Forcing
Read about Forcing in the Standard Cyclopedia of Horticulture
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Forcing. The word forcing is variously used. Properly, it should designate the growing of plants outside their usual or normal season. This distinguishes forcing from the ordinary purpose of the glasshouse, which is to imitate the usual season in which plants grow. For example, begonias are not forced: we endeavor to protect them and to give them the season and the conditions under which they grow in the wild. Carnations when flowered in the winter are forced, because we transpose their seasons. Chrysanthemums blooming in-October and November are not forced: they are only protected. Sometimes the word forcing is used in a very special sense, to denote the production of flowers from bulbs or tubers in a very short time under the influence of a very high temperature. Thus, the lily-of-the-valley may be placed in a temperature of 90° or above, and the large buds be forced to throw out their flowers before the plant secures a firm foothold on the soil. A forcing-house is a building in which plants are forced; but the term has come to denote a simple glasshouse in which plants are grown only for sale, in distinction from private conservatories, or more elaborate structures used for the display of plants. See Greenhouse. The forcing industry in America is very large. At first it was confined mostly to cut-flowers (which see), but pot-plants, vegetables and fruits are receiving more and more attention. The staple forced flowers are the rose, carnation, violet, lily-of-the-valley, and various bulbs. These are treated under their respective names. Of vegetables, the most important forcing species is lettuce. This is followed by tomato, cucumber and radish. Other vegetables are of very minor importance as forcing products. The growing of fruits under glass is receiving increasing attention in this country. Very little of this fruit-raising is really forcing, however, since the glass inclosure is used chiefly to protect the plants and to enable better care to be given: the fruit does not ripen much ahead of its normal season. Of this category are glasshouse grapes. Strawberries are really forced, however, the whole period of vegetation and bloom being greatly forwarded. Much attention is now given by florists to the forcing of hardy plants: and this is one of the most delightful of horticultural operations for the amateur. Many of our native plants can be forced with the greatest satisfaction, but the business is usually confined to imported stock of florists' plants. The forcing-house should be of the simplest construction. The plan should secure the greatest amount of light, economy of space and of heating, and directness and simplicity in every operation. The simple sash-bar frame, without rafters (Fig. 1541), is most satisfactory when properly constructed. The side walls should be low and the roof comparatively flat. Often there is no glass on the side walls. Under most conditions, the house should run north and south, particularly if even in span (Fig. 1542), but the lay of the land and the location of existing features usually determine the direction. If the house runs east and west, or if it stands on sloping land (Fig. 1543), an uneven or broken span is usually advisable. The widely different opinions respecting the merits and demerits of the different spans are proof that each is good under certain circumstances. It is the prevailing opinion that, in broken spans, the long roof should be to the south; yet formerly some glasshouses had the short span—which is then very steep—facing the south (Fig. 1546). In America, all forcing-houses are heated by means of small wrought-iron pipes, which fit together with threads. The old-time cast-iron flues may be employed for conservatories, but they are too bungling for forcing- houses. They do not admit of sufficient modification in layout to adapt them to the long and often crooked runs of forcing-house establishments. The wrought- iron pipes are heated either by steam or water. Each system has its advocates, which means that each has its merits. Steam is less costly to install, since less pipe is required. It also admits of greater variation in the layout. Crooks and obstacles are more easily overcome. In a large establishment, the place may be heated up sooner. Hot water gives a milder heat because the pipes are less hot. Of itself, it is less liable t« fluctuations. Theoretically, it is less expensive in fuel; but in practice, the cost of running is found to depend more on the character of the particular system and the operations of the fireman than on the medium itself. When properly installed, steam is as uniform in action as water, and it is adapted to larger areas and to higher temperatures (p. 1403). Very good shape for a forcing-house in the proportion of breadth to length is probably as 1 is to 4 or 5. The best houses are rarely less than 18 or 20 feet wide, and rarely more than 30 to 35 feet. From 400 to 800 feet is considered to be a good range of profitable length. Houses of greater length are constructed, but they must be considered as special cases. Parallel houses are often "nested" with good results,—the adjoining houses resting on a common wall. When the various houses are to be used for one kind of crop, the partitions between them may be omitted; a very large space may then be covered with practically one house without . the necessity of rearing a high roof. The size of house tends constantly to increase. The accompanying illustrations (Figs. 1541-1548) show old and recent styles of American forcing-houses. For further discussion of glasshouses, see Greenhouse. The forcing of vegetables. The title "vegetable-forcing" may be applied to any method of growing vegetables which will cause them to mature or to become suitable for use in a shorter time or at a different season than when grown under normal conditions. This includes the growing of vegetables in coldframes, hotbeds and vegetable forcing- houses. Coldframes. Coldframes are box-like structures about 6 feet in width and of any desired length. They usually are built to run east and west and with the north side a foot or so higher than the south side. These frames are sometimes covered with muslin but usually with sash in which glass is fastened. The frames serve not only as a protection against cold winds and frost but as a means of catching the sun's rays which may pass through them. In this way, a higher temperature can be maintained in these frames than that which prevails in the open at the same time. Coldframes are used for the purpose of starting crops early and thus growing them to maturity earlier than they can be grown outside, and also for the growing of plants for the field- crops. Hotbeds. Hotbeds are similar in construction to coldframes. The chief difference is that in the hotbeds fresh horse- manure is used to supply heat. The manure is firmly packed to a considerable depth, in a pit dug for that purpose inside the frame. Rich garden soil is placed over the manure to a depth of about 6 inches. As the manure ferments, the heat thus formed penetrates the soil above, thus furnishing a satisfactory medium for plant-growth. Hotbeds are in common use in connection with private gardens in all sections of the country