When to Plant Hardy Kiwi in Whatcom County, WA
Hardy kiwi produces grape-sized, smooth-skinned fruits eaten whole without peeling. Unlike fuzzy kiwi, it is extremely cold-hardy to -25F once established.
Whatcom County, Washington is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.
At an elevation of 386 feet, Whatcom County receives approximately 49 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Hardy Kiwi during the growing season.
Whatcom County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
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 Whatcom County
How your county's soil matches Hardy Kiwi's growing requirements.
Soil pH
Your soil pH (5.2–6.4) overlaps with Hardy Kiwi's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Whatcom County is excellent for Hardy Kiwi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Hardy Kiwi will thrive.
How to Plant Hardy Kiwi
Plant Water Budget
Monthly Watering Guide for Hardy Kiwi
Hardy Kiwi needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Hardy Kiwi Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6.1" | 0" | ❄️ Dormant |
| Feb | — | 6.2" | 0" | ❄️ Dormant |
| Mar | — | 4.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| May | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Jun | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Jul | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Aug | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Sep | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Oct | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Nov | — | 7.1" | 0" | ❄️ Dormant |
| Dec | — | 8.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Whatcom County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Hardy Kiwi 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.
Hardy Kiwi Planting Timeline — Whatcom County, WA
Hardy Kiwi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 27 | Apr 27 – May 11 |
· 72" apart · Rows 96" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
1095–1825 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
206 days in Whatcom County
Growing Tips for Hardy Kiwi in Whatcom County
Direct sow Hardy Kiwi outdoors after April 06 in Whatcom County when soil has warmed and frost danger has passed.
Your 206.0-day growing season in Whatcom County is tight for Hardy Kiwi (1095.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Plant male and female vines for pollination. Provide very strong trellising as vines become massive. Prune similarly to grapes. Protect young plants from late spring frost.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Hardy Kiwi in Other Locations
Frequently Asked Questions
When should I plant Hardy Kiwi in Whatcom County, WA?
Whatcom County is in Zone 7b with an average last frost of April 6. Plan your Hardy Kiwi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Whatcom County, WA?
Whatcom County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 29.
Plan Your Garden with Confidence
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