This section is from the book "Vegetable Gardening", by Ralph L. Watts. Also available from Amazon: Vegetable Gardening.
This is an annual plant popular in Europe. It finds limited sale in this country. The leaves have a mild flavor and are valued for salad purposes, for greens and seasoning, and the curly varieties for garnishing. As the plants are sensitive to heat, they are grown as a fall or spring crop. They are hardy and may be wintered in the milder sections by protecting in cold frames, or with mulches where the winters are not too severe. Although the plants attain a height of nearly 2 feet, the young leaves are tender and delicious. Two crops may be gathered from the same plants.
The soil should be fertile and contain a bountiful supply of nitrogen. Dressings of nitrate of soda may be made to advantage. For the spring crop, sow in the open as soon as the ground can be prepared, or in the fall as for spinach. For the fall crop, sow late in the summer. The seed should be sown thinly in shallow drills. The rows need not be more than 12 inches apart, the plants thinned to 6 inches. Irrigation is a great advantage in growing this crop.
The piquant leaves of cress are used in salads and for garnishing. Three common forms are in cultivation. They belong to different genera, but all are members of the Cruciferae or mustard family.
Water Cress (Nasturtium Officinale) is a hardy, perennial, aquatic plant popular on all our city markets. The leaves of the prostrate plants are small and roundish. Water cress thrives best in shallow, running water which should be pure and clean. It may also be grown in moist or wet, shady places, but springs and brooks are preferable. With irrigation it is grown to perfection in all soils, although as a commercial enterprise, success is much more certain with favorable natural conditions. It is readily propagated by scattering the small seeds along brooks or about springs or by planting short pieces of the stems in wet soil. When planted in wet, shady spots or under irrigating lines the plants should be set 5 to 8 inches apart each way. They may be easily started under glass early in the spring and transplanted into flats 1 1/2 inches apart and watered frequently.
Garden Or Pepper Cress (Lcpidium Sativum), a popular European salad plant, is grown to a limited extent in the United States. It is an annual and one of the best early salad plants, easily grown in any good garden loam. Moist soils should preferably be very fertile, to encourage a rapid growth and the production of crisp, tender leaves. With favorable cultural conditions the leaves will be large enough to use in four weeks from sowing. Sow thickly in shallow drills about a foot apart. Conserve the moisture by frequent tillage and water artificially, if possible. Gather the leaves when wanted and allow another crop to develop. Garden cress is a spring and fall crop and does not thrive in midsummer.
Upland Cress (Barbarea Vulgaris And B. Proecox) is the least important of the three forms. It is native to a large part of the United States, but is not cultivated to any great extent. It is perfectly hardy and does best as a fall or winter crop. The seed remains in the ground all winter and germinates in the spring. Cultural directions given for garden cress apply equally well to upland cress.
 
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