except where freezing weather does not occur. They are used extensively in a commercial way in and near most of the large cities in northern latitudes, and especially such cities as Philadelphia, Cincinnati and St. Louis. Crops are grown to maturity more commonly in hotbeds than in coldframes. Vegetable forcing-houses. Figs. 1547, 1548. The growing of vegetables in vegetable forcing- houses has become a very popular and profitable line of work in many sections of the country. The area of glass devoted to vegetables has increased with great rapidity during the last few years. The first section of the country to become noted as a forcing center was Boston, Massachusetts. Soon afterward Grand Rapids, Michigan, became an important vegetable-forcing locality. The Grand Rapids growers did not copy after the Boston growers, however, as their soil,houses, varieties and methods in general differed very materially from those used by the Boston growers. Vegetable-forcing, as conducted by the Boston growers, was rapidly extended to other places in the eastern part of the United States. The development of the industry was even more rapid and became more extensive in Michigan and nearby states. Grand Rapids methods, with modifications, were followed very largely in this section of the country. The greatest development has occurred in northern Ohio, especially at Ash tabula, Toledo and Cleveland. However, nearly every city of much size, in the northern part of the United States, has in or near it one or more vegetable forcing-houses. The amount of money invested in these houses is enormous. A single acre under glass represents an expenditure of $15,000 to $25,000, depending on the kind of material used and the cost of the material at the time the building was done. Success in the growing of vegetables under glass does not depend upon climate. Vegetables can be grown in greenhouses in any state of the Union and in any country on the earth in which vegetation flourishes. However, vegetables can be grown under glass more cheaply in moderately warm climates than in cold regions, and more easily where much sunshine occurs than where cloudy weather is prevalent. As the gardener makes his own soil for the forcing- house, to a considerable extent, the character of the native soil is not so important as is the case with most field-grown crops. However, a sandy soil can be prepared for the forcing-house more easily than can a heavy clay soil. A good vegetable-forcing should contain an abundance of plant-food, should have a good water-holding capacity, be capable of easy working and be as free as possible from weed seeds and disease germs. A very important factor in determining the financial return from vegetable-forcing is nearness to market. Other things being equal, the closer the grower can get to the consumer the greater the profit. Cheapness of fuel for heating purposes is also very important. If coal is to be used, the hauling should be considered when estimating the cost. No one thing has more to do with the success or failure in vegetable-forcing than the man who runs the business. To be a success he must enjoy the work. He should have an understanding of the requirements of the crops to be grown and ability to apply himself diligently to his work. Careful attention to details is of greater importance in connection with vegetable- forcing than with any other line of vegetable-growing. Besides being a good grower, he should be a good salesman. The forcing of lettuce. Fig. 1548. Head lettuce.—As this crop has special treatment elsewhere, it will need but brief mention here. The Boston growers grew head lettuce from the beginning. They were successful in the growing of it and the markets in which they sold demanded head lettuce. The soil used by the Boston growers is of a very loose texture, being well filled with organic matter. In working over the soil in the houses it is spaded to a depth of 1 ½ to 2 feet. Large quantities of manure are added at frequent intervals. Some growers practise steam sterilization. Heavy watering is done before the plants are set in the beds. The water-holding capacity of the soil is so great that usually no further watering is necessary until the following crop is to be put in. The lettuce is allowed to develop until the heads become large and solid, when they are cut, trimmed, washed and carefully packed in boxes, three dozen heads in a box. If the lettuce is to be shipped some distance it is put up in cases holding one barrel. -It is sold by the dozen heads. Leaf lettuce.—It was not until Eugene Davis, of Grand Rapids, Michigan, originated and introduced the Grand Rapids leaf lettuce that lettuce-forcing became popular in the middle West. The growing of head lettuce under glass did not prove a success in this region. The cry of "over-production" was heard soon after the forcing of leaf lettuce began and has continued until the present time. With the exception of short periods during the fall months of some years, there has been no over-production of this crop. Cultural methods. When leaf lettuce is sold by the pound, the usual practice is to grow three crops of lettuce followed by one of cucumbers or tomatoes. When the lettuce is sold by the dozen, more than three crops are commonly grown before the ground is given over to the other crop. Lettuce sold by the pound is usually grown to a much larger size than when it is sold by the dozen. The seed for the first crop of lettuce is sown from the first to the middle of August. It is sown in flats or in solid beds, usually broadcast but sometimes in rows. It is sown very thickly and if covered at all with earth the covering is very shallow, not enough soil being used to hide the seeds entirely from view. In warm weather one thickness of heavy brown paper or burlap is thoroughly moistened and placed over the seed as soon as it has been sown and watered. The covering is left on until the seed germinates which will vary from two to five days according to the amount of sunshine and degree of heat in the house. It should not be left on too long as spindling, nearly worthless plants will result. In cold, cloudy weather seeds sown in flats will germinate best if covered with glass for a few days after sowing. In about a week, in bright weather, and from ten days to two weeks in cloudy weather, the seedlings will be ready to prick off. This operation is tedious and requires deft hands and practice to do it well and rapidly. The plants are separated one from another, care being taken not to injure them, and transplanted into other flats or beds. They are spaced about 2 inches apart each way. All diseased and poorly rooted plants are discarded. The number of plants that can be pricked off in a day of ten hours will vary from 5,000 to 10,000 according to the skill of the operator. Some of the best growers sterilize the soil in which the seeds are sown and the seedlings grown. This not only insures plants free from disease but eradicates all weeds by destroying the vitality of the weed seed. All the care that is required for the seedlings is to keep the planthouse at the proper temperature, see that the soil is supplied with the right amount of moisture, remove all weeds which appear and stir the soil when necessary to keep it from crusting. The house in which the plants are grown should t>e well ventilated