Celtuce, 'Wo Sun'

Celtuce is a non-hearting relative of the lettuce, originating from southern China it was known as ‘Ou sen’.
It was introduced into the western world in the 1890’s and was originally known as Asparagus Lettuce.
Today, WōSŭn it is more often transliterated as Wo Sun, Wo-ju or Wo-chu. it is also known as stem lettuce, celery lettuce or Chinese lettuce.

Celtuce is named after its unique combination of characteristics, the celery-like stalks and the lettuce-like leaves. It resembles a Romaine lettuce sat on top of a long, thick stalk.
The inner stem has the same kind of juicy crunch that makes celery appealing. Although some find a celery-like taste when raw the flavour is milder and more delicate. It is more often compared to asparagus or even cucumber when cooked. Since it does have such a mild taste Celtuce is the perfect foundation of many full flavoured dishes.

In China, the plant is valued for the thick central stalk that is very crispy and tender, while the young leaves are used as lettuce for salads and stir-fry. When grown to maturity the Celtuce stems become quite large and can weigh up to as much as 1kg. The stalks are stir-fried with meat, poultry or fish; they can be used in soups or pickled.
The leaves can be used like spinach. They may be eaten in salads at a young tender stage and as the plant grows they can be harvested straight from the stem and lightly cooked.

Celtuce is a cool weather crop with spring and autumn sowing recommended for best results. Very easy to grow. It will grow to maturity in 90 days. Simply space 20 to 30cm (8 to 12in) in the row, and treat like regular lettuce.

Prepare the site:
A rich soil is excellent for any member of the lettuce family, but the crop will also do well in average garden soil. The best crops are grown in soil that is deeply enriched with well-rotted manure and is well-fertilized before planting, especially with high nitrogen--leaf-stimulating--fertilisers such as 10-8-4, cottonseed meal, or blood meal. Lettuce doesn't do well in very acidic soils, and some say the pH shouldn't be lower than 6.5.

Timing:
Lettuce is about 95 percent water. It develops rapidly if the growing season is cool and moist. It can grow from seed to salad in about 1 month in many regions, and only a little longer in others. Lettuce is a cool-season vegetable, with an ideal temperature of 10 to 16°C (50 to 60°F); it does poorly in hot weather, and is tolerant to some frost and light freezes. Cos is more heat tolerant than most. The secret of having salad leaves in spring is to sow them in late summer and the New Year, the first to overwinter and the second to provide an in-between harvest before the spring sowings become big enough to pick.

Sowing:
Sow indoors under protection: Sept to Mar or sow directly outdoors: March to Aug
Lettuce germinate at surprisingly low temperatures The perfect temperature for germination is 4 to 16°C (40 to 60°F) rates decline above 20°C (68°F) and seeds will not germinate once temperatures rise over 27°C (80°F). The perfect temperature for growth is 16 to 18°C (60 to 65°F)
Sow at a seed depth of 6 to 12mm (¼ to ½in) Seed will germinate in 7 to 14 days.

Sow seeds in short rows about 30cm (12in) apart. To do this, make a shallow trench with a cane about 1.5cm (½in) deep. Space the rows 20cm (8in) apart.
If you are sowing directly into the soil, (if you do not have a problem with slugs!), water the drill before sowing to cool the soil down. A shaded part of the garden is ideal. If birds are a problem in your garden, spread netting to prevent them eating the seed.
Tip a small amount of seed into your hand, take a pinch and spread thinly along the trench. Cover with soil, label and water. When the seedlings are about 2cm (1in) tall, thin them out to give them space to grow, 15-20cm (6-8in). Replant or eat the seedlings. Make successional sowings at 14 day intervals.

Cultivation:
In summer, a mulch of grass clippings, salt hay, clean straw, or the like, will keep the weeds out and the growing soil moist and cool. The plants need almost constantly moist ground, watering is essential if rainfall is scant. This is particularly important when the lettuces are one or two weeks away from harvesting, as dry soil now will cause the plants to put their energy into producing flowers.
The key to tender and tasty lettuce is rapid growth, however lettuce has a relatively shallow and compact root system that doesn't absorb nutrients and moisture from the soil very efficiently, which can slow the growth. To encourage fast growth, add plenty of finished compost before planting and again as a side-dressing a week or so after seedlings appear or transplants are planted. Give supplemental feedings of compost tea every few weeks until harvest.

