When to Plant Yam in Pacific County, WA
June in the garden — Pacific County, Washington
A quick June briefing for Pacific County, Washington gardeners — what's urgent, what's next, and what can wait.
True yams are tropical tubers distinct from sweet potatoes, producing large starchy roots that can weigh several pounds. They are a staple food in tropical regions worldwide.
Pacific County, Washington is in USDA Zone 9a. The average last spring frost is April 18 and the first fall frost is October 29, giving you a growing season of approximately 194 days.
At an elevation of 14 feet, Pacific County receives approximately 47.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Yam during the growing season.
Pacific County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.2
Drainage
Well Drained
Yam 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 Pacific County
How your county's soil matches Yam's growing requirements.
Soil pH
Your soil pH (5.6–6.2) is within Yam's preferred range (5.5–6.5).
Soil Texture
The silt loam soil in Pacific County is excellent for Yam — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.5%) — Yam will thrive.
How to Plant Yam
Yam Water Budget
Monthly Watering Guide for Yam
Yam needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Yam Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 7.2" | 0" | ❄️ Dormant |
| Feb | — | 5" | 0" | ❄️ Dormant |
| Mar | — | 4.5" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| May | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Jun | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Jul | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Aug | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Sep | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Oct | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Nov | — | 8" | 0" | ❄️ Dormant |
| Dec | — | 6.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Pacific County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Yam 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.
Yam Planting Timeline — Pacific County, WA
Yam Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 7 | Mar 7 – Mar 21 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Direct Sow | April 18 | Apr 18 – May 9 |
| Harvest | October 24 | Oct 24 – Feb 20 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Harvest |
| February | Harvest |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Harvest |
| November | Harvest |
| December | Harvest |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
180–330 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: ideal
🗺️ USDA Zone
Zone 9a
📆 Growing Season
194 days in Pacific County
Growing Tips for Yam in Pacific County
Direct sow Yam outdoors after April 18 in Pacific County when soil has warmed and frost danger has passed.
Your 194.0-day growing season in Pacific County is tight for Yam (180.0-330.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Plant tuber pieces in mounds of loose, rich soil. Provide sturdy trellising for climbing vines. Yams require a long, warm growing season of 8-11 months. Harvest when vines die back.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Yam in Other Locations
Frequently Asked Questions
When should I plant Yam in Pacific County, WA?
Pacific County is in Zone 9a with an average last frost of April 18. Plan your Yam planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pacific County, WA?
Pacific County, Washington is in USDA Hardiness Zone 9a. The average last spring frost is April 18 and first fall frost is October 29.
Your Pacific County Garden Planner — Free
A 22-page printable planner built for Pacific 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.