When to Plant Kiwi in San Juan County, WA
May in San Juan County, Washington — your action list
Your San Juan County, Washington garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
Kiwi vines produce fuzzy, tangy-sweet fruits and need both male and female plants for pollination. Hardy kiwi varieties (A. arguta) are suited to colder climates.
San Juan County, Washington is in USDA Zone 9a. The average last spring frost is March 26 and the first fall frost is November 3, giving you a growing season of approximately 222 days.
At an elevation of 371 feet, San Juan County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Kiwi to ensure they mature before fall.
San Juan County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.4
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 San Juan County
How your county's soil matches Kiwi's growing requirements.
Soil pH
Your soil pH (5.4–6.4) overlaps with Kiwi's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in San Juan County is excellent for Kiwi — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Kiwi.
Organic Matter
Organic matter is excellent (4.8%) — Kiwi will thrive.
How to Plant Kiwi
Plant Water Budget
Monthly Watering Guide for Kiwi
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 | Kiwi Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.7" | 0" | ❄️ Dormant |
| Feb | — | 4.7" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Apr | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| May | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Jun | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Jul | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Aug | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Sep | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Oct | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Nov | 4.3" | 6.4" | 0" | ✅ Rainfall sufficient |
| Dec | — | 6.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in San Juan County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
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.
Kiwi Planting Timeline — San Juan County, WA
Kiwi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 9 | Apr 9 – Apr 23 |
· 72" apart · Rows 96" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
1095–1825 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
222 days in San Juan County
Growing Tips for Kiwi in San Juan County
Direct sow Kiwi outdoors after March 26 in San Juan County when soil has warmed and frost danger has passed.
Your 222.0-day growing season in San Juan County is tight for Kiwi (1095.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Plant one male vine for every 6-8 female vines. Provide a very sturdy arbor or T-bar trellis. Prune heavily in winter. Protect young plants from frost in cold zones.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Kiwi in Other Locations
Frequently Asked Questions
When should I plant Kiwi in San Juan County, WA?
San Juan County is in Zone 9a with an average last frost of March 26. Plan your Kiwi planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Juan County, WA?
San Juan County, Washington is in USDA Hardiness Zone 9a. The average last spring frost is March 26 and first fall frost is November 3.
Your San Juan County Garden Planner — Free
A 24-page printable planner built for San Juan 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.