Pests:
Aphids – Wash off minor infestations before the plants are eaten. If there is a heavy population grow nasturtiums near the lettuce, or use an organic solution.

Harvesting:
90 days to maturity. Harvest all lettuce in early morning for the maximum carotene and best taste and refrigerate immediately. Harvest as soon as they are big enough for the salad bowl. The harvest is over when flowers starts to form as the leaves start to get bitter.

Rotation considerations:
Avoid following radicchio, endive, escarole or artichoke.

Good Companions:
All brassicas (except broccoli, but especially radishes), beat, carrot, cucumber, onion family, pole lima bean, strawberry

Bad Companions:
None

Origin:
Todays cultivated lettuces probably originated from the wild lettuce Lactuca serriola, which was used as a medicinal herb. Open loose types of lettuce with distinct Cos-like leaves were used in ancient Egypt, about 4,500 B.C. Lettuce was also popular in the classical Roman and Greek civilizations. It was introduced into China about A.D.600-900, and the stem lettuce evolved there.
Grown for centuries in China, particularly in the western region near Tibet, it was known as ‘Ou sen’. It was introduced into the western world in the 1890’s and was originally known as asparagus lettuce.
Today it is more often transliterated as Wo Sun, Wo-ju or Wo-chu (or woo chu), it is also known as stem lettuce, celery lettuce or Chinese lettuce.

In 1938 Celtuce seeds were sent from China in by a missionary, the Reverend Carter D. Holton, to W. Atlee Burpee company, the great seedsmen of the United States. Four years later in January 1942 they offered celtuce in their catalogue. Described as a 'novel' vegetable, it was said it received the first seeds from a missionary deep in the interior of China near to the border of Tibet.
It seems that this was a reintroduction, and that seeds had been on sale in America in the 1890s, as asparagus lettuce. Again, a reference to the delicious stalk.

Nomenclature:
A white latex oozes from its leaf base and the thicker ribs of older, larger leaves and is reflected in its Latin name ‘Lactuca’, which means milk.
The species name sativa simply means that it is cultivated and eaten, while the variant name angustana is from the Latin meaning 'narrow' referring to the stem of the plant. .

Culinary Use:
Popular in China from where it originates Celtuce is usually used in stir-fries and soups, eaten fresh or pickled. The leaves can be pulled from the stem as the plant grows and used in salads, or lightly cooked.
When the stem is about 30 to 45cm (12 to 18in) long, cut into the leafy portion of the plant, being sure to peel the outer skin, to remove the portion containing the bitter sap. The soft, translucent green central core is the edible part. It may be eaten fresh, either sliced or diced into a salad. The flavour is somewhat like a cucumber, yet a little different. In China, where it is grown in commercial quantities, the fleshy stem is cut into sections and cooked by broiling or stewing.

Using the Leaves
The tuft of mild-tasting leaves at the tip of the celtuce can be eaten raw, like lettuce, or used as a cooked green. Older leaves are slightly bitter so are best used as a bitter accent in a green salad rather than the main ingredient. More commonly, the leaves are either steamed or stir-fried, much like spinach. The leaves can be used whole or shredded in recipes that call for other greens such as chard, collards or kale.

Preparing the Stem
The stem of the Celtuce is covered with a woody skin, much like a broccoli stem. It must be peeled off with a paring knife or vegetable peeler first, leaving the delicately flavoured stem behind. Start at the bottom, where the skin is thickest. Trim it away with a paring knife or vegetable peeler until the stem underneath has been laid bare. You'll have no difficulty distinguishing visually between the tender inner stem and the woody skin.

Cooking the Stem
The inner stem has the same kind of juicy crunch that makes celery appealing, though they don't taste much alike. Its flavour is milder and more delicate. Although some find a celery-like taste when raw, it's more often compared to asparagus when cooked.
Slice or shred the stem for eating raw in salads, or on buffet vegetable trays. Cut the stem into 2-inch lengths and quarter them for steaming, or use shredded or thinly sliced celtuce stem in your stir-fries. Substitute celtuce stem for celery in soups or classic French preparations such as braised celery.