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When to plant zucchini in zone 4b

In zone 4b, where the last spring frost typically comes around May 8, start zucchini indoors April 30 to May 14 and plant out May 28 to June 11.

The zone 4b schedule for zucchini

Start seeds indoors
April 30 to May 14
Plant out
May 28 to June 11
Sow outdoors
May 28 to June 11
Soil warm enough (60°F), about
May 28

From the median frost dates of the NOAA stations assigned to the 1,164 ZIP codes in zone 4b, and the timing recommended by Cooperative Extension guides for zucchini.

Frost risk in zone 4b

Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 4b, the typical last frost ranges from about May 1 in the earliest tenth of ZIP codes to May 25 in the latest tenth, and the first fall frost from September 22 to October 8. For a typical place in the zone:

  • April 26Risky: a later frost happens in 9 years out of 10
  • May 8Typical: frost after this date in half of years
  • May 22Safe: 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

Zucchini in zone 4b cities

CityTypical last frostStart indoorsPlant out
Rochester, MNApr 30Apr 25 to May 9May 23 to Jun 6
Duluth, MNMay 6May 24 to Jun 7Jun 21 to Jul 5
Lakeville, MNMay 2Apr 26 to May 10May 24 to Jun 7
St. Cloud, MNMay 7Apr 29 to May 13May 27 to Jun 10
Eau Claire, WIMay 8Apr 26 to May 10May 24 to Jun 7
Great Falls, MTMay 19May 22 to Jun 5Jun 19 to Jul 3

How to grow zucchiniAll zonesZucchini in zone 4aZucchini in zone 5aAbout zone 4b

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