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Growing Iceberg Crisphead Lettuce in the Vegetable Garden

Iceberg lettuce is a cool-season crop that performs best when sown in early spring or late summer for a fall harvest. Direct sow seeds 0.125 inch deep as soon as the soil can be worked, or start transplants indoors 4 to 6 weeks before your last frost date and move them outside once nighttime temperatures are consistently above 28 F. Thin or transplant to 12 to 14 inches apart in rows 18 inches apart — adequate spacing is essential for good head development and helps reduce fungal pressure. Lettuce germinates best with soil temperatures between 40 and 75 F; avoid sowing in hot soils above 80 F, as germination will drop sharply.

Keep the soil consistently moist throughout the growing season — shallow roots make lettuce sensitive to drought stress, which can cause tipburn and bitterness. Water at the base of plants rather than overhead to reduce disease pressure. Side-dress with a balanced fertilizer 3 to 4 weeks after transplanting if growth appears slow. In warmer climates, shade cloth rated at 30 to 40 percent can extend the harvest window by several weeks. Mulching around plants helps moderate soil temperature and retain moisture.

Harvesting Iceberg Crisphead Lettuce

Iceberg lettuce is ready to harvest when the head feels firm and dense when gently squeezed — loose or soft heads need more time. Cut the head at the base with a sharp knife just below the lowest leaves, typically 70 to 79 days after seeding. Harvest in the morning when heads are cool and fully hydrated for the best texture and shelf life. Unwashed heads can be stored in a loosely sealed bag in the refrigerator for up to 2 weeks. Avoid harvesting after extended heat, as heads may be bitter or show signs of early bolting.

About Iceberg Crisphead Lettuce Garden Seeds

Iceberg lettuce has been a staple of the American table since the early 20th century, when refrigerated rail cars made it possible to ship fresh heads coast to coast — packed in ice, which gave the variety its enduring common name.

The variety belongs to the crisphead class of lettuce, characterized by tightly folded, overlapping leaves that form a dense, ball-shaped head with a crisp texture and high water content.

While often overshadowed in culinary circles by more flavorful greens, Iceberg remains one of the top-selling vegetable crops in the United States and the backbone of countless salads, wedge presentations, sandwiches, and burger toppings.

Tips From Our Gardeners

If your Iceberg heads are coming in loose instead of tight and firm, the most common culprit is warm soil temperature, not variety failure. Try sowing 3 to 4 weeks earlier in spring, or switch to a fall planting timed so heads mature before your first frost. Cool nights are what trigger Iceberg to close up and head properly — they make all the difference.

- Jerry Sawyer, True Leaf Market Writer

Iceberg Crisphead Lettuce Seeds Per Package:

• 1 g Packet - Approximately 565 Seeds
• 1 oz - Bulk - Approximately 16,000 Seeds
• 4 oz - Bulk - Approximately 64,000 Seeds
• 1 lb - Wholesale - Approximately 256,000 Seeds
• 5 lb - Wholesale - Approximately 1,280,000 Seeds
• 25 lb - Wholesale - Approximately 6,400,000 Seeds

Iceberg Crisphead Lettuce seeds are available for Fast Free Shipping on qualifying orders.