Courtesy Campbell Soup Co. Figure 6.—Cultivating and side-dressing tomatoes.Figure 6.—Cultivating and side-dressing tomatoes.
Another critical stage in tomato growth comes when much fruit has been set in the clusters and demands upon plant and soil are especially heavy. At this stage, side dressing with nitrogen is helpful in maintaining plant growth and providing resources for growth and maturing of fruit. On sandy or nutrient-deficient soils, more than one side dressing may be advisable. Sodium nitrate is commonly used but other materials are suitable after the soil has warmed up. Side dressing with fertilizer in solution has been recommended recently by Tiedjens of New Jersey.
A tomato crop may be much poorer than the seed from which it grows but it can be no better.
The tomato seed is short-oval and flattened in shape, covered thickly with short silky hairs. The embryo or baby plant is coiled in a spiral and imbedded in the endosperm (reserve food supply). Three or four years is generally given as the life of the seed but it often remains viable much longer—up to 10 or 12 years in extreme cases. Good seed should germinate 85% to 90%.
Tomato seed sprouts readily, requiring fairly warm temperature, say, 70° to 75° F. for best results. It germinates very slowly at 40° to 50° F.
Being a major vegetable crop, the tomato has received much attention from plant breeders. Objectives sought include good cannery type, resistance to the fusarium wilt and other diseases,better greenhouse forms, improved general market and home garden sorts, and varieties adapted for arduous conditions such as hot and dry summers or very short growing seasons.
The tomato is largely but not wholly self pollinated and pollen is not carried far. Thus, it is not difficult to breed to practically a pure-line condition.
Tomatoes for seed are usually ground up and the seed and fine pulp are separated from the skins and coarse material by screening. The juice, fine pulp and seeds are allowed to ferment from 24 to 48 hours, or until the jelly-like pulp is readily washed away. After washing, the seed is dried in thin layers and stored. A bushel of tomatoes may be expected to yield 2½ to 4 ounces of seed and an acre of tomatoes, from 100 to 225 pounds. These vary greatly according to varieties and conditions.
Wellington[13]and others have shown that first generation seed from crosses of suitable varieties show a marked increase of vigor (heterosis or hybrid vigor) over either parent or over the later generations. This fact would seem to offer possibilitiesin practical use, but it has not thus far proved of value.
Many growers find it profitable to save their own tomato seed. The plant is an annual, the important characters are quite readily observed and natural crossing is not serious. For these reasons, the enterprise is not as difficult as with most vegetables, although, if done well, it makes heavy demands in labor and care at a time when the grower has much else to do.
The first step in selection is to establish clearly the ideal to be sought, recording it in detail on paper for future reference. Selections should be made on the basis of the plant, not of the individual fruit. It is the plant that is reproduced and the seed from "crown clusters" is no earlier than seed from later settings. The field should be searched soon after blooming time and plants that appear promising should be marked. These plants should be examined three or four times as the season advances, and markers pulled from plants that do not measure up to the desired standard. Suppose ten plants remain; all fruits from each ofthese may be saved, keeping the seed of each plant separate. All or part of the seed may be planted in separate rows the next year for further selection and to note which parents best transmit their excellent points. If only a small amount of seed is required, direct selections may be made for use in planting for the general crop. If a larger amount of seed is required, seed from one or two of the best plants should be planted in multiplication plats. Off-type plants should be removed from such plantings, but otherwise all the seed may be saved for use. Repeated selection results in constant improvement until the stock becomes a "pure line" or practically so.
Lindstrom of Iowa has led in research on the genetics of tomatoes, chromosome relations and mode of inheritance. Many scientific papers deal with inheritance methods and results. The Yearbook of Agriculture (U.S.D.A.) for 1937 contains a valuable chapter on tomato breeding. It may also be had as Yearbook Separate 1581.
As with certain other kinds of seeds, certification service for tomatoes has now been set up inseveral states. Certification is a most useful incentive toward care in breeding and handling and affords valuable assurance to the buyer. It is necessary to know just what is guaranteed by the certificate. It is at the same time wise to be informed as to the inclusiveness and methods of the certification.
In breeding for better varieties of tomatoes, the following are some of the characters to be sought:
(1) A vigorous vine which is necessary to produce abundant fruit and to protect from sunscald.(2) Resistance to disease especially to fusarium.(3) High productiveness with moderate number of fruits per cluster—say,5 to 8.
(1) A vigorous vine which is necessary to produce abundant fruit and to protect from sunscald.
(2) Resistance to disease especially to fusarium.
(3) High productiveness with moderate number of fruits per cluster—say,5 to 8.
