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When to Plant Zucchini in Judith Basin County, MT

Judith Basin County, Montana Zone 4b May

May to-do list for Judith Basin County, Montana

Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 23
Avg. first frost September 19
Soil temp (4") 36°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
June will be here before you know it — start on
  • Transplants going out: zucchini
  • Direct-sowing: zucchini

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Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.

Judith Basin County, Montana is in USDA Zone 4b. The average last spring frost is May 23 and the first fall frost is September 19, giving you a growing season of approximately 119 days.

At an elevation of 6,308 feet, Judith Basin County receives approximately 17.7 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Zucchini to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Zucchini successfully. Mulch heavily to conserve soil moisture.

Judith Basin County, MT (Zone 4b) Short season
119 days
Last Spring Frost May 23
119 growing days
First Fall Frost September 19

Judith Basin County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 4 Transplant: Jun 6 🍅 Harvest: Jul 25 – Sep 19
Recommended (50%) ✗ May not fit
Start indoors: Apr 11 Transplant: Jun 13 🍅 Harvest: Aug 1 – Sep 26
Safe Start (90%) ✗ May not fit
Start indoors: Apr 28 Transplant: Jun 30 🍅 Harvest: Aug 18 – Oct 13

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 Judith Basin County

How your county's soil matches Zucchini's growing requirements.

Soil pH

Your soil pH (6.5–8.2) overlaps with Zucchini's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Judith Basin County is excellent for Zucchini — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Zucchini.

How to Plant Zucchini

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

Succession Planting Zucchini

3
successive plantings in your 119-day season

Sow every 5.1 weeks. Last sowing by Jul 21 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.6″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 731 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Zucchini

Zucchini needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Zucchini Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 5.2" 2.2" 3" 🚿 Regular watering
Jun 5.2" 1.3" 3.9" 🚿 Regular watering
Jul 5.2" 1.7" 3.5" 🚿 Regular watering
Aug 5.2" 1.9" 3.3" 🚿 Regular watering
Sep 5.2" 1.4" 3.8" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Zucchini 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.

Zucchini needs ~525 GDD — county provides 1,190 GDD Excellent fit

Zucchini Planting Timeline — Judith Basin County, MT

Zucchini Planting Calendar

Activity When Date Range
Start Indoors April 11 Apr 11 – Apr 25
Transplant Outdoors June 13 Jun 13 – Jun 27
Direct Sow June 6 Jun 6 – Jun 27
Harvest August 1 Aug 1 – Sep 26

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · 1-2 times/week

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

119 days in Judith Basin County

Growing Tips for Zucchini in Judith Basin County

Direct sow Zucchini outdoors after May 23 in Judith Basin County when soil has warmed and frost danger has passed.

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

Judith Basin County receives only 18" of rain annually. Zucchini needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.

Recommended Zucchini Varieties for Judith Basin County

Quick-producing varieties for shorter seasons

Black Beauty (50d) Raven (48d) Eight Ball (40d)

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zucchini in Judith Basin County, MT?

Judith Basin County is in Zone 4b with an average last frost of May 23. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is Judith Basin County, MT?

Judith Basin County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 23 and first fall frost is September 19.

🌱

Your Judith Basin County Garden Planner — Free

A 24-page printable planner built for Judith Basin 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.

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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 Judith Basin 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.