When to Plant Milk Thistle in North Dakota
North Dakota spans USDA hardiness 3b to 4b (zones 3b to 4b on this page). Plant milk thistle 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
Milk Thistle planting calendar for North Dakota, Zone 3b
Average last spring frost
May 20
Average first fall frost
September 15
Direct sow
Jun 3
Milk Thistle needs about 150 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) →
Milk Thistle planting calendar for North Dakota, Zone 4a
Average last spring frost
May 15
Average first fall frost
September 20
Direct sow
May 29
Milk Thistle needs about 150 days to mature — longer than Zone 4a typically stays frost-free, so it likely won't reliably ripen there outdoors without a head start indoors or season extension. Full zone 4 guide (both 4a and 4b) →
Milk Thistle planting calendar for North Dakota, Zone 4b
Average last spring frost
May 10
Average first fall frost
September 25
Direct sow
May 24
Milk Thistle needs about 150 days to mature — longer than Zone 4b typically stays frost-free, so it likely won't reliably ripen there outdoors without a head start indoors or season extension. Full zone 4 guide (both 4a and 4b) →
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 milk thistle in the HomeSown library. Tap any for its full grow guide.
Common problems with milk thistle
What to watch for, with identification and treatment for each
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