Figure 7.—Types of tomato interiors. 1, 5. Small fruited sorts. 2, 6, 9. Bonny Best. 3, 7, 10. Chalk Jewel. 3, 7, 11. Stone. 4, 8. Earliana. 12. Ponderosa.Figure 7.—Types of tomato interiors. 1, 5. Small fruited sorts. 2, 6, 9. Bonny Best. 3, 7, 10. Chalk Jewel. 3, 7, 11. Stone. 4, 8. Earliana. 12. Ponderosa.
(4) Evenness of maturity. This is somewhat out of line with the nature of the tomato but much could be accomplished toward the goal of varieties that make their crop and are gone, eliminating long picking periods and the drag of inferior fruit toward the end of the season. The so-called determinatehabit of some varieties such as Pritchard is a step in this direction.(5) Size suitable for expected use and for market demand. Greenhouse tomatoes are generally smaller than those for cannery. Uniformity of size is increasingly important with wide-spread use of the lug-box pack and of small consumer cartons.(6) Globular to oblong shape is desirable for market but is less important for cannery. Form should be symmetrical, even and smooth.(7) Color should be deep and rich, fully and evenly developed, inside and out. Red is generally preferred to pink. The difference between red and pink tomatoes does not reside in the flesh but in the presence of yellow pigment in the skin of the former while the skin of the latter is without pigment. Yellow tomatoes are alsoextant.
(4) Evenness of maturity. This is somewhat out of line with the nature of the tomato but much could be accomplished toward the goal of varieties that make their crop and are gone, eliminating long picking periods and the drag of inferior fruit toward the end of the season. The so-called determinatehabit of some varieties such as Pritchard is a step in this direction.
(5) Size suitable for expected use and for market demand. Greenhouse tomatoes are generally smaller than those for cannery. Uniformity of size is increasingly important with wide-spread use of the lug-box pack and of small consumer cartons.
(6) Globular to oblong shape is desirable for market but is less important for cannery. Form should be symmetrical, even and smooth.
(7) Color should be deep and rich, fully and evenly developed, inside and out. Red is generally preferred to pink. The difference between red and pink tomatoes does not reside in the flesh but in the presence of yellow pigment in the skin of the former while the skin of the latter is without pigment. Yellow tomatoes are alsoextant.
Figure 8.—The Earliana tomato. A picture of a single fruit cannot adequately describe a variety. 1-3. Rough types, common in older strains. 4. Typical interior. 5, 6. Stem end. 7-9. Good type resulting from selection. 10-12. Pointed-round type occurring frequently in improved strains. A. Unusually large cluster. B. Typical Earliana cluster showing compound branching. C. Unbranched cluster of Bonny Best for comparison.Figure 8.—he Earliana tomato. A picture of a single fruit cannot adequately describe a variety. 1-3. Rough types, common in older strains. 4. Typical interior. 5, 6. Stem end. 7-9. Good type resulting from selection. 10-12. Pointed-round type occurring frequently in improved strains. A. Unusually large cluster. B. Typical Earliana cluster showing compound branching. C. Unbranched cluster of Bonny Best for comparison.
Figure 8.—The Earliana tomato. A picture of a single fruit cannot adequately describe a variety. 1-3. Rough types, common in older strains. 4. Typical interior. 5, 6. Stem end. 7-9. Good type resulting from selection. 10-12. Pointed-round type occurring frequently in improved strains. A. Unusually large cluster. B. Typical Earliana cluster showing compound branching. C. Unbranched cluster of Bonny Best for comparison.Figure 8.—he Earliana tomato. A picture of a single fruit cannot adequately describe a variety. 1-3. Rough types, common in older strains. 4. Typical interior. 5, 6. Stem end. 7-9. Good type resulting from selection. 10-12. Pointed-round type occurring frequently in improved strains. A. Unusually large cluster. B. Typical Earliana cluster showing compound branching. C. Unbranched cluster of Bonny Best for comparison.
(8) Skin should be thick and tough. This safeguards against damage on the way to market and favors ease of peeling. Those saladists who serve sliced tomatoes with skins unremoved, may call for a thin, tenderskin but this practice finds no encouragement from discriminating partakers.(9) Flesh should be abundant in thick walls with a minimum of watery pulp surrounding seeds. In general, a structure of many small cells is desirable.
(8) Skin should be thick and tough. This safeguards against damage on the way to market and favors ease of peeling. Those saladists who serve sliced tomatoes with skins unremoved, may call for a thin, tenderskin but this practice finds no encouragement from discriminating partakers.
(9) Flesh should be abundant in thick walls with a minimum of watery pulp surrounding seeds. In general, a structure of many small cells is desirable.
