This section is from the book "The Potato: A Compilation of Information from Every Available Source", by Eugene H. Grubb, W. S. Guilford. Also available from Amazon: The Potato: A Compilation Of Information From Every Available Source.
Within recent years there has been a marked increase in the use of second-crop potatoes for seed throughout the Southern potato-growing sections. This crop is frequently grown on the same land from which the first crop of potatoes was harvested. In most instances, however, it follows beans or cucumbers, as the seed for this second potato crop is not usually planted until July or August. The seed for this crop is, as a rule, saved from the early crop, the small tubers being stored in a well-ventilated shed, where they are protected from the direct action of the sun and from storms until about ten days or two weeks before the time of planting, when they are spread thinly upon the ground and lightly covered with straw or litter to partially protect them from the sun. Under these conditions the tubers quickly 'green' and all those suitable for seed will develop sprouts. As soon as the sprouts are visible, and before they are large enough to be rubbed off in handling, the potatoes are ready to plant. The product of this planting gives a crop of partially matured tubers which are held over winter for spring planting. This practice gives excellent results in many localities and is found to be more economical than the purchase of Northern-grown seed. To what extent it is safe to follow this practice without renewing the seed from the North by the use of fully matured tubers has not been determined.
A novel practice for securing quick growth from second-crop seed has been developed by a successful potato grower in Texas. Mr. Morrell has developed an idea which is closely akin to the practices of the potato growers of the Channel Islands. The method consists in storing the tubers of the second crop in a tight building, which by the use of artificial heat can be kept frostproof. At harvest time the tubers are placed in slatted crates and the temperature of the storage house held as low as practicable without freezing until four to six weeks before planting time, when the temperature is raised to 68 degrees or 70 degrees F. This temperature is maintained until the eyes of the potatoes show activity. The sprouts should not be allowed to develop to any considerable length before planting the tubers, on account of the danger of breaking them in the necessary handling at planting time. If the sprouts are one eighth of an inch or less in length there should be little loss from handling. If the house can be well lighted at the time the temperature is raised the sprouts which develop will be much stouter than those developed in the dark. This plan provides a congenial temperature for the germination of the tubers and makes it possible to delay planting until outside conditions are generally favorable for the rapid growth of the plants, and to use for seed only those tubers which are actually viable. With good preparation and cultivation this method should give a perfect stand and a decidedly increased yield, together with the early maturity of the crop.
This plan has been used for Northern-grown seed, but it is found that the mature Northern-grown seed responds more quickly to a given heat stimulus and consequently does not require to be placed in a warm room more than ten days to two weeks before planting.
The practice on the Channel Islands accomplishes the same results in a slightly different manner. The tubers are placed one layer deep on germinating trays which are arranged on racks or are provided with corner posts a few inches long so as to admit air and light. The tubers are induced to germinate in the trays, and at planting time only those with well-developed sprouts are used for planting. As the work is all done by hand there is little danger of damage to the seed from breaking off the sprouts. In all sections of the South where hand planting is practised this method of procedure is perfectly practicable, and would entirely obviate losses from poor stands resulting from uncongenial conditions due to cold, damp spring weather, and inferior seed. Planting could be delayed until conditions were favorable and poor seed would be detected before it was planted.
Early potatoes grown as market-garden or truck crops and intended for immediate consumption are, as a rule, harvested as soon as they have reached marketable size, regardless of the maturity of the crop. Because of the immature condition of the tubers it is essential that the crop be handled carefully and quickly. The tender tubers are easily bruised and damaged in appearance; consequently care should be exercised in the conduct of all operations connected with the harvesting of this crop. As a further safeguard to loss from bruising at harvest time or during transit the growers and the trade have determined upon the red-skinned varieties as best adapted to withstand these misfortunes. Scars and bruises show less on red-skinned than on white-skinned sorts.
The varieties in most common use among truckers are known as Irish Cobbler, having a white skin, and Bliss Triumph, a red-skinned sort.
Notwithstanding the fact that red-skinned sorts handle better, the smaller yield usually obtained from such varieties has led all growers except those located at extreme distances from the market to use white-skinned sorts. Red varieties are not employed extensively along the Atlantic coast, although they make up the bulk of the crop grown in the Gulf Coast States.
While the harvesting of early Irish potatoes grown for home consumption is largely carried on by hand, in some localities improved implements, such as potato diggers and potato sorters, are brought into service. The truck farmers along the Atlantic coast, however, adhere largely to the simpler methods of handling the crop, as suggested in figures 9 and 10. This is undoubtedly accounted for by the fact that labor is more abundant and not so well trained in the use of improved machinery as in the more northern and western districts. In digging early potatoes in the Atlantic coast district ordinary one-horse turning plows are used. Laborers follow the plows and gather the potatoes from the soil and throw them, four or six rows together, in piles, after which they are sorted and put into barrels for shipment. In the potato regions of Louisiana and Texas, where early potatoes form a crop of considerable importance, improved machinery is largely depended upon for harvesting.
The packages for early potatoes are determined partly by custom and the demands of the market, but largely by the local timber supply. In regions where timber is plentiful and barrels and crates figure largely in the shipment of other truck crops, potatoes are chiefly shipped in barrels. In other localities burlap sacks are chiefly employed, as is the case in most regions growing late potatoes.
Up to the present time no standard measure, barrel, or bag for the handling of potatoes has been adopted. Recently certain states have passed laws requiring that these packages should come up to a given standard, usually 170 pounds net for a barrel, and that all short-measure packages entering their markets should be so marked. The barrel used by the trucker of the Atlantic coast region during past years holds about 11 pecks and weighs from 155 to 165 pounds net. These barrels cost the grower about 22 cents each, including the burlap cover. The bags used for the handling of the crop grown in the southwestern region cost the grower about 5 cents each in lots of 1,000 or more. These packages are used but once and are not returned to the grower.
The grading of early potatoes is quite as important as the grading of fruits. Large and small tubers should not be mixed in the same barrel. The pickers should be taught to gather the large and merchantable tubers in one basket and the small or seed potatoes in another, and these if placed upon the market should go in separate receptacles and be clearly marked so as to represent the grade. If a mechanical sorter is used this work will be more effectively accomplished than if left to the pickers.
The type of grade usually used is similar to that employed in some sections for grading apples and peaches, although the common type of potato grader is a rotary screen which separates the earth from the tubers and allows the small tubers to fall through the large meshes of the screen before reaching the general outlet which carries away those of merchantable size. The objection to a mechanical grader of this type is that it bruises the immature tubers and renders them somewhat less attractive than when not so handled and probably also shortens the length of time they can be safely held on the market."