When to Plant Hardy Kiwi in Caribou County, ID
This month in Caribou County, Idaho
We've pulled the most time-sensitive tasks for Caribou County, Idaho this April and put them front and centre. Tackle them in order.
Hardy kiwi produces grape-sized, smooth-skinned fruits eaten whole without peeling. Unlike fuzzy kiwi, it is extremely cold-hardy to -25F once established.
Caribou County, Idaho is in USDA Zone 4b. The average last spring frost is May 30 and the first fall frost is September 16, giving you a growing season of approximately 109 days.
At an elevation of 6,562 feet, Caribou County receives approximately 15.3 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Hardy Kiwi to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Hardy Kiwi successfully. Mulch heavily to conserve soil moisture.
Caribou County Soil Profile
Soil Type
Loam
Soil pH
6.8-8.1
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 Caribou County
How your county's soil matches Hardy Kiwi's growing requirements.
Soil pH
Your soil pH (6.8–8.1) is more alkaline than Hardy Kiwi prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Caribou County is excellent for Hardy Kiwi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Hardy Kiwi.
How to Plant Hardy Kiwi
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.4" | 0" | ❄️ Dormant |
| Apr | — | 1.7" | 0" | ❄️ Dormant |
| May | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Jun | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Jul | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Aug | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Sep | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Oct | — | 1.4" | 0" | ❄️ Dormant |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Caribou 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 — Caribou County, ID
Hardy Kiwi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 27 | Jun 27 – Jul 11 |
· 72" apart · Rows 96" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | Transplant Outdoors |
| 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: too_alkaline
🗺️ USDA Zone
Zone 4b
📆 Growing Season
109 days in Caribou County
Growing Tips for Hardy Kiwi in Caribou County
Direct sow Hardy Kiwi outdoors after May 30 in Caribou County when soil has warmed and frost danger has passed.
Your 109.0-day growing season in Caribou County is tight for Hardy Kiwi (1095.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.
Caribou County receives only 15" of rain annually. Hardy Kiwi needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 Caribou County, ID?
Caribou County is in Zone 4b with an average last frost of May 30. Plan your Hardy Kiwi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Caribou County, ID?
Caribou County, Idaho is in USDA Hardiness Zone 4b. The average last spring frost is May 30 and first fall frost is September 16.
Your Caribou County Garden Planner — Free
A 24-page printable planner built for Caribou County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.