Earliana.—The earliness of this old and popular variety outweighs its demerits where this character is required. The past ten years have seen material improvement.
Earliana is early, of small vine, with small leaves and leaflets. Clusters are compoundly branched, with many fruits. The fruits are of medium size, deep oblate, cross section often elliptical rather than circular. There are many rough irregular fruits, varying in this respect with breeding and conditions of growth. Color is red, not too deep and tending to be poorly developed at the stem end. Interior consists of many small cells with thin walls.
Bison.—represents a group of varieties bred for rigorous climates of our most northerly states. A. F. Yeager formerly of North Dakota, later ofMichigan, now of New Hampshire has led in this development.
Victor.—is a new variety bred originally by Yeager but introduced by K. C. Barrons of Michigan. It affords smoother, deeper and better colored fruits about as early as Earliana. It is determinate in habit and shy in foliage, increasing danger of sunscald. Rich soil and ample moisture are needed for its best development.BountyandHome Gardenare similar.
Penn State.—Penn State, developed by C. E. Myers of Pennsylvania, is not as early as Earliana. It is similar in fruit characters though distinctly better in color and shape. It is marked by short branches (determinate habit) and is designed to give an early crop to be followed by prompt abandonment of the planting. It is not to be confused with Penn State Earliana.
Bonny Group.—This group embraces our leading second early varieties widely used for home garden, greenhouse, market and cannery in the north. It includesBonny Best,John BaerandChalk Jewelwith many additional names and with much confusion of characters among them.
Bonny Best is second early and of medium plant growth. Fruits are deep oblate to flattened globe,even and smooth, of good red color, with few large, thick-walled cells.
Varieties and strains of this group vary in growth and yield, in size, shape and earliness of fruit and in suitability for greenhouse, market, cannery and juice.StokesdaleandScarlet Dawnare meritorious newer names in thegroup.
Figure 9.—Marglobe plant.Figure 9.—Marglobe plant.
Marglobe.—This variety was developed by the late Dr. F. J. Pritchard from a cross between Marvel, a French variety lending resistance to fusarium and Globe, an old variety of fine size andshape. It is widely used, north and south, for market—green or ripe, for cannery and to some extent, forforcing.
Figure 10.—Marglobe fruit.Figure 10.—Marglobe fruit.
Marglobe is a midseason variety, with large vine and foliage, resistant to fusarium and nailhead spot. Fruits are nearly globular, shapely and smooth, medium to large, scarlet red, with medium number of thick walled cells. Marglobe is rather subject to deep radial cracks.
Pritchardis of the general type of Marglobe but is earlier, with short branching habit and resistance to nailhead rust and to fusarium, and, perhaps, is less subject to cracking.
Greater Baltimoreis used chiefly for canning in long-season districts. It is late, with large vine, large flat fruits of excellent scarlet red, outside and in, with many thick walled cells.Indiana Baltimoreis a variant widely grown in the mid-west for cannery.
Rutgerswas developed by L. G. Schermerhorn at the New Jersey Experiment Station for fine juice and canning characters—color, flavor and substance. Growth is vigorous and yields are heavy; fruits are large, flattened and well colored.
Gulf State Marketis a second early shipping tomato, generally harvested green. It is flattened in shape, of well developed pink color and good interior.
Comet Group.—These trace mostly to English or other European origin and are increasingly used for greenhouse and for staking out-of-doors. Comet is small, flattened, slightly corrugated about the stem, of fine even red color, very firm and solid, with few very thick walled cells. Other names areSunrise, andLord Roberts. SeveralAmerican forcing strains have been developed with at least one parent of this group—Ideal,Grand Rapids Forcing,Field Station Comet,Trellis,Michigan State Forcing,Lloyd Forcing,Blair Forcingand others.
King HumbertandSan Marzanorepresent the small Italian oblong tomatoes that are prized for their thick walls, fine color and suitability for puree, paste and soup.
Ponderosais popular for home garden, a "beef-steak" tomato of very large size, irregular shape, flat, pink, with many small cells and of very mild sub-acid flavor. It is best grown to single stem.Oxheartis large, heart shaped, pink and very meaty. Others of this general type may be had in red, yellow and orange flesh. In general, the whole group lacks in prolificacy.
Oddities.—Tomato fanciers often plant seed of Red and Yellow Pear, Cherry, Currant, Peach with its fuzzy skin, Plum and others. They are prized for preserves and for decoration. Ground Cherry or Husk Tomato is not a true tomato but belongs to a different genus (Physalis). It makes excellent preserves. Well do I remember sneaking off from the other kids for solitary plunder ofthe little row that was usually in Grandma's garden.
