When to Plant Sweet Corn
Published: April 24, 2026
Direct sow after last frost when soil reaches 60°F. Plant in blocks of at least 4 rows for wind pollination. Succession plant every 2 weeks for continuous harvest.
When to plant sweet corn
- Direct sow outdoors: 1 week after last frost
- Minimum soil temperature: 60°F
- Days to harvest: 65–90 days
- Sun requirement: Full sun (8+ hours)
- Spacing: 12 inches apart
- Water: 1.5 inches per week
- Fall crop: No — single spring/summer crop only
⚠ Direct sow corn after last frost when soil reaches 60°F. Plant in blocks of at least 4 rows for pollination. Succession plant every 2 weeks for continuous harvest.
Growing Tips for Sweet Corn
- •Plant in blocks of at least 4 rows × 4 plants, not single rows — corn is wind-pollinated and single rows produce deformed ears.
- •Sow successively every 2 weeks until 90 days before first fall frost for continuous harvest through summer.
- •Side-dress with nitrogen when plants are knee-high and again at tasseling — corn is an extremely heavy feeder.
- •Test for ripeness by puncturing a kernel: clear liquid is under-ripe, milky liquid is perfect, pasty is over-ripe.
Companion Planting for Sweet Corn
✅ Plant sweet corn with
- • Bush Bean
- • Pumpkin
- • Squash
- • Cucumber
- • Pea
❌ Avoid planting near
- • Tomato
- • Celery
Common Sweet Corn Pests and Problems
Regional pest pressure varies — see your state guide below for state-specific pest calendars and treatment timing.
Sweet Corn Planting Dates by State
Select your state for exact sow and transplant dates based on local frost calendars.
Frequently Asked Questions
When do I plant sweet corn?
Direct sow sweet corn 1 week after your last frost date, once soil temperature reaches 60°F. In Zones 3–5 this is late May to early June; in Zones 7–9 it is mid-April to early May. Corn does not transplant — always direct sow. Cold soil below 55°F causes seed rot and poor germination.
How many corn plants do I need?
Each corn plant produces only 1–2 ears, so you need about 15 plants per person for a single meal of fresh corn. Plant in blocks of at least 4 rows × 4 plants (16 plants minimum) to ensure good pollination. For a season-long harvest, make 3 successive plantings spaced 2 weeks apart.
Why do I need to plant corn in a block?
Corn is wind-pollinated — pollen falls from the tassels at the top of each plant onto the silks of ears on nearby plants. Single long rows do not pollinate well because pollen misses the silks, resulting in ears with only a few kernels. A compact block of at least 4 × 4 plants ensures good kernel development on every ear.
When is corn ready to pick?
Sweet corn is ready about 20 days after silks appear and turn brown. Pull back the husk slightly and puncture a kernel: clear liquid is too early, milky liquid is perfect, and thick pasty liquid is overripe. Harvest in the morning when sugars are highest, and cook or refrigerate within a few hours for best flavor.
What should I plant with corn?
The Three Sisters — corn, beans, and squash — is the classic companion planting. Beans climb the corn stalks and fix nitrogen that corn needs; squash spreads across the ground shading out weeds. Peas, cucumbers, and nasturtiums also do well. Avoid tomatoes (share the same pest, corn earworm) and celery.