When to Plant Squash (Summer) in Carbon County, MT
Your May gardening checklist
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Carbon County, Montana.
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Transplant squash (summer) outside
Your last frost (May 13) has passed. These warm-season crops can handle outdoor soil now.
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Outdoor sowing time: squash (summer)
Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.
Looking ahead to June
- Starting indoors: squash (summer)
Summer squash includes zucchini, yellow crookneck, and pattypan varieties that are harvested young and tender. They are prolific producers in warm weather.
Carbon County, Montana is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is September 28, giving you a growing season of approximately 138 days.
At an elevation of 5,849 feet, Carbon County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Squash (Summer) to ensure they mature before fall.
Carbon 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 Carbon County
How your county's soil matches Squash (Summer)'s growing requirements.
Soil pH
Your soil pH (6.8–8.1) overlaps with Squash (Summer)'s range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Carbon County is excellent for Squash (Summer) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.3%). Annual compost additions will help Squash (Summer).
How to Plant Squash (Summer)
Succession Planting Squash (Summer)
Sow every 5.1 weeks. Last sowing by Jul 25 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Squash (Summer)
Squash (Summer) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Squash (Summer) Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 2.6" | 0" | ❄️ Dormant |
| May | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Jun | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Jul | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Aug | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Sep | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Oct | — | 2.2" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Carbon County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Squash (Summer) 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.
Squash (Summer) Planting Timeline — Carbon County, MT
Squash (Summer) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 8 | Apr 8 – Apr 22 |
| Transplant Outdoors | May 27 | May 27 – Jun 10 |
| Direct Sow | May 20 | May 20 – Jun 10 |
| Harvest | July 15 | Jul 15 – Sep 16 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
45–65 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
138 days in Carbon County
Growing Tips for Squash (Summer) in Carbon County
Direct sow Squash (Summer) outdoors after May 13 in Carbon County when soil has warmed and frost danger has passed.
Common pests for Squash (Summer) in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.
Carbon County receives only 23" of rain annually. Squash (Summer) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct sow after last frost on mounds. Harvest frequently when fruits are 6-8 inches for best texture. Check plants daily as they grow rapidly in summer heat.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Squash (Summer) in Other Locations
Frequently Asked Questions
When should I plant Squash (Summer) in Carbon County, MT?
Carbon County is in Zone 5a with an average last frost of May 13. Plan your Squash (Summer) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Carbon County, MT?
Carbon County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 13 and first fall frost is September 28.
Your Carbon County Garden Planner — Free
A 24-page printable planner built for Carbon 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.