Comprehensive descriptions of leading varieties of tomatoes have been published by the United States Department of Agriculture in Miscellaneous Publication 160, the result of statistical and verbal notations over several years at five widely scattered stations of the country.
One of the ways to make money from tomatoes is to mature them early, selling while the price is still high. There is a big difference between $.10 a pound and $.10 a basket. Shipped and ripened green wrap tomatoes cannot be very cheap on northern markets even though Southern growers may realize little for them.
Another way to profit is to grow good plants to sell. Judging by the spindling, crowded, soft or over-hardened plants so common in stores, there should be great opportunity here and, as a matter of fact, many market gardeners do well in this business realizing welcome returns when other income is negligible.
To market ten-cent-a-pound tomatoes from out-doors requires good plants—plants that have passed through their youth nearly or fully up to blossoming time with benefit of heat and shelter and that are ready to keep up vigorous growth inface of the demands of fruiting. A few scattering fruits matured early do not suffice.
Even for cannery, good plants are required. In most regions, plants are not as good as they should be. All too often, outdoor seed bed plants are set where cold frame or at least cloth cover should be employed. Further north, cold frame plants or second run or other inferior plants are used instead of the best. That is why many canning companies have greenhouses and grow plants for their farmers.
And in the home garden, the quality of vine ripened fruit along with the satisfaction of early maturity are goals worth striving for.
Plant growing is a game of skill. It calls for keen observation, constant and faithful attention to small details, and a high order of workmanship in the various operations. Furthermore, when a considerable number of plants are to be grown, it calls for good organization and rapid work if costs are not to be unduly increased. A transplanter who makes three motions where two will suffice is likely to turn profit into loss, for the loss of a second when repeated thousands of times makes many hours.
The grower who is producing tomatoes for first-earlymaturity wants a plant that will withstand the rigors of transplanting and of inclement weather which may follow, that will start immediately into growth, and that will mature fruit in good quantity at the earliest possible date. This usually means a plant about ten inches tall, with heavy, firm, dark-colored stem (though not over-hardened), a heavy body of dark, healthy foliage, and a cluster of blossoms, with possibly a fruit or two already set. If the buds in the axils of the leaves have begun growth, no harm will be done.
Many growers are doubtful whether it is well to have fruit set on plants when they are transplanted in the field, as they claim that the little tomatoes are often lost and in any case the progress of the plant is retarded. Such plants must be handled with great skill. If they are severely checked when taken to the field, other and less advanced plants may do as well. There is danger in having plants too far advanced, and an unexpected delay in field setting may result in spindling and over-hardening that may prove disastrous. A vigorous and properly hardened plant that is younger will do better under such circumstances. Some growers protect themselves by having plants of more than one sort.
With favorable conditions and careful methods, good plants can be grown in open beds but they must be grown and used where the season is long or be grown in the south and shipped north.
Soil should be free of disease and nematodes, of good physical character, full of humus and nutrients.
Seed may be sowed a week or two after "average date of last killing frost" which may be learned from county agent or weather bureau. Further south planting times are gauged by the time tomatoes are to be set and by experience as to safe or reasonably safe sowing dates. Rows are usually a foot apart, more or less. Good plants call for sowing thinly, 6 to 12 seeds per foot, but several seeds per inch are not unusual. One may expect a million plants per acre with close planting or 40,000 plants per pound of seed.
Many millions of tomato plants are grown in open fields in the south to be sent to home gardeners in small parcels on seedsmen's orders, to besold to commercial growers or to be delivered on contract to canners.
A suitable climate and soil, good seed, freedom from disease and insects and good handling and packing are all required for satisfactory results. In far too many cases, these requirements have been sadly neglected and a good deal of distrust has been engendered. Here, as in buying seed, one must discriminate among good and poor growers. Canners who order in millions can send men south to investigate and supervise with good results.
Georgia now has a certification service for plants that helps greatly to build up and maintain high standards.
Varied programs of plant growing are in vogue in the temperate and cooler regions. A simple cold frame with or without transplanting may be employed. Seedlings may be started in hotbed or greenhouse and then transplanted to cold frames to finish the job. Some sow seed early, transplant once in the greenhouse at 1½ or 2 inches each way and then again to cold frame with wide spacing say, 4 × 4 inches or using pots or dirt bands.
For this method, as much as twelve weeks may be allowed but if space permits, excellent results may be achieved in seven or eight weeks transplanting but once to pots or to 4 × 4 inches inflat or bed.
Figure 11.—A good small greenhouse for plant growing.Figure 11.—A good small greenhouse for plant growing.
