Stem lettuce is a fast-growing, half-hardy annual. It is best grown in spring and late summer, as prolonged heat encourages the plants to bolt. Thanks to its combination of edible leaves and a delicious, crisp stem, stem lettuce is a unique and versatile vegetable that is becoming increasingly popular in both Asian and European cuisine. Also known as asparagus lettuce, celtuce, Chinese stem lettuce, and by its Chinese names wosun or woju, this unusual lettuce originated in Asia. Unlike ordinary lettuce, it is grown not only for its leaves but especially for its thick, juicy stem, which is eaten as a vegetable. This makes stem lettuce a highly versatile crop, providing two different harvests from a single plant. The young leaves have a firm texture and a fresh, slightly bitter flavour reminiscent of romaine lettuce or chicory. They are delicious as the base for salads or can be lightly braised, stir-fried or used in soups, omelettes and savoury tarts, much like spinach. As the plant matures, the leaves become slightly more bitter, making them particularly suitable for cooked dishes. Like other lettuce varieties, stem lettuce is rich in vitamins A, B-complex, C and K and contains important minerals such as calcium, potassium, magnesium, phosphorus and iron. It is also a good source of dietary fibre and is naturally low in calories, making it an excellent addition to a healthy, balanced diet.
Both the leaves and the stem can be harvested. Young leaves can be picked regularly throughout the growing season. The stem is ready to harvest when it is approximately 20 - 35 cm long and 3 - 5 cm thick. Do not leave it too long, as an overgrown stem may become fibrous and woody. Once peeled, the stem is ready to use immediately. The real delicacy, however, is the stem. After removing the tough outer skin, the crisp, juicy, pale green flesh is revealed. It has a fresh, slightly sweet and subtly nutty flavour, often described as a combination of asparagus, cucumber, celery and artichoke. The stem retains its pleasant crunch even after cooking. The peeled stem can be sliced, diced or cut into strips for stir-fries, curries, noodle dishes and rice dishes. It is also delicious when briefly blanched, steamed, grilled or pan-fried. Raw, it can be enjoyed in salads, as a crunchy snack or as part of fresh vegetable platters. It is also ideal for fermenting or pickling, as is common in Asian cuisine. Stem lettuce pairs beautifully with garlic, ginger, spring onions, sesame oil, soy sauce, oyster sauce, rice vinegar and chilli peppers. It also complements chicken, duck, pork, beef, prawns, tofu and tempeh. Nuts such as cashews, peanuts and sesame seeds enhance its subtle nutty flavour. Fresh herbs including coriander, chives, parsley and mint add an extra touch of freshness. Non hardy annual. Height: 40 - 60 cm. Width: 20 - 30 cm.
Outdoor sowing under glass: March - April
Outdoor sowing: April - June
Germination: 7 - 14 days
Germination temp.: 6 - 18 °C
Sowing depth: shallow - ½ cm
Planting distance: 35 - 40 cm
Distance between the rows: 40 cm
Planting postition: sunny - semi-shade
Days till harvest leaves: 35 - 40
Days till harvest stem: 56 - 70
Sow outdoors under protection (cold greenhouse, cold tray) from March. Sow shallowly in separate pots or in seed trays with separate cells to make transplanting easier. Use a well-moistened sowing medium. Cover the seeds with a very thin layer as this is a light germinator. Keep the temperature as even as possible and don't let the temperature drop especially at night. Plant out the seedlings 3 - 4 weeks after germination in a pre-fertilised, sunny spot with good drainage. Keep the plantlets moist and weed-free. Keep 35 - 40 cm space between the plantlets. Protect the plants from slugs and snails. Water sufficiently in case of drought.
Sow outdoors from April onwards, when severe frost is no longer expected. Sow the seeds shallowly and press them gently into the soil. Sow in a previously well-fertilised spot with good drainage. If necessary, cover with a very thin layer of soil. Keep 35 - 40 cm apart. Keep well weeded and moist.
Stem lettuce, like all other lettuces, shoots to seed quickly at higher temperatures. This can be avoided by sowing in a sunny place in spring and in a semi-shaded place in summer. Don't let the plants dry out. Both the leaf and stem of this plant are edible. The leaves can be harvested from 35 - 40 days after germination. The stems about 56 - 70 days after germination. The stem with possibly some leaves attached can be kept in the fridge for about 1 week.
