Decandolle ("Origin of Cultivated Plants," p. 330) makes the following statement in regard to the origin of the garden pea: "The species seems to have existed in western Asia, perhaps from the south of the Caucasus to Persia, before it was cultivated. The Aryans introduced it into Europe, but it perhaps existed in northern India before the arrival of the eastern Aryans. It no longer exists in a wild state, and when it occurs in fields, half-wild, it is not said to have a modified form so as to approach some other species".
The pea is one of the important vegetables grown in the United States. It is almost invariably planted in home gardens, and truckers regard it as one of their leading vegetables for early and midsummer sales. The crop is also canned to a great extent.
The table in Chapter XXV (Tables) shows that this is one of our most nutritious vegetables. Besides being wholesome, the young tender peas are regarded as a delicacy. Being a legume, the soil is improved by its culture and this advantage is considered by truckers who are alert as to methods of making their lands more fertile.
Varieties of peas may be classified as dwarf, half-dwarf .and tall. The dwarf varieties, because they do not require support, are most largely grown. The tall varieties, for the ground occupied, produce much heavier yields, but must be supported. Varieties are also classified as smooth and wrinkled; there are dwarf and tall varieties of each class. The smooth peas may be planted earlier than the wrinkled, because they do not rot so quickly in the soil and the plants are hardier; but the wrinkled peas are sweeter and superior in quality.
A third class, known as edible-podded or sugar peas, is grown to some extent in this country. The young tender pods are excellent when properly cooked and seasoned. They may also be shelled, and only the peas eaten.
Among the many varieties of peas the following are the most important:
Alaska is the most extensively grown for canning. The vines are 20 to 30 inches in height. The peas mature practically at one time. Uniformity in time of maturing is exceedingly important when the peas are grown for the canneries. This variety is inferior to some other early varieties in flavor.
All of the seedsmen offer strains of extra early peas, often of the Alaska type. Some are probably superior to the well-known variety bearing this name.
Gradus is a very early, largely planted variety. The large pods contain large peas which mature only a few days later than the smaller, smooth peas. Vines grow about 3 feet high.
Thomas Laxton is a close rival to Gradus, ripening a few days later. Pods and peas are large and of fine quality. Vines grow to the height of about 3 feet.
Nott's Excelsior is an improvement on the old American Wonder, the pods being larger and the plants much more prolific. Average height is about 14 inches. It is a popular early variety of high quality.
Improved Stratagem grows to the height of about 2 feet and does not need support. Pods are large and well filled with peas of the best quality.
Telegraph, which produces very large pods containing 10 to 12 peas, is a popular variety.
Other varieties valued for late use are Fillbasket, Abundance, Champion of England, Duke of Albany, Laxton Evolution, Boston Unrivaled, Senator, Pride of the Market, Telephone, Lincoln and Long Island Mammoth.
Giant Sugar, Dwarf Gray Sugar And Mammoth Melting Sugar are the edible-podded varieties.
The pea is sensitive to heat. It thrives best in cool weather. For these reasons the large commercial plantings are made very early in the spring. The North naturally provides the best conditions, although excellent results are obtained throughout the South when advantage is taken of the cooler months. It is grown largely for northern shipments in some of the trucking districts of the South. There must be an ample rainfall to insure a full crop. In hot weather the growth is weak and mildew is liable to appear. Unless the growth is very tender, the plants will stand hard freezing, although they are sometimes injured when freezes occur after several days of good growing weather.
A cool, moist but well-drained soil is essential to the largest yields. The sandy loams are preferred, although good results can be obtained on any loose, friable and well-prepared soil. The heavier soils are greatly improved for peas by the addition of humus in some form. Clay and silt loams are used advantageously for the late crop.
The pea does best in soils abounding in vegetable matter, but not containing excessive amounts of nitrogen. Land highly manured the preceding year furnishes ideal conditions for peas. Fresh stable manures should never be employed immediately before planting, but rotten manure may be used freely. When clover sods, crimson clover, cowpeas and soy beans are available to plow down, there is no need of stable manures. The bulk of the crop is grown by the use of commercial fertilizers. Although it is a legume, the early plantings begin growing long before nitrification is active, and some quickly available nitrogen is therefore essential for the early plantings. A small percentage of nitrogen is very generally regarded as profitable for plantings at all seasons, but there must be no lack of the mineral elements. Five hundred pounds of fertilizer containing 2 or 3 per cent of nitrogen and 8 to 10 per cent each of phosphoric acid and potash should meet the requirements of this crop. When grown for the cannery it is desirable to haul the vines back to the farm for their fertilizing value.
For the earliest crop the seed should be planted in March or as soon as the ground can be prepared. Wrinkled varieties are often planted as early as the smooth sorts, but it is safer to plant them a trifle later. For the fall crop in the North, the dwarf varieties should be planted early in August.
The depth of planting must be determined by the character of the soil and the season of the year. For the first planting, shallow covering, probably with only an inch of soil, is an advantage, although 2 inches would not be too much in light soil. As the season advances, planting should be deeper, so that the roots will be where the soil is cooler and more moist. When planted 5 or 6 inches deep, the covering should be shallow at first, and the furrows gradually filled in after the plants are up.
Planting distances depend upon the height of the vines, whether the vines are to be supported or not, and the purpose of the crop. When grown for the cannery they are often sown with a grain drill, and the crop harvested with a mowing machine and a hay rake. They are also sown broadcast sometimes, and the seed harrowed in. When sown in drills the space between rows varies from 18 inches to 3 feet. It generally pays to use plenty of seed, especially with dwarf varieties. (See table in Chapter XXV (Tables)).
When grown for commercial purposes the low varieties are generally planted and no support is provided. In smaller plantations, brush is often used. A neat, convenient method is to plant in double rows 6 to 8 inches apart, and stretch poultry netting of the proper height between the rows. Another very good plan is to drill in single (or double) rows, drive strong end stakes on both sides of the rows, and plastering lath at intervals of 8 or 10 feet. The lath are driven opposite each other, brought together at the top and tied. Strands of common wrapping cotton are then stretched on both sides, from stake to stake as close together as may be necessary to give the proper support.
Care must be taken to harvest the crop before the peas have hardened. When sold to canneries, peas are shelled by machinery, and the shelled peas passed through screens of various-sized meshes, the smallest peas bringing the highest prices. Profits are sacrificed if the crop is cut too soon. The peas are sometimes shelled before marketing, although they are generally sold in the pod in half-bushel and bushel baskets or hampers. If the peas are plunged in cold water before sending to local markets they will retain their plumpness and reach the market in better condition than if shipped direct from the field. With the early varieties, two or three pickings will remove practically the entire crop; the vines should then be plowed down and some other crop started. Gross receipts vary from $40 to $100 an acre, and sometimes even more. The cost of picking is the heaviest expense.
The Pea Aphis (Nectarophora destructor) is one of the most serious pests. It attacks the terminals of the young vines and soon destroys their vitality. Often large areas become infested and entire crops destroyed when conditions are favorable for breeding. Early planting or very late planting for canneries may be the means of escaping serious attacks. Kerosene emulsion is the standard treatment, which should be applied on both sides of the leaves as soon as the insects appear. Tobacco dust sprinkled on the young plants as soon as they are up is also valuable.
The Pea Weevil (Bruchus pisorum) produces heavy losses sometimes. To avoid trouble from this pest, seed peas should be treated with bisulphide of carbon at the rate of I or 2 ounces to 100 pounds of seed.