When to Plant Sunchoke in Whitman County, WA
Sunchokes (Jerusalem artichokes) are a native sunflower relative grown for their knobby, nutty-flavored tubers. They are extremely productive and nearly impossible to eradicate.
Whitman County, Washington is in USDA Zone 6a. The average last spring frost is May 10 and the first fall frost is September 29, giving you a growing season of approximately 142 days.
At an elevation of 1,541 feet, Whitman County receives approximately 14.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Sunchoke during the growing season. With low rainfall, drip irrigation is essential for growing Sunchoke successfully. Mulch heavily to conserve soil moisture.
Whitman County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.7
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.
Plant Water Budget
Sunchoke Planting Timeline — Whitman County, WA
Sunchoke Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 24 | May 24 – Jun 7 |
| Harvest | September 13 | Sep 13 – Nov 8 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
110–150 days
Soil pH
6 – 7.5
USDA Zone
Zone 6a
Growing Season
142 days
Growing Tips for Whitman County
Plant tubers 4 inches deep in early spring. Contain plants with barriers as they spread aggressively. Harvest after frost or leave in ground and dig as needed through winter.
Companion Planting
Good Companions
Level Up Your Garden
Sunchoke in Other Locations
Frequently Asked Questions
When should I plant Sunchoke in Whitman County, WA?
Whitman County is in Zone 6a with an average last frost of May 10. Plan your Sunchoke planting based on this frost date — see the calendar above for exact timing.
What planting zone is Whitman County, WA?
Whitman County, Washington is in USDA Hardiness Zone 6a. The average last spring frost is May 10 and first fall frost is September 29.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Whitman County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.
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