in order to guard against the damping-off of the seedlings. An occasional smudging with some form of tobacco is necessary to keep the green aphis under control. The cabbage butterfly frequently deposits eggs on fall-grown plants and these hatch into green worms which feed upon the lettuce in the beds. The butterflies should be killed when seen flying near the plants and should be guarded against as much as possible. In the fall when the days are long and many of them bright, lettuce will be large enough to set in the permanent beds about four weeks after it is pricked off. When lettuce is sold by the pound it should not be set closer than 7 by 7 inches or farther apart than 8 by 8 inches for best results. When sold by the dozen it can be set as close as 5 by 5 inches, although the best distance will depend upon the size of plants which are found most profitable to grow. The first crop of lettuce will be ready to cut, when sold by the pound, in six to eight weeks from the time the plants are set in the permanent beds. It should give a yield of at least three-quarters of a pound a square foot. The prices that the growers have realized for the first cuttings of lettuce have, during recent years, been rather low. The cost of growing this crop is small, however, as little fuel is needed for heating purposes. The second and third crops will require more time for their proper development than the first. They should give a heavier yield, however, and the prices secured are usually better. It is very important to have plants of the right size to set in the beds as soon as the ground can be prepared after a crop is out. To be able to do this, it is necessary to make frequent sowings of seed. In large greenhouse establishments, seeds should be sown every day or every other day, while in a small forcing-house a sowing should be made once a week throughout the season. No time should be lost between crops as time is money in the vegetable-forcing business. Considerable time can be gained by making a second transplanting for the second and third crops. The plants should be removed from the flats before they begin to crowd and placed in 2-inch pots. These pots should be plunged in the soil between the newly set plants in the permanent beds. The pots should be placed in the beds as thick again as the permanent plants are set. By following this plan, the plants can be grown to a much larger size without injury than is possible when they are grown only in the flats. Grand Rapids lettuce will stand a wide range of temperature without serious injury, but the lower the temperature the slower the growth and tougher the leaves, and the higher the temperature the more rapid the growth and more tender the leaves. A low temperature will produce heavy lettuce and a high temperature light lettuce. As long as thorough ventilation is given, little danger of injury from high temperature will occur, but high temperature and closed ventilators invite disaster. The best results are secured when the temperature is held at 45° to 50° at night until the lettuce has attained sufficient height, 8 to 10 inches, when it should be kept as near 45° as possible. The lowering of the temperature at the finishing of the crop will increase the weight considerably. If the houses are arranged so that it is possible to keep but one temperature, a night temperature of 45° to 48° is most satisfactory. The day temperature may vary greatly without injuring the lettuce if the ventilators and heating pipes receive proper attention. Ventilation should be given at all times during the day except when the weather is very cold or stormy. The heating pipes should be turned off whenever the heat from the sun is sufficient to give the proper temperature in the houses. Sub-irrigation is the most satisfactory method of watering lettuce. The water can be applied at any time through the tile without wetting the foliage. This method is not in general use because of the expense of installation. Water-tight benches or beds are essential for its successful operation. The overhead or Skinner system of watering is in common use, especially in large establishments. It is a great improvement over the old method of watering with the hose. It is not only more efficient but requires much less time and labor than the hose method. With it, water can be applied in any quantity desired and so gently that no baking of the soil will occur. Whatever the method of watering, the soil should be thoroughly soaked as soon as the plants are set. It should not be allowed to dry out, as the plants will be damaged by the resulting check in growth. When the water is applied to the surface, the watering should be done only on bright days and early enough in the day so that the lettuce leaves will dry off before night. Insects and diseases of lettuce. The one insect that is always ready to make its appearance is the green aphis. Fumigating regularly, at least once a week with tobacco stems or extract of tobacco will keep this insect under control. In case it secures a foothold and one smudging does not do the work, a second the following night will put the aphis under control. Tobacco dust scattered on the surface of the soil before the plants are set will help to repel the aphis. The cabbage worm is often troublesome, especially on the fall crop. Poisoning when the plants are small, and hand-picking when the crop approaches maturity, are the most practical remedies. Snails and slugs sometimes do damage, but do not as a rule appear when clean methods of culture are practised. Other insects, such as the white fly and black aphis, make their appearance on lettuce occasionally but seldom become serious. Among the more common diseases affecting lettuce is the drop or stem-rot. This rot acts very much like the damping-off of the seedlings. It is a fungous trouble and can be controlled to a large extent by thorough ventilation. Sterilization of the soil with steam sometimes becomes necessary in extreme cases. There are other less serious forms of rot affecting leaf lettuce, all of which can be kept under control, as a rule, by proper ventilation. Watering at night or during cloudy weather and high temperatures with closed ventilators are practices which will tend to induce attacks of rot. Another lettuce trouble of common occurrence is "rosette." This is a disease which attacks the roots, retarding and in some instances stopping the growth of the plants. Sterilizing with formaldehyde, used at the rate of two pounds to fifty gallons of water and applying one gallon of the mixture to each square foot of space, has frequently given good results. Sterilizing with steam, while more expensive, is more certain to prove effective. When the lettuce is allowed to suffer from the lack of sufficient moisture in the soil, it will often have the appearance of lettuce rosette. The grower should examine the soil carefully when the lettuce appears stunted in growth to be sure that the trouble is not lack of water instead of a diseased condition before going to the expense of sterilizing. Cutting and packing lettuce. There is a certain time in the development of leaf lettuce when it is of just the right size and of the proper degree of maturity to cut for market. This can be determined by the feeling and appearance of the lettuce. When ready to cut, the lettuce plants will