Jericho Romaine Lettuce

Lactuca sativa

Approximately ~ 150 seeds per packet

Packed for 2026

Days to Maturity: 55–65 days

Origins and History of Domestication

Jericho Lettuce is a romaine, or cos, type of Lactuca sativa, the cultivated lettuce species belonging to the Asteraceae family. Lettuce has an ancient history centered in the Mediterranean, Near East, and Southwest Asia, where wild relatives such as Lactuca serriola contributed to the development of cultivated lettuce. Evidence of lettuce cultivation extends back thousands of years, with ancient Egyptians depicting lettuce in agricultural and religious contexts. Over generations, farmers selected plants for larger, less bitter leaves, reduced spines, slower bolting, and more desirable growth habits. These selections eventually produced the major lettuce groups familiar today, including romaine/cos, butterhead, crisphead, loose-leaf, and stem lettuce.

Spread and Diversification

Cultivated lettuce spread from the eastern Mediterranean and Near East through Europe, North Africa, and Asia and eventually to the Americas. Romaine lettuce became especially associated with Mediterranean agriculture and was selected for its upright growth, elongated leaves, crisp midribs, and ability to form tall heads. Jericho is an Israeli-developed romaine variety, selected for its ability to perform particularly well under warm and relatively dry growing conditions. It is valued by gardeners and small-scale growers because it combines the characteristic crunch of romaine with comparatively good heat tolerance and resistance to premature bolting. Although commonly marketed within heirloom and open-pollinated seed collections, it is more accurately described as an open-pollinated traditional-type cultivar rather than an ancient heirloom.

Appearance and Characteristics

Jericho produces attractive, tall, upright heads composed of elongated bright- to medium-green leaves. The leaves have prominent pale-green to whitish midribs and a crisp yet tender texture. Mature plants can form substantial romaine heads, particularly when supplied with adequate moisture and fertility. The inner leaves become more tightly clustered and tender as the head develops. Jericho's most notable characteristic is its heat tolerance, making it useful for extending romaine production into warmer weather when many lettuce varieties quickly become bitter or bolt. It nevertheless remains a cool-season vegetable and produces its highest-quality leaves under moderate temperatures.

Culinary Uses

Jericho Lettuce is an excellent all-purpose romaine. Its crisp leaves and substantial midribs make it especially suitable for Caesar salads, chopped salads, sandwiches, wraps, burgers, and fresh vegetable platters. The sturdy leaves can serve as edible cups or wraps for grains, beans, vegetables, chicken, or other fillings. Romaine can also be lightly grilled, braised, or added briefly to soups and stir-fries. The tender inner leaves are particularly good eaten fresh, while larger outer leaves provide more texture and withstand cooking or grilling well.

Growing Tips and Vegetation Zones

Jericho can be grown as an annual vegetable throughout USDA Zones 3–11, because lettuce's growing season is determined more by temperature than by winter-hardiness zone. In Zones 3–6, sow from spring through early summer and again for a late-summer or fall crop. In Zones 7–8, including the Mid-Atlantic, it performs especially well as an early-spring and fall crop, with succession plantings extending the harvest. In Zones 9–11, it is generally best grown from fall through winter and early spring. Jericho tolerates heat better than many romaines, but prolonged temperatures above roughly 80–85°F can still encourage bolting and bitterness.

Plant in fertile, well-drained soil containing plenty of organic matter, ideally at a soil pH of about 6.0–7.0. Sow seeds approximately ⅛–¼ inch deep, since lettuce seeds require only a light covering of soil. Direct-sow seeds about 1 inch apart and thin plants to approximately 8–12 inches apart for mature heads, with rows approximately 12–18 inches apart. Seeds can also be started indoors about 4–6 weeks before transplanting. Keep the soil consistently moist because irregular watering can reduce leaf quality and contribute to bitterness. In warm weather, afternoon shade, mulch, frequent irrigation, and succession planting can help extend production.

Days to Maturity

Jericho can be harvested as baby lettuce in approximately 25–35 days, depending on growing conditions. Full-sized romaine heads generally mature in approximately 55–65 days from direct seeding, although temperature, daylight, soil fertility, and moisture can affect maturity. Gardeners do not need to wait for a completely mature head; individual leaves can be harvested throughout the plant's development.

Harvesting Guidance

For a continuous harvest, remove the largest outer leaves while allowing the center of the plant to continue growing. Harvest baby leaves when they reach the desired size. For full heads, cut the plant near soil level with a clean knife when the head is well developed, upright, crisp, and firm but before the central stalk begins elongating. Harvesting early in the morning, when plants are fully hydrated and temperatures are cool, generally produces the crispest leaves. During warm weather, monitor plants closely for signs of bolting; harvest promptly if the center begins to elongate because leaf bitterness usually increases as flowering approaches. After harvest, cool the lettuce quickly, remove damaged outer leaves, and refrigerate under high humidity for the best quality and storage life.