Growing sweet potatoes in zone 4
Sweet potatoes grow from slips (rooted cuttings), not seed — order them or sprout your own from a store tuber. Plant well after frost into warm soil, then dig before soil temps drop in fall and cure for sweetness.
Zone 4 covers northern Plains, northern New England, much of Montana and Wyoming — about 150 frost-free days — most vegetables work, long-season melons are a stretch. Zone dates are medians: frost timing varies within a zone with elevation and terrain, so treat these windows as a solid default and refine them with your own city’s dates below.
Make it local
These windows use zone 4's typical frost dates (last frost ~May 5, first frost ~Oct 1). For windows computed from your frost dates, run the ZIP code frost lookup and open the planting calendar — it remembers your city. The seed starting scheduler turns the whole seed rack into one printable, date-sorted list.
Frequently asked questions
When do I plant sweet potatoes in zone 4?
Transplant May 19 – Jun 2, counted from zone 4's typical last frost around May 5. It has no frost tolerance — a late frost after planting means covering it or replanting.
Can I direct sow sweet potatoes in zone 4?
Not usefully in zone 4 — sweet potatoes needs more growing time than direct sowing allows, which is why it's raised from transplants .