feel firm when the hand is pressed gently on the top. If the edges of the leaves show a few brownish spots, the cuttings should be done without delay. The ability to judge just when the lettuce should be cut will be acquired by practice. Some of the large growers who make a business of shipping lettuce, pack it in barrels. It is placed with the top of the lettuce plants toward the outside of the barrel and, when filled, the barrel is covered with burlap. Fifty pounds are usually packed in an apple or cracker barrel and from seventy-five to ninety pounds in a sugar barrel. The lettuce is protected from frost in cold weather by lining the barrel with paper. In warm weather, holes are cut in the sides of the barrels to admit air and thus prevent heating. Boxes of different sizes but usually holding about a bushel are used by many growers. When the lettuce is to be shipped, the boxes are covered with wooden covers. When it is to be sold on a local market the lettuce is covered with paper or left uncovered. At Ashtabula, Ohio, all of the growers pack their lettuce in small baskets with stationary handles. Three and one-quarter pounds is packed in each basket and the lettuce and basket are covered neatly with paper. The kind and size of the package and the amount of lettuce put in is not of so much importance as the quality of the lettuce and the care with which it is prepared for market. Bright, clean, crisp lettuce will sell much more readily than tough, dirty lettuce. All dead or yellow leaves should be removed and all dirt washed off. Marketing. At some of the large forcing centers the growers are organized for the purpose of marketing their crops. One man is selected to do the selling of the entire output. The growers endeavor to put up a uniform grade of produce, and inspection is provided to see that no inferior stock goes in with that which is up to the standard. This plan insures better feeling among the growers and secures better returns for them than is possible when each grower sells his own products in competition with the other growers. A grower who has a local demand for all the lettuce he can grow has a decided advantage over the man who is obliged to ship his lettuce some distance. The person having a market within easy driving distance can, if he grows good stock and puts it up neatly, not only cut out the cost of shipping, the commission and much of the package cost that the man who must ship is obliged to pay, but he can also get a higher price for his lettuce, as he can put it on the market in better condition than is possible with shipped lettuce. Forcing of cucumbers. Cucumbers are forced very commonly as a spring and early summer crop in many regions. The New England growers devote a considerable area under glass to cucumbers in the fall and winter months. Eastern-grown cucumbers are sold in western markets at the time of the year at which most of the western growers are devoting all of their glass to lettuce or tomatoes. Some of the vegetable forcers in Illinois and farther west grow cucumbers in the fall and winter. Varieties. The long English type of cucumber is not popular for commercial purposes in this country although it is grown to some extent in private greenhouses. The American forcing-man prefers a type of cucumbers for forcing which is of the White Spine order. The first requisite of a good forcing cucumber is prolificacy. It should be from 8 to 10 inches long, even a foot in length not being objectionable, of regular and uniform diameter, not too thick, and free from what some term "neck" ends. It should be dark green in color. The fewer the seeds and the more poorly they are developed the better it will please the consumer. Cultured methods. Cucumber seed is planted in pots or flats about four weeks before the plants are to be set in the permanent beds. When planted in pots two to four seeds are placed in each pot. When planted in flats the seeds are sown rather thickly in rows about 2 inches apart. The flat-grown plants are pricked off, when large enough to handle, into pots, one plant in a pot, or into flats about 4 inches apart each way. The plants which are started in pots are not pricked off but they are thinned, when necessary, to not more than two in a pot. Cucumbers should be kept growing all of the time to get best results. In order to do this, they must be kept in a warm house. The night temperature should be above 60° and may run as high as 70°. The day temperature should run at least 10° higher than the night temperature and on bright days it can go still higher if the ventilators are open. The seedlings should never be allowed to dry out nor should they be watered too heavily as damping off is liable to occur when the soil is too wet. The watering should always be done on bright days. Cold draughts should be avoided as they induce attacks of mildew. Judicious ventilating will insure hardy plants. The distance apart the cucumbers should be planted depends on the method of training to be used. There are two distinct methods of training, the "A"-shaped trellis and the upright. When the trellis is to be used, the plants are set in rows from 10 to 16 feet apart and from 10 to 15 inches apart in the rows. When the vines are to be trained upright, the plants are set from 2 to 3 feet apart each way, one plant in a place. The trellises are made of wire or slats and wire which are run across 2 by 4 pieces of timber placed at wide intervals. When the vines are trained upright, strings are fastened to wires which are run above each row, one string to each vine. When training, the vines are simply twisted around the strings and the "feelers" attach themselves and thus hold the vines in place. Some growers use slender sticks, made especially for the purpose, on which to train the vines. The sticks are 1 ½ by ¾ inches and from 6 to 8 feet long. A piece about 4 inches in length is nailed across the bottom to keep the stick from sinking into the soil. The tops of the sticks are fastened to wires run parallel to the rows, one wire above each row. The vines are held in place by pairs of nails driven into the sticks at intervals of 12 to 15 inches. One of the nails of each pair is bent at right angles after being driven into the stick and the bent part is dropped onto the other nail after the vine has been placed between the nails. The pruning of the vines is similar, no matter which method of training is used. All laterals are cut back more or less. One to three female flowers are left on each lateral. Best results are usually secured when the laterals are cut beyond the first female bloom. Cucumbers in fruiting use an enormous amount of water if it is available. As soon as the supply of water in the soil becomes reduced below the amount required for the maximum growth of the plants and fruit, the number of short runty cucumbers will increase in proportion to the number of long ones. The Skinner system or any other similar system of overhead watering is ideal for cucumbers. Care should be taken to do the watering at a time when the foliage will dry off quickly, especially if mildew or any other fungous trouble makes its appearance. Aside from the fact that the soil must be rich in. plant-food, there is no other matter of as great importance as the water-supply. Whether the water be applied a little at a time and frequently or