Warm-Season Vegetable

When to Plant Corn (Sweet) in New Hampshire

Nothing says summer like fresh sweet corn. Plant in blocks (not rows) for proper pollination.

The Short Answer

In New Hampshire, corn (sweet) planting dates vary by region. In Northern New Hampshire, your average last frost is around May 20 - Jun 5, while Southern New Hampshire sees its last frost around May 1 - May 20. Since corn (sweet) are frost-sensitive, direct sow 2 weeks after your last frost date. Rocky, acidic New England soils. Glacial deposits. Granite bedrock. Raised beds essential in many areas.

New Hampshire Frost Dates

Your planting dates depend on which part of New Hampshire you're in. Here are the frost date ranges by region:

Region	Zones	Last Frost (Spring)	First Frost (Fall)
Northern New Hampshire	3b, 4a, 4b	May 20 - Jun 5	Sep 10 - Sep 25
Southern New Hampshire	5a, 5b, 6a	May 1 - May 20	Sep 25 - Oct 10

Corn (Sweet) Planting Schedule for New Hampshire

Northern New Hampshire (Zones 3b, 4a, 4b)

Average last frost: May 20 - Jun 5 · Average first frost: Sep 10 - Sep 25

Direct Sow

2 wks after frost

Southern New Hampshire (Zones 5a, 5b, 6a)

Average last frost: May 1 - May 20 · Average first frost: Sep 25 - Oct 10

Direct Sow

2 wks after frost

Growing Corn (Sweet) in New Hampshire

Corn (Sweet) in New Hampshire's Climate

Sweet corn needs warm soil and warm nights but matures quickly enough for most cold-climate gardens. Direct sow when soil reaches 60°F — typically late May. Choose early varieties (60-65 days) for the shortest seasons. Plant in blocks of at least 4×4 for wind pollination. Raccoons are the universal corn nemesis — electric fencing is the only reliable deterrent.

Soil Considerations for New Hampshire

Rocky, acidic New England soils. Glacial deposits. Granite bedrock. Raised beds essential in many areas. Make sure soil has warmed to at least 60°F before planting corn (sweet) outside.

New Hampshire Climate & Growing Season

Short growing season especially in north. Cold winters. Cool summers. Hardy varieties important. Corn (Sweet) cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.

Growing season length varies across New Hampshire: Northern New Hampshire (3b, 4a, 4b) has a last frost around May 20 - Jun 5, while Southern New Hampshire (5a, 5b, 6a) sees frost end around May 1 - May 20. This difference matters for corn (sweet) — transplant timing shifts by several weeks across the state.

Growing Tips

Plant in blocks of at least 4x4 for wind pollination. Corn is a heavy feeder — amend soil with compost before planting.

Companion Planting

Plant corn (sweet) alongside these companions for better growth:

Beans Squash Melons

Keep corn (sweet) away from:

Tomatoes

The Bottom Line

Corn (Sweet) can be grown successfully across New Hampshire, but your exact planting dates depend on which region you're in. Northern New Hampshire gardeners should plan around a May 20 - Jun 5 last frost, while those in Southern New Hampshire can typically plant earlier. For exact dates based on your zip code, use our free planting date finder.

Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026