CRESS, in botany. “Garden Cress” (Lepidium sativum) is an annual plant (nat. ord. Cruciferae), known as a cultivated plant at the present day in Europe, North Africa, western Asia and India, but its origin is obscure. Alphonse de Candolle (L’Origine des plantes cultivées) says its cultivation must date from ancient times and be widely diffused, for very different names for it exist in the Arab, Persian, Albanian, Hindustani and Bengali tongues. He considered the plant to be of Persian origin, whence it may have spread after the Sanskrit epoch (there is no Sanskrit name for it) into the gardens of India, Syria, Greece and North Africa. It is used in salads, the young plants being cut and eaten while still in the seed-leaf, forming, along with plants of the white mustard in the same stage of growth, what is commonly called “small salad.” The seeds should be sown thickly broadcast or in rows in succession every ten or fourteen days, according to the demand. The sowings may be made in the open ground from March till October, the earliest under hand-glasses, and the summer ones in a cool moist situation, where water from trees, shrubs, walls, &c., cannot fall on or near them. The grit thrown up by falling water pierces the tender tissues of the cress, and cannot be thoroughly removed by washing. During winter they must be raised on a slight hotbed, or in shallow boxes or pans placed in any of the glass-houses where there is a temperature of 60° or 65°. Cress is subject to the attack of a fungus (Pythium debaryanum) if kept too close and moist. The pest very quickly infects a whole sowing. There is no cure for it; preventive measures should therefore be taken by keeping the sowings fairly dry and well ventilated. The seed should be sown on new soil, and should not be covered.
The “Golden” or “Australian” cress is a dwarf, yellowish-green, mild-flavoured sort, which is cut and eaten when a little more advanced in growth but while still young and tender. It should be sown at intervals of a month from March onwards, the autumn sowing, for winter and spring use, being made in a sheltered situation.
The “curled” or “Normandy” cress is a very hardy sort, of good flavour. In this, which is allowed to grow like parsley, the leaves are picked for use while young; and, being finely cut and curled, they are well adapted for garnishing. It should be sown thinly, in drills, in good soil in the open borders, in March, April and May, and for winter and spring use at the foot of a south wall early in September, and about the middle of October.
Water-cress.—“Water-cress” (Nasturtium officinale) is a member of the same natural order, and a native of Great Britain. Although now so largely used, it does not appear to have been cultivated in England prior to the 19th century, though in Germany, especially near Erfurt, it had been grown long previously. Its flavour is due to an essential oil containing sulphur. Water-cress is largely cultivated in shallow ditches, prepared in wet, low-lying meadows, means being provided for flooding the ditches at will. Where the amount of water available is limited, the ditches are arranged at successively higher levels, so as to allow of the volume admitted to the upper ditch being passed successively to the others. The ditches are usually puddled with clay, which is covered to the depth of 9 to 12 in. with well-manured soil.
A stock of plants may be raised in two ways—by cuttings, and by seeds. If a stock is to be raised from cuttings, the desired quantity of young shoots is gathered—those sold in bunches for salad serve the purpose well—and reduced where necessary to about 3 in. in length, the basal and frequently rooted portion being rejected. They are dibbled thickly into one of the ditches, and only enough water admitted to just cover the soil. If the start is made in late spring, the cuttings will be rooted in a week. They are allowed to remain for another week or two, and are then taken up and dropped about 9 in. apart into the other ditches, which have been slightly flooded to receive them. There is no need to plant them—the young roots will very soon be securely anchored. The volume of water is increased as the plants grow. If raised from seed, the seed-bed is prepared as for cuttings, and seed sown either in drills or broadcast. No flooding is done until the seedlings are up. Water is then admitted, the level being raised as the plants grow. When 5 or 6 in. high, they are taken up and dropped into their permanent quarters precisely like those raised from cuttings.
Cultivated as above described, the plants afford frequent cuttings of large clean cress of excellent flavour for market purposes. Sooner or later growth will become less vigorous and flowering shoots will be produced. This will be accompanied by a pronounced deterioration of the remaining vegetative shoots. These signs will be interpreted by the grower to mean that his plants, as a market crop, are worn out. He will therefore take steps to repeat the routine of culture above described. In the winter the ditches are flooded to protect the cress from frost.
The best-flavoured water-cress is produced in the pure water of running streams over chalk or gravel soil. Should the water be contaminated by sewage or other undesirable matter, the plants not only absorb some of the impurities but also serve to anchor much of the solid particles washed as scum among them. This is extremely difficult to dislodge by washing, and renders the cress a source of danger as food.
Water-cress for domestic use may be raised as a kitchen-garden crop if frequently watered overhead. Beds to afford cress during the summer should be made in broad trenches on a border facing north. It may also be raised in pots or pans stood in saucers of water and frequently watered overhead.
In recent years in America attention has been paid to the injury done to water-cress beds by the “water-cress sow-bug” (Mancasellus brachyurus), and the “water-cress leaf-beetle” (Phaedon aeruginosa). Another species of Phaedon is known in England as “blue beetle” or “mustard beetle,” and is a pest also of mustard, cabbage and kohlrabi (see F. H. Chittenden, in Bulletin 66, part ii. of Bureau of Entomology, United States Department of Agriculture, 1907).
The name “nasturtium” is applied in gardens, but incorrectly, to species of Tropaeolum.