in larger quantities and at longer intervals is not of so much importance as the supply itself, which should be sufficient for the needs of the plants at all times. Pollination. Some form of artificial pollination is necessary for best results with the White Spine type of cucumber. Hand pollinating is very tedious and is seldom employed in large houses. The usual method is to place a hive of honey bees in the house and let them do the work. In large establishments several hives are required. One strong hive for each half-acre of cucumbers will be ample. When first put in, the bees are quite uneasy but they soon quiet down and make themselves very much at home. Insects and diseases of cucumbers. One of the most formidable insects attacking forcing-house cucumbers is the red spider. Some growers are obliged to fight this insect every season. The best way to combat it is to prevent its making an appearance. This can often be done by keeping all of the soil, walks and other places where there is enough dirt to permit of their breeding, moist at all times. When these little animals appear on the plants they can be driven off by spraying the plants thoroughly with water. To be effective, the water must be applied with force and directed against the under side of the leaves. Another insect which causes much damage to cucumbers is the striped cucumber beetle. The stink-bug may be included with" it, as the work of the two insects is very similar in its effect upon the plants. The most serious trouble with these insects does not occur when the plants are small, as they can be protected then, but when they are large. The vines which are damaged by these enemies resemble those injured or killed by the bacterial wilt. If the vines are killed by the wilt, all of the plant dies at one tune. When the damage is caused by the bugs, the upper part of the plant or a lateral branch will wilt and dies first, usually but not always followed in a few days by the wilting of another branch or the remaining part of the plant. No effective means has as yet been found for combating these insects. Some growers claim that by keeping the side ventilators and doors closed most of the time the bugs will not get into the houses. To keep them out in some places the ventilator openings would have to be screened. No crops which the bugs work on should be grown near the forcing-houses. When the insects once gain admittance to the houses, they are very difficult to eradicate. The stink-bugs lay their eggs in clusters on the leaves and these should be gathered and destroyed. The white fly is occasionally serious on cucumbers. The remedy is to fumigate with hydrocyanic acid gas, but as this gas is dangerous to both plant and animal life it is used only in extreme cases. The green and black aphis occasionally attack cucumbers in the forcing-house. The green aphis can be controlled by fumigating with tobacco. The black aphis usually occurs in patches and can be destroyed by applying strong solutions of tobacco or soap. Nematodes (eel-worms) often become very destructive to cucumbers. As they work entirely on the roots, their presence is indicated by a weak and stunted growth of the vines. There is no cure for a vine once attacked. Sterilizing the infested soil with steam is the usual method of eradicating them. It is not safe to set plants in an infested soil which has not been sterilized. Cucumber wilt is a bacterial trouble which often destroys a crop in a few days. There are no satisfactory means of combating it when it becomes established. It is most likely to occur on plants which are weakened in some other way, as by having too much water applied or too little heat. Plants which are kept growing vigorously are seldom attacked by the wilt. The downy mildew is very partial to cucumbers and often does serious damage. Cold draughts should be avoided as much as possible. Frequent spraying with bordeaux will keep the trouble in check. Another less common but sometimes serious cucumber disease is anthracnose. Bordeaux is the remedy for this disease. Root rot of cucumbers is of occasional occurrence and may be prevented by sterilizing the soil with steam. Grading and packing cucumbers. In sorting cucumbers for market they are made into at least two grades. The culls are seldom placed on the market. About the same kinds of packages are used in which to pack cucumbers as are used for lettuce. They vary in size from the sugar barrel to the small basket holding from two to two and one-half dozen specimens. When handled in winter they are usually packed in paper-lined boxes or baskets. Forcing of tomatoes. Fig. 1549. Tomatoes are forced under glass at all seasons of the year except during the time they are ripening most freely in the field. The largest area of glass is devoted to this crop in the spring and early summer. There is also quite a large area grown during the fall and early winter. Only a very few growers force tomatoes in the midwinter months. Varieties. There is a difference of opinion among growers as to which varieties are best for forcing. In a general way it may be said that for the fall crop the varieties having medium to small fruits are most desirable. Some growers also prefer these kinds for the spring and early summer crop. Other growers like the large fruiting sorts, such as the Stone and Globe for the summer crop. Some markets prefer pink or purple varieties and others red sorts. Some of the requirements of a good forcing variety are: prolificacy, smoothness in form, meatiness and good flavor. If the fruit is to be shipped it should not be too tender of skin. Some varieties crack more readily than others and those that are inclined to crack should be avoided. Other qualities not lacking, those kinds which are most resistant to disease are to be preferred. Some varieties need less attention in the matter of hand pollinating than others. This is a desirable character and should be given consideration when selecting a variety for forcing purposes. Cultural methods. For the fall crop the seeds should be sown in June. The best results are secured from this crop when the fruit is all set and well grown before cold weather begins. The crop should begin ripening about the time killing frosts occur and the bulk of the crop should be off by the first of January. For the spring and early summer crop the seed should be sown in time so that the plants will be ready to set in the permanent beds by the first of March. If a temperature of 60° can be maintained at night, the plants can be grown in two months from the time of the sowing of the seed. Plants set in the permanent places the first of March should ripen fruit about the first of June and should be through fruiting by the middle of August or a little before. The care of the seedling plants is about the same for the fall and spring crops, except that owing to the difference in the amount of sunshine they can be grown more quickly and easily in summer than in winter. For either crop the seeds are sown thickly in flats or beds and in rows about 2 inches apart. As soon as they are sown the seeds should be covered with glass, paper or burlap to keep the surface of the soil moist. When large enough to handle, the seedlings should be pricked off into flats or beds, spacing the plants 2 inches apart each way. Before they begin to crowd, they