When to Plant Grapes in Big Horn County, MT
Big Horn County, Montana gardeners: here's your May plan
Each item below is timed to Big Horn County, Montana's frost dates and soil temperatures. Skip nothing, stress about nothing.
Coming up in June — start thinking about
- Transplants going out: grapes
Grapes are vigorous climbing vines producing clusters of sweet or wine-quality fruits. They require training on a trellis or arbor and annual pruning for best production.
Big Horn County, Montana is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is September 30, giving you a growing season of approximately 140 days.
At an elevation of 5,955 feet, Big Horn County receives approximately 22.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Grapes to ensure they mature before fall.
Big Horn County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.6
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 Big Horn County
How your county's soil matches Grapes's growing requirements.
Soil pH
Your soil pH (6.2–7.6) overlaps with Grapes's range (5.5–7.0), though not a perfect match.
Soil Texture
The loam soil in Big Horn County is excellent for Grapes — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Grapes.
How to Plant Grapes
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Grapes
Grapes needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Grapes Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | — | 2.4" | 0" | ❄️ Dormant |
| May | 3" | 2.9" | 0.1" | 💧 Light watering |
| Jun | 3" | 1.7" | 1.3" | 💧 Light watering |
| Jul | 3" | 2.2" | 0.8" | 💧 Light watering |
| Aug | 3" | 2" | 1" | 💧 Light watering |
| Sep | 3" | 1.8" | 1.2" | 💧 Light watering |
| Oct | — | 2.1" | 0" | ❄️ Dormant |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Big Horn County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Grapes 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.
Grapes Planting Timeline — Big Horn County, MT
Grapes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 3 | Jun 3 – Jun 17 |
· 72" apart · Rows 96" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.7"/week · Only during dry spells
📅 Days to Maturity
730–1095 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
140 days in Big Horn County
Growing Tips for Grapes in Big Horn County
Direct sow Grapes outdoors after May 13 in Big Horn County when soil has warmed and frost danger has passed.
Your 140.0-day growing season in Big Horn County is tight for Grapes (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Provide a strong trellis system. Prune heavily in late winter while dormant. Thin fruit clusters for larger berries. Good air circulation prevents fungal diseases.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Grapes in Other Locations
Frequently Asked Questions
When should I plant Grapes in Big Horn County, MT?
Big Horn County is in Zone 5a with an average last frost of May 13. Plan your Grapes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Big Horn County, MT?
Big Horn County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 13 and first fall frost is September 30.
Your Big Horn County Garden Planner — Free
A 24-page printable planner built for Big Horn County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.