The theory of ringing is simple. Una.s.similated sap pa.s.ses from the roots of the plant to the leaves through the outer layer of the woody cylinder. In the leaves this raw material is acted on by various agents, after which it is distributed to the several organs of the plant through vessels in the inner bark. When plants are ringed, the upward flow of sap is continued as before the operation, but the newly made food compounds cannot pa.s.s beyond the injury, and therefore the top of the plant is supplied with an extra amount of food at the expense of the parts below the ring. The extra food produces the results noted.
It turns out in practice that ringing is usually harmful to the plant, as one might expect from so unnatural an operation. Injury to the plant arises from the fact that parts of the vine are starved at the expense of other parts; and because, when the bark is removed, the outer layers of the woody cylinder dry out very quickly and thus check to some extent the upward flow of sap through evaporation from the exposed wood. Thus, not infrequently, the plant"s vitality is seriously drained. Nevertheless, vineyards may be found in which ringing has been extensively practiced many seasons in succession and which continue to yield profitable crops, the growers having learned to perform the work of ringing so as to injure the vines but little.
Ringing without harm to the plant depends much on the way in which the vines have been pruned. For instance, if the vines are pruned to the two-arm Kniffin method, the ringing of bark should be done from both arms just beyond the fifth bud. Thus, the ten buds left on the vine produce enough leaf surface to supply the food necessary to keep the vine in vigorous condition. When the four-arm Kniffin method is used, the two top arms only are ringed, and even so three or four buds must be left on each for renewals. Whatever the method of training, it will be seen from these examples that some unringed wood must be left to the vine with which to supply leafy shoots to support the vine. Some growers ring their vines only every other year, thus giving them an opportunity to recover from whatever loss of vigor they may have sustained in the season of ringing.
Several other considerations are important in ringing: First, the vines must not be permitted to carry too large a crop. Again, the amount of fruit on the ringed portion of the vine must depend on the amount of leaf surface not only of the plant but of the ringed arms, each ringed arm acting somewhat independently so far as its crop is concerned. If too many cl.u.s.ters are left on the ringed arms, it always follows that the fruit is inferior and often worthless. Lastly, all fruit between the rings and the trunk must be removed, for it does not mature properly and so adds only to the drain on the plant"s vitality.
As to the results, it is certain from the experiments that have been conducted and from the experience of grape-growers, that the maturity of the fruit is hastened, and berries and bunches are larger when the ringing has been done intelligently. Many growers hold that fruit produced on ringed vines is never quite up to the mark in quality and in firmness of fruit. There seems to be a difference in opinion about this falling off in quality, however, although unquestionably, choice sorts, as Delaware, Iona and Dutchess, suffer more or less in quality.
It is commonly agreed, also, that varieties, the fruits of which crack badly, as the Worden, suffer more from cracking on ringed than on unringed vines.
Experiment and experience prove that the best results of ringing are obtained if the work is done when the grapes are about one-third grown. Of course the exact time depends on the season and on the variety. The operation is variously performed and is easily done with a sharp knife, but when large vineyards are to be ringed the grower ought to provide himself with some simple tool. Paddock, in the bulletin previously mentioned, pictures two of these tools and these are reproduced in Fig. 52.
[Ill.u.s.tration: FIG. 52. Tools used in ringing grape-vines are shown in 1 and 2; while 3 and 4 show ringed vines at the beginning and the close of the season.]
In conclusion it must be said that it is doubtful whether the gains attained by ringing offset the losses. The practice is chiefly of value only when exhibition cl.u.s.ters of grapes are wanted or when it is necessary to hasten the maturity of the crop. Always, however, the work must be performed with intelligence and judgment or the losses will offset the gains.
BAGGING GRAPES
In some localities bagging is considered an essential to profitable grape-growing. The bags serve to protect the grapes against birds. In some grape regions vineyards suffer more from the depredations of robins and other birds than from all other troubles. Grapes bearing small berries and having tender pulp and those which sh.e.l.l most readily from the stem suffer most. Of standard sorts, Delaware is probably more enticing to robins than any other variety. There is only one way of preventing damage to grapes from birds and that is by bagging the cl.u.s.ters.
Bagging is also an effective means of protecting the grape from several fungi and insects. In home plantations or small commercial vineyards, bagging the bunches often eliminates the necessity of spraying for fungi and for most of the insects that trouble the grape.
Because of the warmth afforded by the bags, bagged grapes ripen a little earlier and are of somewhat higher quality than those not bagged. Grapes bagged are protected from early frost, thus prolonging the season. Grapes that have been protected from the elements during the summer are more attractive than those exposed to the weather, since the fruits are free from weather marks and present a fresh, bright appearance, which puts them in a grade above unbagged grapes.
Bagging often enables the grower to sell his crop as a fancy product.