should be transplanted again, this time into 2- inch pots. A third handling should be made in about three weeks when the plants should be transferred to 4- or 5-inch pots. From these pots they should be transplanted to the permanent beds. A temperature of 60° or 65° should be maintained in the plant house at night and at least 10° higher on bright days. Careful attention to watering and ventilating is very important. Plants which are given too much water or which grow in a house in which the ventilators are seldom open will be readily attacked by diseases. Plants which are properly grown are disease-resistant to a considerable extent. The spacing of tomato plants which is practised by different forcers is much more nearly alike than is the case with cucumbers. The plants are seldom set closer than 1 ½ feet nor farther apart than 4 feet. Two by 2 feet or 1 ½ by 3 feet are good distances. Nearly all tomatoes are trained upright and usually to one stem. When two stems are used, the tops are trained apart a foot or more, making the plant form the shape of a partly opened fan. Strings run from the foot of the vines to wires run above the rows are the usual means of support. By twisting the vines around the supporting strings, only a small amount of tying will be necessary. All laterals or side branches should be removed when small if the plants are trained to one stem. If they are to be trained to two stems, the lowest strong lateral should form the second stem. The lateral just above the first blossom cluster is usually the strongest. All other side branches should be removed. The pruning requires careful attention and consumes much time. If the laterals are allowed to grow to a large size before they are removed, it will, not only require more time to cut them off but they will take needed strength from the main branch. Pollination. As honey bees do not work on tomato blossoms it is necessary to do more or less hand pollinating, the amount depending on the time of the year, the number of blossoms open and the varieties grown. If the weather is such that the ventilators can be kept open wide most of the time during the day, frequent and systematic jarring of the plants will be fairly satisfactory. Artificial pollination is more necessary when the plants first begin to bloom than when the amount of bloom is abundant. Some of the English types of forcing tomatoes do not require much attention in the matter of pollinating. However, it is better to be on the safe side and do more pollinating than necessary rather than not enough. The earners-hair brush is used by some growers and the wooden spoon and spatula with handles 15 to 18 inches in length are used by other growers as a means of transferring the pollen from one flower to another. Grading and packing tomatoes. Unless they are to be shipped a long distance forcing-house grown tomatoes should not be picked until they show considerable color. The more nearly mature the fruits are when taken from the vines, the better the quality. Picking should be done every other day or at least three times a week. The fruit should be handled with care to avoid bruising, as injuries impair the keeping quality of the fruit. In grading, unless the fruit is unusually rough or too variable in size, only one grade need be made for the average market. All very rough and otherwise inferior fruits should be withheld from the market. Some growers make a fancy grade for special trade. This stock should be of medium and uniform size, even in color and very smooth. The hotels and clubs which give orders for such stock are willing to pay an extra price for it. Tomatoes are handled mostly in baskets. These are seldom larger than a half bushel and usually considerably smaller. The basket used by the Ashtabula growers is the same as they use for lettuce and holds ten pounds of tomatoes. A very satisfactory package for use in warm weather is the four-basket carrier or crate. The baskets which are put in this carrier hold five pounds each. When properly selected as to size, color, and smoothness, tomatoes packed in this container are very attractive. The chief objection to then- use is that they are too much like the package used by the southern tomato-growers and thus not distinctive enough for the forcing-house tomatoes. During cold weather or when the tomatoes are to be shipped a long distance, each fruit should be wrapped in paper to protect it from the frost and to prevent bruising. Dealers who have not handled forcing-house-grown tomatoes are sometimes slow to pay the price which the stock, if well grown, graded and packed, should demand. When they have once learned that forcing- house-grown tomatoes are of superior quality and will stand up much better than those which have been shipped a long distance and of necessity must be picked green or nearly so, they are usually willing to pay much more for the forcing-house-grown than for the outside-grown tomatoes. Forcing of radishes. Radishes have been forced by many growers but they have not become generally popular. This is no doubt due largely to the fact that the growing of them and preparation for market necessitates a large amount of hand labor; and the requirements of the crop are exacting. The turnip-shaped sorts are most satisfactory for forcing in the forcing-house. The seed should be sown thickly in rows which should be marked 4 inches apart and about % inch deep. The Skinner system of watering is very satisfactory for radishes if the watering is properly done. The soil should be kept moist but not too wet on the surface. The watering should be done only when the weather is bright. Some growers have found it more satisfactory to allow the radishes to remain quite thick in the rows until a part of them are large enough to market and then pull the marketable ones and allow the others to develop, than to thin them enough when they are small to permit the radishes to mature nearly at one time. This method of thinning will enable the gardener to grow many more radishes hi a given area than when the old method is used. Some of the essential factors in successful radish forcing are: good seed, carefully sown; an abundance of light; plenty of ventilation; sufficient water and heat to keep the plants growing rapidly but not enough to cause damping-off; neatness and cleanliness in bunching, washing and packing. Other forcing crops. Space will permit only of a classification of other forcing crops than those previously mentioned. Nearly all kinds of vegetables which are grown in the open can be grown in the forcing-house. Whether it is practicable or not to force a vegetable in a commercial way depends principally on two things: cost of production and market demand. The following lists include practically all vegetables which are forced commercially, either extensively or to a limited extent. The vegetables included in these lists are divided into two classes, the "cool" and the "warm" plants. By cool plants is meant those for which the proper night temperature is from 40° to 55° and by warm plants those for which the night temperature should be from 55° to 70°. With either class of plants the day temperature on bright days should be at least 10° higher than the night temperature. "Cool" forcing vegetables: Asparagus Beet Carrot Cauliflower Celery Cress Lettuce Onion Parsley Pea Radishes