Miscellany, Including Celeriac, Horseradish, Artichoke, Peanuts, Vegetable Soybeans

by Homer N. Metcalf and Milo Burnham.

Homer N. Metcalf is Professor of Horticulture, Montana State University, Bozeman. Milo Burnham is Extension Horticulturist, Mississippi State University, Mississippi State.

Plants discussed in this chapter will provide both experienced and beginning gardeners with an introduction to the fascination of growing uncommon vegetables. Once culture of the easier vegetables has been mastered, the natural tendency of gardeners is to extend their experience. Unusual vegetables which may require special production techniques provide a stimulating challenge.

Information is provided for celeriac, chayote, dasheen, globe antichoke, horseradish, husk tomato, martynia, mushrooms, peanuts, sunchoke, vegetable soybeans, and watercress. Of these, celeriac, chayote, husk tomato, martynia, peanuts and sunchoke occur naturally in some parts of the Western Hemisphere. The others are from Eurasia or Oceania. Irrespective of their ultimate origins, they all are fascinating to grow and delightful to eat.

Because these vegetables are, for the most part, of no or minor commercial importance in the United States, comparatively little research has been devoted to them. Hence, the cultural practices suggested are often less exact than would be the case for major vegetables. Experience will certainly improve the home gardener's skill in growing them, but lack of experience should not deter him from giving them a whirl.

Since soil conditions vary so widely over the country, no specific recommendations for fertilizer usage are included, other than for fresh manure. In general, most efficient utilization of applied fertilizers will be obtained where 5% to 6% soil organic matter can be maintained. Home gardeners are urged to follow locally applicable fertilizer recommendations based on the results of soil tests that can be obtained through their county Extension office or commercial soil testing laboratories.

Resistant varieties are the first line of defense against diseases, insects, nematodes and other troubles. Where resistant varieties are not available, the home gardener should consult his county Extension office for information about recommended pesticides.

Celeriac

Celeriac (Apium graveolens L. var. rapaceum DC.) is a botanical variety of celery, differing from that vegetable in producing at the base of the plant a large, turnip-like swelling that may be as much as 4 inches in diameter. This rather bulbous base is the commonly eaten part of the plant.

Celeriac like celery, carrots, parsley, parsnips and dill is a member of the Parsley Family (Umbelliferae or Apiaceae). The plant is a biennial, growing to about 36 inches in height, but in gardens it is treated as an annual. It is naturally distributed in marsh areas in the temperate zones of South America, South Africa, New Zealand and Eurasia.

Celeriac "bulbs" may be boiled like potatoes, and put to all the uses made of boiled potatoes. Boiling time for celeriac will be somewhat longer than for potatoes. Celeriac may also be Grated raw as a salad topping. An intriguing use is serving sliced, boiled celeriac with French dressing as an hors d'oeuvre. Celeriac has the odor typical of celery due to the presence of a volatile oil. Celeriac is comparatively low in nutrients.

several varieties of celeriac are grown in Europe, Giant Prague has been the only one readily available in the United States. A newer variety is Alabaster.

The culture of celeriac is very similar to that for its close relative, celery. It is a long-season vegetable, requiring nearly 6 months from seeding to harvest, and growing best where the monthly growing season mean temperature is 60 to 65 F (approximately 15.5 to 18.5 C). It is unlikely to be grown successfully in areas or at seasons where monthly mean growing season temperatures exceed 70 to 75 F or are lower than 45 . Since celeriac plants grow rather slowly, a freeze-free growing season of at least 110 days is desirable.

The home gardener has two options for production of celeriac. He may either purchase seedlings from a vegetable plant grower or raise them himself. The use of purchased transplants is suggested for short growing season areas, while gardeners living in milder climates may take either route. Gardeners raising their own transplants should be aware that celeriac must have 60 to 65 F night temperatures throughout the seedling and early transplant stages if premature seed-stalk development is to be avoided.

When home-grown transplants are to be used, the gardener will soon discover that celeriac seeds are quite small (approximately 70,000 per ounce). They will remain viable for 4 to 5 years under cool, dry storage conditions. Thus, one need purchase Only a small quantity of seed at a time.

Seeds may be sown in flats or individual peat pots. If sown in flats, a seeding rate of 8 seeds per inch of row is suggested. If seeded in individual peat pots, about 10 seeds per Pot should be sown, with the extra seedlings later thinned to one per pot. Celeriac seeds characteristically have germination percentages of 50% to 70%, and germinate best at a 70 F minimum temperature. If maintained at this temperature, germination should be complete in about 10 days. Following germination, night temperatures of 60 to 65 are desirable, with daytime temperatures 10 warmer. If seeded directly in the garden, germination and emergence will be materially slower.

Flat-grown seedlings should be transplanted to individual pots as soon as the first true leaves develop. Weekly feedings with a complete liquid fertilizer will promote sturdy growth.

Plants will be ready to transplant to the garden 8 to 12 weeks after seed-sowing, or when they are 3 to 4 inches tall.

Celeriac needs a deep, fertile, well-manured soil which retains moisture well throughout the growing season. Fresh manure, if available, should be applied at the rate of 55 to 92 pounds per hundred square feet. The quantities of lime and commercial fertilizers used should be governed by the results of soil tests. Since celeriac is a gross feeder, two or more side-dressings with readily soluble nitrogenous fertilizers during the growing season are suggested. Regular irrigation will prove beneficial.

As a rule, wait until 5 days after the average last spring freeze-date to set out the transplants, at which time maples may be coming into leaf in many areas. In the garden, the transplants may be spaced, or seedlings thinned, to stand 6 to 7 inches apart in rows 24 to 36 inches apart. An alternative is to check-row the plants at 15 to 18 inches apart in rows 18 inches apart, a system more likely to produce exhibition-quality plants.

Higher quality celeriac will be produced if sideshoots and withered leaves are removed as they appear. Mulching the rows with lawngrass clippings is sometimes practiced, especially where no manure has been used and irrigation is not available. A further quality-producing practice is to draw soil up around the plants to the level of the leaves about two weeks before harvest. This will yield a whiter product, and is called "blanching".

Celeriac will generally be ready to harvest in October, or when the "bulbs" have attained diameters of 2 to 2.5 inches. The plants may be pulled or dug, depending on soil conditions. Tops are trimmed off and any branching basal roots removed. Yields of 200 bulbs per 100 feet of row are a reasonable expectation. The trimmed "bulbs" can be stored in moist sand in a cool root cellar, in a vegetable pit, or in colored plastic sacks in a refrigerator. Properly stored, they will keep about 6 months.

Celeriac troubles will be similar to those afflicting celery.