Growing Vegetable Seeds for Sale

LESLIE R. HAWTHORN.

MEN WHO grow vegetable seeds for sale engage in a specialized and highly competitive farming operation.

They compete to maintain superior strains of most standard varieties and to develop new varieties. Most of the large vegetable seed companies have well-qualified staffs to develop and maintain stock seed, from which is produced seed for the market, mostly by farmers who have contracts with the companies.

The producers of vegetable seeds must know the cultural requirements of the vegetables they are growing throughout the life of the plants, not just until they have reached an edible stage. As a food crop, a biennial such as carrot or onion, for example, requires but one year of growth, but as a seed crop it requires two. On the choice between leaving a biennial in the ground over winter or storing it in a cellar may depend the yield and quality of the seeds harvested the following year.

The growers must know whether their crops are self- or cross-pollinated and, if the latter, whether insects or wind carry the pollen. On such facts depend the necessary isolation distances between fields.

Harvesting seeds differs with different vegetables, both in the method of cutting or the picking of the crop, as well as in the operating speed of the threshing machine. Seeds of fleshy-fruited vegetables like tomatoes are extracted often with variations of food-processing equipment rather than threshed, as dry seeds are.

This explains in part why the saving of home garden seed is normally not so simple or satisfactory as it might seem; Experienced seedsmen can grow seeds of good type and true to name for less cost than the home producer, who has a small planting and faces hazards of cross-pollination from nearby plantings of which he may be unaware.

VEGETABLE SEEDS are grown in many States, but most seed acreage is in the West, mainly because of the climate.

Dry air and lack of rain during summer and fall, when many seed crops mature, facilitate the harvesting and threshing. In some western irrigated areas, absence of rain throughout most of the growing season favors the production of disease-free seeds a tremendous advantage, particularly with beans and the cabbage family.

The largest variety of vegetable seeds is produced in California, where a wide range of climatic conditions within a relatively short distance enables seedsmen to supervise diverse crops from a central place.

Cabbage and closely related crops and garden beets and spinach thrive best in a cool, marine-type climate, and seed production is concentrated in the Pacific Northwest, particularly around Puget Sound.

Beans, peas, sweet corn, melons, squash, carrots, onions, lettuce, turnips, radish, and other dry-seeded crops are grown in various interior places in the Western States.

Seed acreages of tomatoes and sweet corn are common in the North Central and Eastern States.

Pimiento pepper, eggplant, watermelons, okra, and edible cowpeas are grown for seed in the Southeast and South.

FEWER THAN 200 thousand acres a year are planted for vegetable seeds in the United States. About 85 percent of this acreage is required for three large-seeded crops garden peas, garden beans (including limas), and sweet corn. Thirty-five small-seeded vegetables take the rest fewer than 30 thousand acres in some years.

About 200 million pounds of vegetable seed may be grown some years, and about 1.4 million pounds are imported. Most of this seed is used in the commercial production of vegetables valued at around 1,111 million dollars.

Peas and green beans are grown for seed almost entirely in the West in localities where the atmosphere is dry. Soil moisture, with one notable exception, is mostly supplied by irrigation.

The exception is in the Palouse areas of northern Idaho and eastern Washington, where most of the seed of smooth-seeded garden peas is grown. Since the irrigated sections of southern Idaho have large acreages of beans and peas, Idaho accounts for the greatest production. Plantings are also common in eastern Washington and in California.

Peas and beans, which are self-pollinated legumes, are grown for seed in much the same way.

Peas are hurt by severe frost, but they should be planted as soon as that danger is past, for they produce higher yields of seed in cool weather.

Beans are sown after all danger of frost is over.

Both crops require at least moderate fertility, but in general they are not fertilized when they are grown for seed. Both require a fair amount of irrigation, but peas usually respond more favorably to additional water.

All but the dwarf varieties of peas usually are sown with a grain drill at rates of 200 to 250 pounds to the acre.

Dwarf peas and all varieties of beans are planted in rows 20 to 30 inches apart, depending on the variety and the equipment that has to be used for other crops in the rotation.