Grapes are bagged as soon as the fruits are well set, the sooner the better if protection against fungi is one of the purposes. Under no circ.u.mstances, however, should the cl.u.s.ters be bagged while in blossom. A patent bag made for the purpose may be purchased or, serving equally well, the common one and one-half and two-pound manila bags used by grocers prove satisfactory. One of the patent bags which is known as the Ideal Clasp Bag has a metal clasp attached to the top for securing the bag in place over the cl.u.s.ter. In using the grocer"s bag, before it is put in place the corners of both the top and bottom are cut off by placing several bags on a firm level surface and using a broad-shaped chisel. Cutting off the corners of the top enables the operator to close the bag neatly over the cl.u.s.ter, while cutting off the corners of the bottom furnishes a means of escape for any water that gets in the bag. In putting the bag in place, the top is pinned above the lateral from which the bunch hangs, and must not be fastened about the small stem of the cl.u.s.ter, as the wind blowing the bag almost invariably breaks the cl.u.s.ter from the vine. The largest pins to be purchased in dry-goods stores are used in pinning the bags. The bags remain until the grapes are picked. Wet weather does not injure bags and seemingly they grow stronger with exposure to sun and wind.
The cost of the bags and the work of putting them on is no small item.
To secure the best results, the work must be done at the period between the dropping of the blossoms and the formation of the seeds, when the grapes are about the size of a small pea. This is a busy time for the grape-grower, which adds to the cost. When the work is conducted on a large scale, the cost is about two dollars a thousand bags, this figure covering both the cost of bags and labor. Women do the work more expeditiously than men and soon become very skillful in putting on the bags. Despite the trouble and cost of bagging, growers seeking to produce a fancy product find that the expenditure proves profitable.
WINTER-PROTECTION OF GRAPES
With a little care as to winter-protection, grapes may be grown profitably in northern regions where, without protection, the vines are killed or injured by low temperatures. Indeed, it is little short of amazing how well grapes can be grown in northern regions where nature wears a most austere countenance in winter, if hardy early sorts are planted in warm soils and situations, and the vines are covered in the winter. Occasionally one finds grapes grown profitably in commercial vineyards in the northern states in regions where protection must be given to prevent winter-killing, the extra work of giving protection being more than offset by the high price received in local markets for the fruit.
In all locations in which winter-protection must be given, several other precautions are helpful or even necessary. Thus, cultivation must cease early in the season, and a cover-crop be sown to help harden and mature the vines. The grapes, also, must not be planted in soils rich in nitrogen, and nitrogenous fertilizers must be applied with care. The pruning should be such as does not induce great growth.
These simple precautions to hasten maturity often suffice in climates where the danger of winter-killing is but slight, but where danger is imminent the vines must be covered either by wrapping or by laying down. Wrapping with straw may suffice for a few vines, but when many vines are to be protected, laying them down is cheaper and much more effectual.
By laying down is meant that the vines must be placed on the ground and there be protected by earth and snow or other covering. It is obvious that to protect thus, the vines must receive special training; otherwise the trunks may be too stiff for bending. Some method of training must be chosen in which renewals may be made rather frequently from the ground so that if the trunks become large, clumsy and unpliable, a more manageable trunk can be trained. If the provisions for renewal are kept in mind, any one of the several methods of training grapes explained in Chapter VIII on training may be used.
Laying down must be preceded by pruning, after which the arms and trunk are loosened from the wires and bent to the ground. Bending is facilitated by removing a spade full of earth from the side of the vine in the direction in which the vine is to be bent. The trunk is then laid on the earth and sufficient soil placed on it to keep it in place on the ground. If the danger of winter-killing is great because of the tenderness of the variety or the austerity of the climate, it often becomes necessary to cover the whole plant lightly with earth.
Small growers often make use of coa.r.s.e manure, straw, corn-stalks or similar covering, in which case the vines are held on the ground by fence-rails or other timbers; but protecting with material that must be brought into the vineyard is expensive and not more satisfactory than earth.
The vines can be put down at any time after the leaves drop and before the earth begins to freeze. It is more important that the vines be taken up at the proper time in the spring. If uncovered too early and cold weather follows, injury may result and more harm be done than if the vines had not been covered. On the other hand, if the earth is permitted to remain too long, foliage and vine are tender both to sunshine and frost. A grape-grower in New York who has had much experience in laying down vines in a vineyard of some thirty or forty acres says that the work may be done at a cost of $6 an acre at the average wage paid for farm-labor. It must be expected in a large plantation, no matter how well the work of covering is done, that occasionally a trunk will be broken, making it necessary to graft the vine if a shoot does not spring up from below the break.
RIPENING DATES AND LENGTH OF SEASON FOR GRAPES
Every grape-grower should know when his varieties may be expected to ripen and the length of season that they will keep. The commercial fruit-grower by all means should have this information. It is not sufficient that he know only roughly at what season his varieties ripen; for, to take the turn of the market, he must know exactly when a variety will ripen and how long it will keep. He needs this information, also, that he may distribute his labor better throughout the picking season.
Unfortunately, the data as to ripening time given by originators and introducers of varieties are not always reliable. This untrustworthiness of data is readily accounted for in several ways: First, growers do not generally agree as to when grapes are ripe nor as to how long they are fit to eat. Again, much confusion as to when varieties ripen and how long they will keep arises from the fact that grapes ripen at different times in different places, and it is difficult for the grape-grower in Maine to make allowance in season for varieties, the time of ripening of which is given for Maryland.
