Celery and celeriac need an extremely rich moist soil with a pH of 6.0 to 7.0. Most home gardeners who grow celery buy 4 to 6-inch-tall seedlings; they can be planted when night temperatures are no longer likely to fall below 40 (lower temperatures make the plants send up inedible flower stalks instead of edible leafy stalks).

A good variety is Michihli. A loose- leaved type, B. chinensis, grows 12 to 18 inches tall and has edible greenish white stalks; a good variety is Crispy Choy. A 10-foot row yields about 12 heads over three weeks.

Chinese cabbage does best in soil with a pH of 6.0 to 7.5. The soil requires special preparation: dig a 2-inch layer of compost or a 4-inch layer of well-rotted cow manure into a strip 12′ to 18 inches wide and 8 inches deep, then add 1 pound of 10-10-10 fertilizer per 10 feet of row.

Swiss chard grows best in soil with a pH of 6.0 to 7.5. In most of the U.S. and southern Canada, where winter frost is expected, sow seeds two to three weeks before the last frost is due; in regions where winter temperatures rarely fall below 25, sow seeds in fall for harvesting most of the following year. Sow the seeds 1 inch deep and about 4 inches apart in rows 18 to 24 inches apart.

If you wish to take the trouble to blanch celery, cover the stalks-but not the leaves at the tips of the stalks-in late fall with ordinary soil; or else lay 12-inch boards or sheets of plastic against each side of the plants, holding the shields in place with soil. Do not pile soil against the stalks in warm weather because it may cause the plants to rot. To harvest celery, pull up the plants and cut off the roots just below the base of each stalk.

The plants are ready to be picked approximately two months after seeds are sown, when outer leaves become 6 to 10 inches tall. Cut off the leaves near the base of the plant with a sharp knife; the undisturbed inner leaves will continue to grow and will be ready for picking a few days later. Pick off and discard any old or tough leaves; if they remain on the plant, they will prevent the plant from producing fresh foliage. Pick off all flower stalks the second year to ensure a second crop.