Blog

When to Plant Zucchini in Park County, MT

Park County, Montana Zone 5a May

Top priorities for Park County, Montana gardeners in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Park County, Montana.

Avg. last frost May 24
Avg. first frost September 20
Soil temp (4") 33°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
  1. Seed zucchini outdoors

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

To set up a strong June, finish these tasks
  • Transplants going out: zucchini
  • Starting indoors: zucchini

Instant PDF download. No spam, unsubscribe any time.

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.

Park County, Montana is in USDA Zone 5a. The average last spring frost is May 24 and the first fall frost is September 20, giving you a growing season of approximately 119 days.

At an elevation of 6,994 feet, Park County receives approximately 22.2 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.

Park County, MT (Zone 5a) Short season
119 days
Last Spring Frost May 24
119 growing days
First Fall Frost September 20
Share this guide:

Park County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Apr 9 Transplant: May 28 🍅 Harvest: Jul 16 – Sep 10
Recommended (50%) ✓ Fits season (0 days to spare)
Start indoors: Apr 19 Transplant: Jun 7 🍅 Harvest: Jul 26 – Sep 20
Safe Start (90%) ✗ May not fit
Start indoors: May 13 Transplant: Jul 1 🍅 Harvest: Aug 19 – Oct 14

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 Park County

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

Soil pH

Your soil pH (6.5–7.6) overlaps with Zucchini's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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 22 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 529 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.6" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 5.2" 2.5" 2.7" 🚿 Regular watering
Jun 5.2" 1.7" 3.5" 🚿 Regular watering
Jul 5.2" 1.8" 3.4" 🚿 Regular watering
Aug 5.2" 2.3" 2.9" 🚿 Regular watering
Sep 5.2" 2" 3.2" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Park 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 — Park County, MT

Zucchini Planting Calendar

Activity When Date Range
Start Indoors April 19 Apr 19 – May 3
Transplant Outdoors June 7 Jun 7 – Jun 21
Direct Sow May 31 May 31 – Jun 21
Harvest July 26 Jul 26 – Sep 20

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

Month-by-Month Timeline

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

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 5a

📆 Growing Season

119 days in Park County

Growing Tips for Zucchini in Park County

Direct sow Zucchini outdoors after May 24 in Park 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.

Park County receives only 22" 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 Park 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 Park County, MT?

Park County is in Zone 5a with an average last frost of May 24. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is Park County, MT?

Park County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 24 and first fall frost is September 20.

🌱

Your Park County Garden Planner — Free

A 24-page printable planner built for Park 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Park 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.