There are also other causes than the seasonal differences in grape regions for variability in ripening time; thus, some soils are warmer and quicker than others, and on these grapes ripen earlier.
Application of nitrogenous fertilizers may delay the period of ripening somewhat. Grapes ripen perceptibly earlier on old plants than on young ones. Lastly, every vineyard in a particular region has its own particular climate caused by the lay of land, nearness to water, air currents and alt.i.tude which cause small differences in ripening.
The following table taken from Bulletin No. 408 of the New York Agricultural Experiment Station gives the ripening dates of grapes at Geneva, New York. It is necessary that the reader know something about the conditions affecting the ripening time at Geneva. The lat.i.tude is 42 50" 46". The alt.i.tude is 525 feet above sea level. The vineyard lies a mile west of a relatively large body of water. The soil is a cold heavy clay which must delay ripening time somewhat. The land is level. The data are given as an average for three seasons, 1913-1915.
The figures given for "weeks in common storage" cover a variable number of years, but for all varieties three or more years. The grapes, after being picked, were at once placed in common storage in a room on the second floor of a building. There conditions were not ideal, and no doubt the season of storage would have been prolonged somewhat had the fruit been kept in a better storage-room.
TABLE V.--SHOWING THE RIPENING TIME OF GRAPES
=====================================================================WEEKS INCOMMONVERYMID-VERYSTORAGEEARLYEARLYSEASONLATELATE -------------------+----------+-------+-------+--------+------+------ Agawam*America*Barry28*Beacon7*Bell8*Berckmans21*Black Eagle18*Brighton20*Brilliant11*Brown6*Campbell Early12*Canada17*Canandaigua20*Carman17*Catawba21*
Champion6*Chautauqua10*Clevener13*Clinton21*
Colerain8*Columbian Imperial7*Concord8*Cottage5*Creveling16*Croton23*Delago25*
Delaware15*Diamond10*Diana17*
Downing*Dracut Amber9*Dutchess23*Early Ohio*Early Victor11*Eaton6*Eclipse7*Eldorado17*Elvira18*Empire State24*Etta15*
Eumelan17*Faith11*Fern Munson11*
Gaertner17*Geneva22*Goethe18*
Gold Coin10*Grein Golden12*Hartford8*Headlight8*Helen Keller26*Herbert27*Hercules13*Hicks10*Hidalgo12*Hosford6*Iona13*Isabella11*Janesville13*Jefferson18*
Jessica12*Jewel12*Kensington19*King*Lady Washington16*Lindley27*Lucile9*Lutie4*McPike7*Manito7*Martha10*Ma.s.sasoit16*Maxatawney12*Merrimac31*Mills29*Missouri Riesling6*Montefiore9*Moore Early6*Moyer9*Nectar10*Niagara10*Noah10*Northern Muscadine9*Norton7*
Oporto12*Ozark11*Peabody*Perfection8*Perkins*Pierce*Pocklington*Poughkeepsie15*Prentiss16*Rebecca18*Regal16*Requa30*Rochester7*Rommel10*Salem27*Secretary25*Senasqua13*Stark-Star10*
Triumph15*
Ulster21*Vergennes28*Wilder11*Winch.e.l.l6*Worden6*Wyoming9*=====================================================================
[Ill.u.s.tration: PLATE XXII.--Lindley (1/2). Lucile (1/2).]
CHAPTER XVII
GRAPE BOTANY
The grape-grower must know the gross structure and the habits of growth of the plants properly to propagate, transplant, prune and otherwise care for the grape. Certainly he must have knowledge of the several species from which varieties come if he is to know the kinds of grapes, understand their adaptations to soils and climates, their relation to insects and fungi, and their value for table, wine, grape-juice and other purposes. Fortunately, the botany of the grape is comparatively simple. The organs of vine and fruit are distinctive and easily discerned and there are no nearly related plants cultivated for fruit with which the grape can possibly be confused. Botanists, it is true, have dug pitfalls for those who seek exact knowledge as to the names and characters of the many species, but, fortunately, each of the cultivated species const.i.tutes a natural group so distinct that the grape-grower can hardly mistake one for another in either fruit or vine.
PLANT CHARACTERS AND GROWTH HABITS OF THE GRAPE
A grape plant is a complex organism with its many separate parts especially developed to do one or a few kinds of work. The part of a plant devoted to one or a group of functions is called an organ. The chief organs of the plant are the root, stem, bud, flower, leaf, fruit and seed. Flowers and leaves, it is true, develop from buds and the seeds are parts of the fruits, but for descriptive purposes the vine may well be divided into the parts named. These chief organs are further divided as follows:
_The root._
_Root-crown_: The region of the plant in which root and stem unite.
_Tap-root_: The prolongation of the stem plunging vertically downward.
_Rootlets_: The ultimate divisions of the root; usually of one season"s growth.
_Root-tips_: The extreme ends of the rootlets.
The roots of some species of the grape are soft and succulent as those of _V. vinifera_, while the same organs in other species, as in most American grapes, are hard and fibrous. They may also be few or numerous, deep or shallow, spreading or restricted, fibrous or non-fibrous. The structure of the root thus becomes important in distinguishing species.