How long is the growing season in Zone 4a?

Zone 4a has an average growing season of 132 frost-free days.

Zone 4a Planting Schedule

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

In Zone 4a, the average last spring frost is May 15th and the average first fall frost is Sep 24th.

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

In Zone 4a, start seeds indoors 6–8 weeks before your average last spring frost (around May 15th). The exact timing varies by crop — check the planting schedule above for crop-specific indoor seed start dates.

Last spring frost: May 15th

First fall frost: Sep 24th

Growing season: 132 days

All Zones Zone 4a Save Garden

Action Plan: August in Zone 4a

Expert Note

In August, keep soil evenly moist and mulch to moderate swings between hot days and cooler nights. Watch for late-season pests like aphids and squash bugs, and remove diseased leaves early to slow spread. Water at the base in the morning.

Seed & Soil

Use August to direct sow and start quick, heat-tolerant crops like Green Basil and Italian Large Leaf for steady leaf harvest. Add fast ground coverage with Zucchini and Lemon Cucumber if you have warm soil. For a longer season, transplant Tomato only if you can protect from early cool snaps.

The Harvest

Harvest Beauregard and Bonbon as they mature, and cure them in a warm, dry spot for best storage. Keep picking Marketmore 76 and Lemon Cucumber regularly to maintain production. Start pulling ripe Sweet Meat and check Buttercup squash for firm skin before storing.

Planting Schedule

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

Crop	Indoor Start	Transplant / Sow	Harvest Window
Artichoke	Feb 20th	May 1st	Sep 28th – Sep 24th
Giant Red Celery	Feb 20th	Jun 26th	Sep 24th – Sep 24th
Green Sleeves	Feb 20th	Jun 26th	Sep 24th – Sep 24th
Gros Vert de Laon	Feb 20th	May 8th	Aug 6th – Sep 24th
Kojak	Feb 20th	May 1st	Aug 29th – Sep 24th
Verina	Feb 20th	Apr 3rd	Jul 12th – Sep 24th
African Sunset	Mar 6th	May 15th	Aug 13th – Sep 24th
Alabaster	Mar 6th	May 8th	Sep 5th – Sep 24th
Albin	Mar 6th	May 8th	Sep 5th – Sep 24th
Amsterdam	Mar 6th	May 8th	Aug 1st – Sep 24th
Amsterdam Cutting	Mar 6th	May 15th	Jul 24th – Sep 24th
Amsterdam Seasoning	Mar 6th	May 8th	Jul 17th – Sep 24th
Apollo	Mar 6th	May 8th	Sep 5th – Sep 24th
Artichaut de Nice	Mar 6th	May 8th	Sep 5th – Sep 24th
Artichoke de Marseille	Mar 6th	Jun 26th	Sep 24th – Sep 24th
Atlas Angel	Mar 6th	May 8th	Jul 17th – Sep 24th
Baby Artichoke	Mar 6th	May 8th	Aug 1st – Sep 24th
Balder	Mar 6th	May 15th	Aug 28th – Sep 24th
Bandit	Mar 6th	May 8th	Sep 5th – Sep 24th
Beijing White	Mar 6th	May 8th	Jul 27th – Sep 24th
Bing Select	Mar 6th	May 1st	Jul 10th – Sep 24th
Blue Solaise	Mar 6th	May 8th	Aug 26th – Sep 24th
Bordeaux	Mar 6th	May 15th	Jul 29th – Sep 24th
Bullseye Salmon	Mar 6th	May 8th	Jul 17th – Sep 24th
Cabernet	Mar 6th	May 8th	Aug 26th – Sep 24th
Carmen F1	Mar 6th	May 8th	Aug 21st – Sep 24th
Cascade Blue	Mar 6th	May 15th	Jul 24th – Sep 24th
Catanese	Mar 6th	Jul 10th	Nov 7th – Sep 24th
Celebration	Mar 6th	May 1st	Jul 20th – Sep 24th
Cherokee Sunset	Mar 6th	May 15th	Jul 24th – Sep 24th

Frequently Asked Questions

What are the frost dates for Zone Zone 4a?

In Zone Zone 4a, the average last spring frost is May 15th and the average first fall frost is Sep 24th.

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

The best time to start most seeds indoors is 6 to 8 weeks before your last spring frost date of May 15th.

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

Zone Zone 4a has a growing season of approximately 132 days.