Iceberg Lettuce Seeds (Kabotsha)

Iceberg lettuce (Kabotsha) is the classic crisphead type, growing into a firm, compact, tightly packed head of pale leaves. Its appeal is all about texture: cool, ultra-crunchy leaves with a clean, mild and refreshing flavour that stays light rather than bitter when harvested at the right time. This crispness makes it the go-to lettuce for crunchy salads, sandwiches, burgers and wraps, holding its bite even when shredded.

Planting

Iceberg is a cool-season crop that should be timed to mature before hot weather, as it does not tolerate heat well. In Egypt, the mild winter is the natural season for it: in the Nile Delta, the main sowing window runs roughly from late September through February, with successive sowings every 2 to 3 weeks for a continuous harvest, while the December to January core gives the most reliable hearting because temperatures sit near the ideal cool range. In Upper Egypt (Aswan and Luxor), shift the window later and shorter, roughly November through January, to avoid lingering autumn heat and warm spells that trigger early bolting. Avoid sowing from May to September, when soil temperatures routinely exceed 27 degrees C, causing poor germination and rapid bolting. Sow shallowly, about 0.6 to 1.3 cm deep, and cover only lightly because lettuce seed needs light to germinate. Seeds germinate best at about 13 to 18 degrees C (optimum around 16 to 20 degrees C); germination is poor or slow below 10 degrees C or above roughly 24 to 27 degrees C. During any warm spell, sow in the evening, water with cold water and provide shade to cool the soil. Space crisphead plants about 30 to 38 cm apart in the row, with rows roughly 45 to 75 cm apart. You can also start head lettuce indoors 3 to 4 weeks before field planting, then harden off by reducing water and temperature for 2 to 3 days before transplanting; using 3 to 4 week old transplants avoids the need to thin. If you direct-sow, thin seedlings while small to the final spacing, clipping unwanted seedlings with shears rather than pulling them.

Fertilizing

Lettuce has a medium-high nutrient demand, so incorporate compost or organic matter before planting. Apply a complete balanced 10-10-10 NPK fertilizer at about 1 kg per 9.3 square metres before planting, then side-dress with nitrogen when plants are around 10 cm tall, at roughly 0.45 kg per 7.6 m of row. Lettuce grown in fertile ground generally needs no extra feeding, while container-grown plants only need a general-purpose liquid feed every two weeks in summer.

Care

Iceberg grows well in full sun in the cooler months but tolerates partial shade with 4 to 6 hours of direct light per day; light shade during the hottest part of the day helps prevent bolting. Keep the soil consistently moist to promote rapid growth and prevent bolting, providing about 2.5 cm of water per week (more on sandy soils). Use frequent, light watering and avoid overwatering, which encourages root and leaf disease; water overhead in the morning, and note that containers may need daily watering in warm weather. Watch for common pests such as aphids (including root aphids), cutworms, slugs and snails, flea beetles, and leafhoppers, which transmit aster yellows. Common diseases include downy mildew, which spreads in cool damp weather, grey mould and lettuce mosaic virus; floating row covers help exclude pests, and avoiding overhead watering late in the day reduces disease. Crisphead is ready when it forms a compact, firm head, typically around 60 to 70 days. Harvest in cool weather and earlier rather than later, since heat and over-maturity make the leaves bitter and prompt bolting.