When to Plant Marshmallow in Iowa
Iowa spans USDA hardiness 4b to 6a (zones 4b to 6a on this page). Plant marshmallow 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
Marshmallow planting calendar for Iowa, Zone 4b
Average last spring frost
May 10
Average first fall frost
September 25
Start seeds indoors
Mar 15
Transplant outdoors
May 24
Projected first harvest
Sep 21
Marshmallow is ready to harvest in about 120 days. Full zone 4 guide (both 4a and 4b) →
Marshmallow planting calendar for Iowa, Zone 5a
Average last spring frost
May 5
Average first fall frost
October 1
Start seeds indoors
Mar 10
Transplant outdoors
May 19
Projected first harvest
Sep 16
Marshmallow is ready to harvest in about 120 days. Full zone 5 guide (both 5a and 5b) →
Marshmallow planting calendar for Iowa, Zone 5b
Average last spring frost
April 30
Average first fall frost
October 5
Start seeds indoors
Mar 5
Transplant outdoors
May 14
Projected first harvest
Sep 11
Marshmallow is ready to harvest in about 120 days. Full zone 5 guide (both 5a and 5b) →
Marshmallow planting calendar for Iowa, Zone 6a
Average last spring frost
April 25
Average first fall frost
October 10
Start seeds indoors
Feb 28
Transplant outdoors
May 9
Projected first harvest
Sep 6
Marshmallow is ready to harvest in about 120 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
1 variety of marshmallow in the HomeSown library. Tap any for its full grow guide.
Common problems with marshmallow
What to watch for, with identification and treatment for each
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