Sweet Corn

Growing Sweet Corn in Zone 4a

A complete, zone-4a timeline for Sweet Corn — when to start, transplant, and harvest, tuned to this zone's typical frost dates (Minneapolis, MN; Bangor, ME).

May 17Last spring frost
September 23First fall frost
about 129 daysGrowing season
−30 to −20°FWinter low

Your planting timeline

  1. Direct sowonce soil warms, around May 17
  2. Harvestabout 60–100 days days from transplant

Best varieties for zone 4a

Fast early se varieties such as 'Sugar Buns' or 'Trinity' reliably finish before fall frost in a brief season.

Growing notes

Sweet corn needs steady, even moisture — about 1 to 1.5 inches of water per week — and is especially thirsty during two windows: when it's putting up tall growth, and from tasseling through ear fill. Water deeply at the base rather than overhead to keep the foliage dry and reduce disease, soaking the root zone two or three times a week rather than a daily sprinkle. Drought stress at pollination causes missing kernels and stunted ears, the most common cause of a poor harvest. Mulch around the block to hold moisture and even out the supply. In sandy soil that drains fast, water more often; in heavy clay, water deeply but less frequently to avoid waterlogging.

Recommended supplies

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