When to plant zucchini in zone 3b

In zone 3b, where the last spring frost typically comes around May 17, start zucchini indoors May 11 to 25 and plant out June 8 to 22.

The zone 3b schedule for zucchini

Start seeds indoors: May 11 to 25
Plant out: June 8 to 22
Sow outdoors: June 8 to 22
Soil warm enough (60°F), about: June 8

From the median frost dates of the NOAA stations assigned to the 200 ZIP codes in zone 3b, and the timing recommended by Cooperative Extension guides for zucchini.

Frost risk in zone 3b

Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 3b, the typical last frost ranges from about May 12 in the earliest tenth of ZIP codes to May 29 in the latest tenth, and the first fall frost from September 13 to October 1. For a typical place in the zone:

May 4Risky: a later frost happens in 9 years out of 10
May 17Typical: frost after this date in half of years
May 30Safe: a later frost only 1 year in 10

Zucchini are killed by frost, so if you want to be safe, plant out after the safe date rather than the typical one, or be ready to cover plants on a cold night.

Your dates for zucchini

Set your ZIP code at the top of the page and we will work out when to plant zucchini where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.

Enter your ZIP code

How to grow zucchini All zones Zucchini in zone 3a Zucchini in zone 4a About zone 3b

Sources

Summer Squash (HGIC factsheet) · Clemson Cooperative Extension Home & Garden Information Center
How to Grow Summer and Winter Squash in Your Garden · Utah State University Extension
Growing Squash in Iowa · Iowa State University Extension and Outreach
Summer Squash (Mid-Atlantic Commercial Vegetable Production Recommendations, section F) · University of Maryland Extension
Vegetable Planting Guide (CMG GardenNotes #720) · Colorado State University Extension
Cucumbers, Pumpkins, Squash, and Melons (Fact Sheet 7.609) · Colorado State University Extension
Fall Vegetable Gardening (G1343) · University of Nebraska-Lincoln Extension
Vegetable Gardening in Containers · Texas A&M AgriLife Extension
Florida Vegetable Gardening Guide (VH021), Table 1 · University of Florida IFAS Extension (EDIS)
Vegetable Planting Calendar for Maricopa County (AZ1005) · University of Arizona Cooperative Extension