Lettuce

Growing Lettuce in Zone 4b

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

May 7Last spring frost
October 3First fall frost
about 149 daysGrowing season
−30 to −20°FWinter low

Your planting timeline

  1. Direct sowonce soil warms, around May 7
  2. Harvestabout 30–70 days from transplant

Best varieties for zone 4b

Choose quick-maturing, frost-tolerant varieties such as Buttercrunch, Tom Thumb, and Black-Seeded Simpson that handle chilly spring nights.

Growing notes

Lettuce has shallow roots and high water content, so it wants steady, even moisture — roughly 1 to 1.5 inches per week, delivered as light, frequent waterings rather than occasional soakings. Let the bed dry out and growth stalls while the leaves turn tough and bitter and bolting speeds up. Water at the base in the morning so foliage dries quickly, which discourages downy mildew and rot in the dense, tender leaves. A thin mulch of straw conserves moisture and keeps soil cool around the roots. Container and raised-bed lettuce dries fastest and may need watering daily in warm weather. Consistency is everything: erratic wet-then-dry swings produce bitter, stringy leaves.

Recommended supplies

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