Rhubarb Spinach "Warm" forcing vegetables: Bean Cucumber Eggplant Muskmelon Pepper Tomato C. W. Waid. The forcing of fruits. The forcing of fruits under glass has increased considerably in recent years and particularly so in the private establishments. Grapes probably occupy more space than any other class of hothouse fruits. Records of cultivating the vine may be traced back some thousands of years. Nevertheless, the greenhouse grape-vine has not been improved to the same extent through systematic hybridizing that many other fruits have been. Some of our oldest varieties still hold a prominent place in the forcing-houses. Some worthy claimants have been added to the list from time to time. Madres- field Court was raised over forty years ago by crossing Muscat of Alexandria with Black Morocco, producing a distinct Muscat grape with the Morocco coloring. Of later introduction may be mentioned Lady Hutt, Appley Towers and a few others which have been tested and have found favor with many growers. Another account of raising grapes under glass will be found in the article Grape. Forcing of grapes. The vine is of easy propagation. Different methods may be applied for reproducing young vines, such as cuttings or by eyes of ripened wood. Inarching and grafting may also be resorted to. However, the general method of raising young vines is from single eyes. It is advisable to choose wood of the previous season's growth or, when pruning back the vines, to take thoroughly ripened wood with plump eyes. If not ready for propagating, the wood may be heeled in a cool house until needed. The month of January is best for this purpose, for then there is usually a steady bottom heat, which is necessary. A bottom heat of 70°, with a temperature in the house of 65°, is most satisfactory. Furthermore, January-propagated plants allow for a long season to grow on the canes. In preparing the eyes for propagation, about l/i inch of wood on each side of the eye is sufficient. Make a cut on the opposite side from the eye a trifle deeper than the bark, which will callous in a short time after it is placed in heat and roots will emit in two or three weeks. These eyes may be placed in pans, flats or singly in 3-inch pots; when time is no serious object, the pots are decidedly to be preferred, as the young vine roots are very brittle. In preparing the pots to receive the eyes, half fill them with fibrous soil and fill the top with a fairly sharp sand, enough to cover the wood with the eye just level with the sand. The advantage of having the soil in the bottom is that the roots will strike down and the plants may be repotted, when ready, without a check. They must be kept growing through the summer in a warm moist house and repotted when necessary. Inarching may be found valuable at times, particularly if there is a variety in the house that is not desirable. The operation is fairly simple. There are different methods of marching, although the most successful is with the young growing wood. For example, to inarch a variety with a permanent vine, preparations should be made the year previous. Grow the variety desired in a pot, then ripen off as for planting. Whenever the vines are started into growth, bring in the pot vine intended for inarching, about ten days after the heat has been placed in the grapery. Otherwise the pot vine will start into growth before the permanent vine. It is advisable to select shoots of about the same strength, if possible. The shoot that is operated on should be as near the base as possible. To inarch them is just a matter of bringing the two shoots together and tying with raffia. When the cion has united with the green growing shoots, which will be in a short time, gradually cut it away from its own root; also pinch the stock back by degrees to increase the strength of the cion. Usually the cion will grow away rapidly and produce a strong cane by fall so that when pruning time comes the following winter the old cane may be cut away and the new variety will take its place. Hybridizing. In hybridizing with the aim to produce new varieties, it is best to select a fairly strong-growing variety for the female parent, choosing the rich Muscat pollen for the male parent. No estimate can be formed as to results from a true cross, as many different varieties will appear. Grapes will produce an abundance of pollen and great care must be taken to avoid self- fertilization. Nature protects the pollen of the grapevine by a cap that surrounds the pistils and stamens, and when the pollen is ripe for distribution the caps are pushed off by the expansion of pistils and stamens, insuring pollination. To cross-pollinate one variety with another, measures should be taken in advance of natural development to prevent self-pollination. Select the bunch to be operated upon a few days before it would begin to flower. Cut away the larger part of the flowers, leaving a dozen or fifteen to be crossed with other pollen. Then secure this bunch in a fine muslin bag, which will prevent any insects from distributing undesirable pollen upon it. The muslin will allow sufficient air for the berries to set, after which it may be removed. The bag is placed around the bunch a day or so before the cap is ready to be dislodged, and careful watch must be kept when the cap begins to loosen. Have a pair of very fine plyers or pincers ready and remove the cap by force, then immediately cut away the stamens before the pollen has time to ripen. This must be executed with great care as the flowers are very delicate. Sometimes the flowers cannot all be operated upon at the same time. If so, place the bunch again in the bag and repeat the above process. When the stamens have been removed, apply the pollen chosen for the cross. This is best applied to the stigma with a camel's-hair pencil. Repeat until the whole have been gone over carefully. By using these precautions, the bunch cannot become contaminated with undesirable pollen. Grape seed will germinate very readily, although it should be sown soon after ripening as its germinating power is weakened if kept any great length of time. Virus borders. Good drainage is absolutely necessary for the successful cultivation of grape-vines. They will not resent an abundance of water while in active growth, in fact they demand it, but a border which the water cannot pass through freely will be found a serious difficulty. It is well in finding a location to choose, if possible, a site on elevated ground, as the drainage from the border can be carried off with less expense than in a low place, without the trouble of the drain-pipes becoming stopped up. A vine border will last for years and the advantage of a well-made border, even though expensive in building up, will be manifest in the better fruit produced. A grapery may be supplied with both outside and inside borders, although it is not necessary. Neither would it be advisable for early forcing, for the reason that many of the roots would be out in the cold soil at quite a contrast from the ones inside. But for mid- season or late, there is no objection to this method. In fact, vines that have access to an outside border will keep healthy and vigorous several years longer than when confined wholly inside. However, an inside border will last for at least ten or fifteen years. This must be decided before the house