When to plant sweet corn
Sweet corn is sown directly outdoors after the last frost, once soil reaches at least 60°F (65°F for super-sweet varieties, which are more prone to rotting). It is wind-pollinated, so plant in blocks of at least four short rows rather than one long row.
Stagger sowings two weeks apart, or plant early, mid and late varieties on the same day, to stretch the harvest.
Sweet cornZea mays var. saccharata
- Sow seed outside
- 1–3 weeks after last frost
- Frost
- Frost-tender: killed at 32°F
- Soil temp
- 60°F (16°C) or warmer
- Depth
- 1–2 in
- Spacing
- 12 in apart, rows 30 in · 1 per square foot
- Harvest
- 65–95 days
Your dates for sweet corn
Tips for growing sweet corn
- Block planting ensures pollen from the tassels falls onto the silks; poor pollination gives gappy cobs.
- Keep super-sweet (sh2) types at least 250 feet from other corn or they cross and turn starchy.
- Harvest when silks are brown and kernels squirt milky juice when pressed.
Choosing neighbours? See companion plants for sweet corn. Working out how many fit? Use the spacing calculator.
Sweet corn: common timing questions
How late can I plant sweet corn?
Until about 80–100 days before your first fall frost, depending on the variety.
Why plant corn in blocks?
Corn is wind-pollinated. Blocks let pollen fall onto neighbouring silks; single rows often leave cobs with missing kernels.