When to Plant Summer Squash in Iowa
Iowa spans USDA hardiness 4b to 6a (zones 4b to 6a on this page). Plant summer squash by your local frost date, not the calendar — pick your zone below for exact start-indoors, transplant, and harvest dates.
Jump to: Zone 4b · Zone 5a · Zone 5b · Zone 6a
Summer Squash planting calendar for Iowa, Zone 4b
Average last spring frost
May 10
Average first fall frost
September 25
Start seeds indoors
Apr 19
Transplant outdoors
May 24
Projected first harvest
Jul 13
Most summer squash mature in about 50 days. Full zone 4 guide (both 4a and 4b) →
Summer Squash planting calendar for Iowa, Zone 5a
Average last spring frost
May 5
Average first fall frost
October 1
Start seeds indoors
Apr 14
Transplant outdoors
May 19
Projected first harvest
Jul 8
Most summer squash mature in about 50 days. Full zone 5 guide (both 5a and 5b) →
Summer Squash planting calendar for Iowa, Zone 5b
Average last spring frost
April 30
Average first fall frost
October 5
Start seeds indoors
Apr 9
Transplant outdoors
May 14
Projected first harvest
Jul 3
Most summer squash mature in about 50 days. Full zone 5 guide (both 5a and 5b) →
Summer Squash planting calendar for Iowa, Zone 6a
Average last spring frost
April 25
Average first fall frost
October 10
Start seeds indoors
Apr 4
Transplant outdoors
May 9
Projected first harvest
Jun 28
Most summer squash mature in about 50 days. Full zone 6 guide (both 6a and 6b) →
Not sure which half-zone you're in? Set your ZIP in HomeSown for dates tuned to your exact location.
Varieties to grow
3 varieties of summer squash in the HomeSown library. Tap any for its full grow guide.
Common problems with summer squash
What to watch for, with identification and treatment for each
🌱 Grow summer squash with a calendar built for your exact yard
HomeSown turns your ZIP code into a personalized planting calendar, watering reminders, and pest help. Free to start.
Start your free garden →