Peas are commonly harvested for seed in midsummer. Beans are harvested in late summer and early fall.

Unlike many cross-pollinated plants, plantings of peas and beans need little isolation. Accidental crossing can take place, however. In the production of stock seed, varieties planted side by side commonly are separated by one or two rows of corn or sunflower. Such barriers help to prevent chance crossings and mixtures at harvest time.

Roguing the removal of offtype plants is done in fields of stock seed. That and a program of rigid control of the quality of stock seed largely eliminate the need to rogue the market-seed crops of peas and beans.

Because both crops are naturally self-pollinated, pure lines can be built up from single plants of the right type. It is essential in such a program that true-to-type plants be selected to protect a variety from gradual change.

Peas and beans are harvested when pods are nearly dry. Pea vines in the Palouse are allowed to dry completely. Then they are combined directly on the stump. A harvesting machine cuts the dry plants close to the ground and elevates them immediately to the threshing cylinders. The seeds are collected in suitable containers usually large boxes, each of which holds 3 thousand pounds of seeds. All that is done in one operation.

Peas and beans in irrigated areas are commonly cut and windrowed and then allowed to cure until they are dry enough to thresh. The seeds are less likely to be injured if they still have a moisture content of 12 to 15 percent.

Threshing machines especially developed for peas and beans have two or more spike-tooth cylinders or rub bars and a pair of rubber rollers. To avoid serious injury, especially to beans, cylinder speeds should not normally exceed 350 revolutions per minute.

Lima beans are handled much like green beans but require a longer growing season. The climate should be warm, but excessively high temperatures or extremely dry air are undesirable, because they may cause excessive blossom drop and therefore low yields.

Large-seeded lima bean seed consequently is grown usually in southern California, where length of season and temperature are favorable and the air usually is somewhat more humid than it is farther inland. Some of the small-seeded lima beans are grown in Idaho.

Cowpeas, or southern peas, have climatic and cultural requirements like those of lima beans. Seed is grown in the Southern States and California. The "black-eyed pea" of commerce is a variety of cowpea.

SWEET CORN, another large-seeded vegetable, is grown in much the same way as field corn.

Corn does best on productive soils with abundant moisture and when the average monthly temperature is about 70 F. A season of at least 120 days is required for seed production. Dry weather during harvest is desirable.

About 80 percent of all sweet corn produced in 1960 was F₁ hybrid. About 80 percent of all hybrid seed is grown in southwestern Idaho. Some, notably open-pollinated varieties, are grown in the Corn Belt, Connecticut, New York, and California.

The wide use of hybrid varieties has revolutionized the growing of sweet corn for seed during the past several decades. The F₁ hybrid is a cross between two inbred lines. A hybrid must be superior to open-pollinated varieties in one or more characteristics, such as yield, uniformity, and quality, to warrant release as a variety.

The seed breeder today has to know how to develop inbreds and to test their combining ability with perhaps hundreds of others. He also must know how to maintain the satisfactory inbreds over the years and how to produce profitably the market seeds from them.

When a gardener uses seed of hybrid sweet corn, he has to buy new hybrid seed each year if he expects to maintain the yield and quality of the ears he is accustomed to producing. As seed saved from a hybrid crop does Dot reproduce another crop of the same high yield and quality as the seed from which it was grown, a grower can hardly afford to use such seed. The seed trade therefore requires a large amount of hybrid seed each year. That demand has led to the highly specialized business of growing such seed.

Methods and times of planting, cultivation, and weed control with sweet corn are practically identical with those used in the production of seed of field corn, whether open pollinated or hybrid. Similar distances of isolation need to be observed. Methods of harvesting and curing sweet corn seed and the use of special drying plants also resemble the practices followed in producing field corn seed.

Seed of popcorn is produced in much the same way as that of sweet corn.

FLESHY-FRUITED vegetables present a special problem because at harvest the seed is wet, rather than dry. These vegetables include several related crops tomatoes, peppers, and eggplants, and some unrelated vine crops cucumbers, melons, squashes, and pumpkins.