is built as, for an outside border, the walls must be erected on arches to allow the roots access outside. One advantage of this method is that the vines do not require such close attention as when depending entirely upon the inside border. However, at present the larger number of graperies are built with inside borders only. The first thing to be done is to excavate at least 3 ½ to 4 feet for the border. Assuming it to be a span-roof house, lay a drain down the center, allowing enough fall to carry off the water. Use 3-inch pipes and provide openings along every 20 feet or so to take away the water. After the drain is complete, a coat of rough concrete may be placed over the bottom, which will prevent any of the vine roots from penetrating into the subsoil. Over this add a foot or 18 inches of drainage, such as broken stone or brickbats,—anything that will insure a free passage for water. From the drainage to the surface level, there should be about 2J^ feet or a trifle over for soil. In some localities it is difficult to secure a grade of soil best adapted for vine growth, although grape-vines will thrive in different kinds of soil, if not too sandy or too clayey. A good loamy soil is best, virgin loam preferred; or loam that has been in pasture three or four years may be plowed and placed directly into the border. The grass fibers are of great benefit. The vines would make a very satisfactory growth for a year or so without any fertilizing ingredients added. However, this would not be a wise policy and fertilizers of a lasting quality should be used. On that account, farmyard manure should not be used. All fruits require potash, phosphoric acid and nitrogen and therefore these manures should be applied. Do not apply the fertilizers too heavily. It is a simple matter when the vines become thoroughly established to feed from the surface. Bone is one of the very best ingredients to place in the grape border. This may be used in a coarse state or that known as ½ -inch bone at the rate of forty or fifty parts of solid to one of bone. Potash may be used in the shape of hardwood unleached ashes, a trifle less in quantity than that recommended for the bone. Toward the surface, a quicker-acting complete fruit - fertilizer may be used. Such a border should grow and produce grapes for many years. A span-roof house running north and south is recommended, as a certain amount of sunlight will be had 1551. Pot-grown pear on both sides, whereas in a house tree in bloom. running east and west, very little sun will strike on the north side. Either curvilinear or straight span answers the purpose for a private establishment. Planting vines. Vines may be planted either in fall or early spring. Early fall-planted stock appears to come away more freely and break stronger than spring planting. Plant the canes about 4 feet apart; there is nothing gained bv too close planting. It is immaterial whether one-year- old plants are selected or two-year-old, providing they are thrifty strong canes. They should be shortened back to 2 feet to insure strong growths from the remaining buds, since, if a much longer length of cane is left, they will break away unevenly and weakly. Before planting, all the soil from a ball should be removed and the roots straightened out. Spread the roots out evenly on the border, cover with about 3 inches of soil and firm the soil well around them. General treatment for forcing. Grape-vines respond to the forcing treatment readily, although a newly planted grape-house should be brought along with little or no forcing the first season. There would be no advantage in forcing them, as they should not be allowed to produce fruit until the second year, when they will be thoroughly established. However, assuming that the vines are established and grapes are needed from the first to the tenth of May, the house must be started by the middle of December with a temperature of 45° to 50° at night, with a rise of 10° to 15° by day, according to weather conditions, and gradually increasing so that when the grapes are in bloom the temperature will be 65° at night and 75° to 80° by day. If a supply of grapes is demanded up to Christmas or the New Year, three compartments must be accommodated, the midseason house being started two months later and the late house about the first of April. A very important point to be considered is to give the border a thorough watering, for while the vines are at rest they are kept fairly dry. Ventilation or airing is very important, for unless this is attended to carefully serious trouble will follow, such as mildew, red-spider and the like. The heat should be allowed to rise gradually until the maximum is reached in the morning, then kept as steady as possible and toward evening gradually lowered to night temperature. The best method of growing vines under glass is the single-rod spur system. The spurs should be 15 or 18 inches apart on each side of the rod. Then disbud to one shoot for each spur. As the young growth advances, it must be trained in place by degrees, as the young shoots are very brittle and if brought down too quickly are liable to snap off. The next step is pinching the shoots. The aim is to allow enough growth to cover the trellis with foliage but to avoid crowding. A fairly safe method is to stop the shoot at the second or third leaf beyond the bunch, also pinch all lateral growths at the first leaf. Probably one of the most anxious times with the man in charge is while the vines are in bloom or setting their fruit. Certain varieties will set their fruit much more freely than others. The Muscat family, as a rule, is a bit backward in that respect. A safe method to follow is a steady temperature with a fairly dry bracing atmosphere so that the pollen can distribute itself freely. By gently tapping the bunches around midday, they should set freely. When the berries are about the size of garden peas, they are in condition for thinning. This is a tedious operation, requiring time and patience. The bunch must never be handled with the fingers. Either a stick with a fork or a straight stick to lift the shoulders of the bunch while thinning should be used. The aim is to cut away enough surplus berries to allow the remainder to swell to full size, so that when full grown and ready to cut the bunch will keep the same perfect shape when set on the dinner-table. Grape-vines, when in a healthy, vigorous condition, are rank feeders. There is no better time to apply food than just after the grapes are thinned and again as they take on their second swelling after the stoning period. This may be applied in the shape of liquid manure water or a complete chemical fertilizer. The grower must use his own judgment in regard to quantity, as so much depends on conditions. A healthy vine can withstand more food than one less robust. Nevertheless, it is much better to feed lightly than too heavily. A moist humid atmosphere is necessary for grapes while they are growing or from the time they are started into growth until they begin to color, from which time a drier bracing air will be of advantage. At this stage, bottom air may be admitted by degrees during the day, and later, or when ripe, keep bottom air on day and night.
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References
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963
