When to Plant Butternut Squash in Montana
Montana spans USDA hardiness 3b to 6b (zones 3b to 6b on this page). Plant butternut squash by your local frost date, not the calendar — pick your zone below for exact start-indoors, transplant, and harvest dates.
Jump to: Zone 3b · Zone 4a · Zone 4b · Zone 5a · Zone 5b · Zone 6a · Zone 6b
Butternut Squash planting calendar for Montana, Zone 3b
Average last spring frost
May 20
Average first fall frost
September 15
Start seeds indoors
Apr 29
Transplant outdoors
Jun 3
Butternut Squash needs about 105 days to mature — longer than Zone 3b typically stays frost-free, so it likely won't reliably ripen there outdoors without a head start indoors or season extension. Full zone 3 guide (both 3a and 3b) →
Butternut Squash planting calendar for Montana, Zone 4a
Average last spring frost
May 15
Average first fall frost
September 20
Start seeds indoors
Apr 24
Transplant outdoors
May 29
Projected first harvest
Sep 11
Butternut Squash is ready to harvest in about 105 days. Full zone 4 guide (both 4a and 4b) →
Butternut Squash planting calendar for Montana, 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
Sep 6
Butternut Squash is ready to harvest in about 105 days. Full zone 4 guide (both 4a and 4b) →
Butternut Squash planting calendar for Montana, 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
Sep 1
Butternut Squash is ready to harvest in about 105 days. Full zone 5 guide (both 5a and 5b) →
Butternut Squash planting calendar for Montana, 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
Aug 27
Butternut Squash is ready to harvest in about 105 days. Full zone 5 guide (both 5a and 5b) →
Butternut Squash planting calendar for Montana, 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
Aug 22
Butternut Squash is ready to harvest in about 105 days. Full zone 6 guide (both 6a and 6b) →
Butternut Squash planting calendar for Montana, Zone 6b
Average last spring frost
April 20
Average first fall frost
October 15
Start seeds indoors
Mar 30
Transplant outdoors
May 4
Projected first harvest
Aug 17
Butternut Squash is ready to harvest in about 105 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 butternut squash in the HomeSown library. Tap any for its full grow guide.
Common problems with butternut squash
What to watch for, with identification and treatment for each
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