Plant Corn in Zone 9b
Seed-starting, transplant & harvest dates for USDA Zone 9b
Zone 9b averages 298 frost-free days, running from a last spring frost around February 15 to a first fall frost around December 10. Corn needs roughly 75 days from planting out to first harvest, so it uses about 25 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 Feb 22, after the Zone 9b last frost has passed and the soil has warmed. At 75 days to harvest, a 298-day Zone 9b season has room for about 3 sowings, so stagger them rather than planting everything at once.
Fall planting: corn in Zone 9b
Corn has no useful fall window in Zone 9b. 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 9b 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 9b
| Planting | Sow or start | In the ground | Harvest |
|---|---|---|---|
| Spring | Feb 22 | Feb 22 | May 8 |
| 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 9b
Frequently asked questions
When should I start corn in Zone 9b?
Direct sow outdoors around Feb 22.
Can I direct sow corn in Zone 9b?
Yes, direct sow around Feb 22.
Can I plant corn in the fall in Zone 9b?
Corn has no useful fall window in Zone 9b. Sweet corn pollinates badly in short, cool autumn days, so a fall planting rarely fills out.
Will corn survive frost in Zone 9b?
No. Corn is a tender crop and a single light frost ends it, so every Zone 9b planting has to finish before the average first frost.
How many plantings of corn fit in a Zone 9b season?
About 3. Zone 9b averages 298 frost-free days and corn needs roughly 75 days plus a couple of weeks of turnaround, so sowing every 45 days keeps a supply coming.