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When to Plant Zucchini in USDA Zone 4b

Zone 4b Zone 4b May

Zone 4b gardeners: here's your May plan

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Zone 4b.

Avg. last frost May 11
Avg. first frost October 2
  1. Sow zucchini where they'll grow

    Your soil is warming°F — warm enough for these to germinate without babying.

June prep starts now
  • Transplants going out: zucchini
  • Starting indoors: zucchini
Send me my free Zone 4b Planting Guide →
Zucchini

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.

In Zone 4b, the average last spring frost is around May 1 and the first fall frost is around October 3, giving you a growing season of approximately 155 days.

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Zone 4b Moderate season
155 days
Last Spring Frost May 1
155 growing days
First Fall Frost October 3

Zucchini Planting Timeline — Zone 4b

Where Is USDA Zone 4b?

The map below highlights the states that contain Zone 4b. Click any state to see the Zucchini planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Zucchini Planting Calendar — Zone 4b

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest July 10 Jul 10 – Sep 4

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

Month-by-Month Timeline

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

Free Zone 4b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4b with start dates, transplant windows, and harvest times.

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Growing Conditions

Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · Moderate — regular watering

Days to Maturity

45–60 days

Soil pH

6 – 7.5

Zone Temperature Range

°F to °F average annual minimum

Growing Season

155 days (Zone average)

Planting Specifications

Planting Depth1 inches
Plant Spacing30 inches apart
Row Spacing42 inches between rows

Succession Planting Zucchini in Zone

4
successive plantings in Zone 's ~155-day season

Sow every 5.1 weeks for continuous harvest throughout the season.

Growing Tips for Zucchini in Zone

Zone has a short growing season (~155 days). Start Zucchini indoors early and use season-extension techniques like row covers and cold frames.

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.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
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Saving Zucchini Seeds

Recommended for Your Garden

🌱
Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

🧪
Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

🏷️
Garden Plant Markers $6-12

Keep your garden organized with durable, weather-resistant plant labels.

Related Plants

Frequently Asked Questions

When should I plant Zucchini in Zone 4b?

In Zone 4b, plan your Zucchini planting around the average last frost date of May 1. Start seeds indoors around March 20. Direct sow outdoors around May 15. Transplant seedlings around May 22.

Can Zucchini grow in Zone 4b?

Yes, Zucchini can grow well in Zone 4b, hardy in USDA zones 3a through 11b. Zone 4b has a growing season of approximately 155 days, which is sufficient for Zucchini (45-60 days to maturity).

When can I harvest Zucchini in Zone 4b?

In Zone 4b, expect to harvest Zucchini from July 10 – September 4. Zucchini takes 45-60 days from planting to harvest.

What is the last frost date for Zone 4b?

The average last spring frost in Zone 4b is around May 1, and the first fall frost is around October 3. This gives a growing season of approximately 155 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Zucchini?

Good companion plants for Zucchini include Corn, Green Beans, Basil, Borage. These companions can help with pest control, pollination, and nutrient sharing.

🌱

Your Free Printable Garden Planner

A 24-page printable planner tailored to your zone. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — 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.