Plant Corn in Zone 3b
Seed-starting, transplant & harvest dates for USDA Zone 3b
Zone 3b averages 128 frost-free days, running from a last spring frost around May 13 to a first fall frost around September 18. Corn needs roughly 75 days from planting out to first harvest, so it uses about 59 percent of that window. Corn is a tender crop, which is what decides where in the window it belongs.
Corn resents transplanting and hates cold soil, so direct sow around May 20, after the Zone 3b last frost has passed and the soil has warmed.
Fall planting: corn in Zone 3b
Corn has no useful fall window in Zone 3b. Sweet corn pollinates badly in short, cool autumn days, so a fall planting rarely fills out.
Sweet corn pollinates badly in short, cool autumn days, so a fall planting rarely fills out.
Fall dates are counted backward from the Zone 3b average first frost, not forward from a sowing date. See the fall planting calendar by zone for the full method.
Spring vs fall corn in Zone 3b
| Planting | Sow or start | In the ground | Harvest |
|---|---|---|---|
| Spring | May 20 | May 20 | Aug 3 |
| Fall | — | — | — |
Corn in nearby zones
Further reading on corn
- Soil temperature for planting seeds
The soil temperature corn needs before it will germinate.
- Companion planting chart
What to plant with corn and what to keep away from it.
Other crops in Zone 3b
Frequently asked questions
When should I start corn in Zone 3b?
Direct sow outdoors around May 20.
Can I direct sow corn in Zone 3b?
Yes, direct sow around May 20.
Can I plant corn in the fall in Zone 3b?
Corn has no useful fall window in Zone 3b. Sweet corn pollinates badly in short, cool autumn days, so a fall planting rarely fills out.
Will corn survive frost in Zone 3b?
No. Corn is a tender crop and a single light frost ends it, so every Zone 3b planting has to finish before the average first frost.