilliam County
Growing Tips for Potatoes in Gilliam County
Direct sow Potatoes outdoors after April 25 in Gilliam County when soil has warmed and frost danger has passed.
Common pests for Potatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
Gilliam County receives only 22" of rain annually. Potatoes needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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 Gilliam County, OR?
Gilliam County is in Zone 7b with an average last frost of April 25. Plan your Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Gilliam County, OR?
Gilliam County, Oregon is in USDA Hardiness Zone 7b. The average last spring frost is April 25 and first fall frost is October 15.
Your Gilliam County Garden Planner — Free
A 24-page printable planner built for Gilliam County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.