Plant Potatoes in Zone 4b
Seed-starting, transplant & harvest dates for USDA Zone 4b
Zone 4b averages 146 frost-free days, running from a last spring frost around May 5 to a first fall frost around September 28. Potatoes needs roughly 90 days from planting out to first harvest, so it uses about 62 percent of that window. Potatoes is a half-hardy crop, which is what decides where in the window it belongs.
Potatoes handles cold soil, so there is no reason to wait for the frost date. Direct sow around Apr 21, roughly 2 weeks before the Zone 4b last frost, as soon as the ground is workable. Sowing at the last frost instead costs you the coolest and best part of the season.
Fall planting: potatoes in Zone 4b
Potatoes has no useful fall window in Zone 4b. A fall potato crop works in zone 8 and warmer, planted in late summer from certified seed pieces that have broken dormancy.
A fall potato crop works in zone 8 and warmer, planted in late summer from certified seed pieces that have broken dormancy.
Fall dates are counted backward from the Zone 4b average first frost, not forward from a sowing date. See the fall planting calendar by zone for the full method.
Spring vs fall potatoes in Zone 4b
| Planting | Sow or start | In the ground | Harvest |
|---|---|---|---|
| Spring | Apr 21 | Apr 21 | Jul 20 |
| Fall | — | — | — |
Potatoes in nearby zones
Further reading on potatoes
- Last frost date and what to plant before it
Why potatoes can go out before your last frost, and how far before.
- Best raised garden beds for beginners
Loose, deep soil is most of what root crops need.
- Row covers vs frost blankets
Which cover buys potatoes the extra degrees on a frosty night.
Other crops in Zone 4b
Frequently asked questions
When should I start potatoes in Zone 4b?
Direct sow outdoors around Apr 21.
Can I direct sow potatoes in Zone 4b?
Yes, direct sow around Apr 21.
Can I plant potatoes in the fall in Zone 4b?
Potatoes has no useful fall window in Zone 4b. A fall potato crop works in zone 8 and warmer, planted in late summer from certified seed pieces that have broken dormancy.
Will potatoes survive frost in Zone 4b?
Potatoes is a half-hardy crop and keeps going roughly 10 days past the first light frost in Zone 4b. A row cover or a straw mulch buys more.