When to plant sweet corn in Delaware
Delaware’s average last spring frost is April 14, and the first fall frost typically arrives around October 22 — about 191 frost-free days (USDA zones 7a, 7b). Sweet Corn needs 60–100 days to mature, which fits comfortably within Delaware's growing season.
When to plant sweet corn in Delaware: the short answer
For a spring planting, sow Apr 16 – May 5. Wait until the soil is at least 55°F and frost is over.
Succession sow again in Delaware: May 5 · May 19 · Jun 2 · Jun 16 · Jun 30 · Jul 14 · Jul 28
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow sweet corn in Delaware, step by step
- Prepare the bed. It needs at least six to eight hours of direct sun a day and loose soil at least 24 inches deep, with a pH between 5.8 and 7.0. Dig in compost before planting.
- Sow outdoors (Apr 16 – May 5). Space plants about 10 inches apart in rows 30 inches apart, sowing seed 1.5 inches deep. It is killed by frost, so nothing goes outside until the danger has passed.
- Water and feed. It needs plenty of water; keep the soil evenly moist and never let it dry out.
- Watch for pests and problems. Pests: corn earworm, European corn borer, corn rootworm, raccoons. Diseases and disorders: common smut, common rust, Stewart's wilt.
- Harvest (from about Jun 20 – Jul 30). Sweet Corn takes 60-100 days to reach harvest. Plant in a block of at least 4 short rows, not one long row, or the ears fill unevenly. Keep sugar-enhanced and supersweet types isolated from field corn. Succeed by sowing every 2 weeks or planting early/mid/late varieties together.
Figures come from our crop data; dates use Delaware’s average frost dates. More in the full sweet corn growing guide.
When to plant sweet corn in nearby states
| State | Last frost | Sow |
|---|---|---|
| Delaware (this page) | April 14 | Apr 16 – May 5 |
| New Jersey | April 20 | Apr 22 – May 11 |
| Pennsylvania | May 1 | May 3 – May 22 |
| Maryland | April 14 | Apr 16 – May 5 |
| District of Columbia | April 10 | Apr 12 – May 1 |
| Virginia | April 15 | Apr 17 – May 6 |
| West Virginia | May 5 | May 7 – May 26 |
Questions gardeners in Delaware ask
When is the best time to plant sweet corn in Delaware?
Sow sweet corn in Delaware between April 16 and May 5. That timing is set by Delaware's average last spring frost of April 14.
What is the latest I can plant sweet corn in Delaware?
About August 23. Sweet corn needs at least 60 days to mature, and frost around October 22 ends the season, so later plantings risk being cut short.
When will sweet corn planted in Delaware be ready to harvest?
Planted on time, sweet corn is usually ready from about June 20 to July 30, 60-100 days after sowing.
When is the last frost in Delaware?
On average around April 14, with the first fall frost around October 22 - about 191 frost-free days. Your town may differ by two weeks or more.