How long is the growing season in Zone 4b?

Zone 4b has an average growing season of 137 frost-free days.

Zone 4b Planting Schedule

Q: What are the frost dates for Zone 4b?

In Zone 4b, the average last spring frost is May 13th and the average first fall frost is Sep 27th.

Q: When is the best time to start seeds indoors in Zone 4b?

In Zone 4b, start seeds indoors 6–8 weeks before your average last spring frost (around May 13th). The exact timing varies by crop — check the planting schedule above for crop-specific indoor seed start dates.

Last spring frost: May 13th

First fall frost: Sep 27th

Growing season: 137 days

All Zones Zone 4b Save Garden

Action Plan: October in Zone 4b

Expert Note

In Zone 4b during October, keep harvesting before cold nights slow growth. Water early in the day and mulch lightly to steady soil moisture; watch for late-season fungal spots after cool, damp weather.

The Harvest

Prioritize picking ripe fruit from Tomato and Bell Pepper before nights drop too low. Continue harvesting hot peppers like Tabasco and Orange Habanero as they color up, and pull any remaining Eggplant fruit before plants stall.

Planting Schedule

Add crops from the list below to build your planting schedule.

Crop	Indoor Start	Transplant / Sow	Harvest Window
Artichoke	Feb 18th	Apr 29th	Sep 26th – Sep 27th
Giant Red Celery	Feb 18th	Jun 24th	Sep 22nd – Sep 27th
Green Sleeves	Feb 18th	Jun 24th	Sep 22nd – Sep 27th
Gros Vert de Laon	Feb 18th	May 6th	Aug 4th – Sep 27th
Kojak	Feb 18th	Apr 29th	Aug 27th – Sep 27th
Verina	Feb 18th	Apr 1st	Jul 10th – Sep 27th
African Sunset	Mar 4th	May 13th	Aug 11th – Sep 27th
Alabaster	Mar 4th	May 6th	Sep 3rd – Sep 27th
Albin	Mar 4th	May 6th	Sep 3rd – Sep 27th
Amsterdam	Mar 4th	May 6th	Jul 30th – Sep 27th
Amsterdam Cutting	Mar 4th	May 13th	Jul 22nd – Sep 27th
Amsterdam Seasoning	Mar 4th	May 6th	Jul 15th – Sep 27th
Apollo	Mar 4th	May 6th	Sep 3rd – Sep 27th
Artichaut de Nice	Mar 4th	May 6th	Sep 3rd – Sep 27th
Artichoke de Marseille	Mar 4th	Jun 24th	Sep 22nd – Sep 27th
Atlas Angel	Mar 4th	May 6th	Jul 15th – Sep 27th
Baby Artichoke	Mar 4th	May 6th	Jul 30th – Sep 27th
Balder	Mar 4th	May 13th	Aug 26th – Sep 27th
Bandit	Mar 4th	May 6th	Sep 3rd – Sep 27th
Beijing White	Mar 4th	May 6th	Jul 25th – Sep 27th
Bing Select	Mar 4th	Apr 29th	Jul 8th – Sep 27th
Blue Solaise	Mar 4th	May 6th	Aug 24th – Sep 27th
Bordeaux	Mar 4th	May 13th	Jul 27th – Sep 27th
Bullseye Salmon	Mar 4th	May 6th	Jul 15th – Sep 27th
Cabernet	Mar 4th	May 6th	Aug 24th – Sep 27th
Carmen F1	Mar 4th	May 6th	Aug 19th – Sep 27th
Cascade Blue	Mar 4th	May 13th	Jul 22nd – Sep 27th
Catanese	Mar 4th	Jul 8th	Nov 5th – Sep 27th
Celebration	Mar 4th	Apr 29th	Jul 18th – Sep 27th
Celeriac	Mar 4th	Apr 29th	Jul 28th – Sep 27th

Frequently Asked Questions

What are the frost dates for Zone Zone 4b?

In Zone Zone 4b, the average last spring frost is May 13th and the average first fall frost is Sep 27th.

When is the best time to start seeds indoors in Zone Zone 4b?

The best time to start most seeds indoors is 6 to 8 weeks before your last spring frost date of May 13th.

How long is the growing season in Zone Zone 4b?

Zone Zone 4b has a growing season of approximately 137 days.