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When to Plant Crookneck Squash in Jefferson County, MT

Jefferson County, Montana Zone 5a May

May in the garden — Jefferson County, Montana

Here's what deserves your attention in Jefferson County, Montana this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost June 15
Avg. first frost September 7
Soil temp (4") 32°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
To set up a strong June, finish these tasks
  • Transplants going out: crookneck squash
  • Direct-sowing: crookneck squash

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Yellow crookneck squash is a summer squash with a curved neck and bumpy, bright yellow skin. It has a buttery flavor and is best harvested young when 4-6 inches long.

Jefferson County, Montana is in USDA Zone 5a. The average last spring frost is June 15 and the first fall frost is September 7, giving you a growing season of approximately 84 days.

At an elevation of 7,214 feet, Jefferson County receives approximately 21.5 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Crookneck Squash to ensure they mature before fall.

Jefferson County, MT (Zone 5a) Very short season
84 days
Last Spring Frost June 15
84 growing days
First Fall Frost September 7

Jefferson County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 5 Transplant: Jun 23 🍅 Harvest: Aug 11 – Sep 8
Recommended (50%) ✗ May not fit
Start indoors: May 11 Transplant: Jun 29 🍅 Harvest: Aug 17 – Sep 14
Safe Start (90%) ✗ May not fit
Start indoors: May 19 Transplant: Jul 7 🍅 Harvest: Aug 25 – Sep 22

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 Jefferson County

How your county's soil matches Crookneck Squash's growing requirements.

Soil pH

Your soil pH (6.4–7.9) overlaps with Crookneck Squash's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Jefferson County is excellent for Crookneck Squash — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Crookneck Squash.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Crookneck Squash.

How to Plant Crookneck Squash

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Crookneck Squash

2
successive plantings in your 84-day season

Sow every 5.1 weeks. Last sowing by Jul 09 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 202 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Crookneck Squash

Crookneck Squash needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Crookneck Squash Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Crookneck Squash 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.

Crookneck Squash needs ~604 GDD — county provides 966 GDD Excellent fit

Crookneck Squash Planting Timeline — Jefferson County, MT

Crookneck Squash Planting Calendar

Activity When Date Range
Start Indoors May 11 May 11 – May 25
Transplant Outdoors June 29 Jun 29 – Jul 13
Direct Sow June 22 Jun 22 – Jul 13
Harvest August 17 Aug 17 – Sep 14

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Start Indoors
June Transplant Outdoors Direct Sow
July Transplant Outdoors Direct Sow
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

84 days in Jefferson County

Growing Tips for Crookneck Squash in Jefferson County

Direct sow Crookneck Squash outdoors after June 15 in Jefferson County when soil has warmed and frost danger has passed.

Common pests for Crookneck Squash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

Jefferson County receives only 22" of rain annually. Crookneck Squash needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost on mounds. Pick frequently while small for tender texture. Skin becomes tough and warty on larger fruits. Very productive in warm weather.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Crookneck Squash in Jefferson County, MT?

Jefferson County is in Zone 5a with an average last frost of June 15. Plan your Crookneck Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, MT?

Jefferson County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 15 and first fall frost is September 7.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Jefferson County, MT. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.