For northern climates, greenhouses are practically required. Canneries or other large growers, have wide houses similar to those used for winter maturing crops. A market gardener may have a little house of 10´ × 20´ to 20´ × 60´ or larger as needed. If one does not object to some inconvenience and discomfort, a hotbed may be used—heated with hot water or electricity, or as in yearspast, with fermenting manure. Cold frames may be covered with glass sash as in the case of hotbeds, or cloth may be used. There are also materials consisting of wire cloth filled with cellulose film. Special mats of straw or of quilted burlap may be used for extra cover and large growers often employ coarse manure, straw or marsh hay.
Many a tomato gets its start in life in a small flat in a kitchen window—perhaps, in a cigar box. Such seedlings may then be carried forward in hot bed or cold frame.
Growing plants directly in ground beds in the greenhouse and directly in the soil in the hotbeds or cold frames, is rather common. However, the use of flats or plant boxes in plant growing offers a number of advantages as compared with planting in the bed. Transplanting can be done at benches under conditions of comfort and convenience which make for efficiency. Moisture can be more precisely controlled and flats can be shifted if some plants grow faster than others. Plants can be moved with more dirt on the roots, and this is a great advantage when plants are sold and hauledsome distance, though, of course, pulled plants are handled more cheaply. On the other hand, the first cost, and the maintenance and storage of the flats must be considered. Flats may be set on the ground in the greenhouse without use of benches.
Flats are of many dimensions, ordinarily six to ten per sash or about 18 × 22 inches or 13 × 18 inches outside measure. They may be made of lumber from used boxes, but they ought to be uniform in size and made to fit beds without loss of space. The more durable kinds of wood, cypress or chestnut are preferred. Some growers make the bottoms of the flats of square-mesh galvanized screen (hardware cloth), about five or six meshes to the inch. This allows roots to penetrate the soil of the beds, permits root pruning by shifting, and there is no wooden bottom to rot.
Some growers use clay pots for plants which are receiving special care. Their cost is an obstacle though they are used repeatedly. Such pots also hold less soil for the area occupied than flats or squaredirt bands.
Figure 12.—Plants for the early crop. 1. Shows plants in paper bands of excellent proportion and thrift but not yet in bloom. 2. In blossom but fruit has not yet set. 3. Similar to 2 but a little further advanced and has actually set fruit.Figure 12.—Plants for the early crop. 1. Shows plants in paper bands of excellent proportion and thrift but not yet in bloom. 2. In blossom but fruit has not yet set. 3. Similar to 2 but a little further advanced and has actually set fruit.
Paper pots are used to some extent. Organisms decomposing the paper may use and so render unavailable some of the nitrogen of the soil thus hindering the growth of the plants. This may becorrected by seeing that abundant nitrogen is present in the soil either when made up or by later application of nitrate sowed upon the soil while plants are dry or applied in solution in watering.
Dirt bands of veneer are used and are very satisfactory. Blocking as practiced by many growers is a cheap and effective way of attaining much the same results.
When the cold frame is prepared for the last transplanting, two inches of fairly well-rotted manure is laid down and two or three inches of prepared soil is placed on top. Plants are set about four inches apart each way. About a week before field setting, a butcher knife, or a hoe which has been straightened and sharpened, is run between rows both ways. This cuts the roots whereupon the plant at once begins to form new feeders within the block thus reducing, to some extent at least, the damage which might be caused by transplanting. The method is also used with flats.
Soil for plant growing should be free of disease and nematodes, friable, not readily forming a crust, receiving and retaining moisture well, but drying off quickly on the surface after watering and well supplied with nutrients. A sandy loam base with good humus content is desirable. It may be prepared, beginning a year or two ahead by growing and plowing under well fertilized green manure crops. Or a compost heap may be prepared with successive layers of soil and manure or other humus making material. In either case, it is usually mixed a time or two by shoveling over or by passing through a shredding machine or a coarse screen.
If trouble is likely to be experienced from damping-off fungi, the soil may be heated to 200° F. and held there for an hour, using oven or electric or steam sterilizer. Seed may also be treated with red copper oxid or semesan.
Tomato seed runs about 125,000 to 150,000 per pound. An ounce of seed is usually dependedupon for plants for an acre. For growing seedlings, seed may be sowed up to 100 or more per foot of row. For a maximum number of strong seedlings from a small amount of seed, thinner sowing is desirable. Rows are usually about two inches apart, and a quarter of an inch is sufficient cover. The seedlings break ground in a week orten days.
Figure 13.—Tin canFigure 13.—Tin can prepared for sowing tomato seed.
Uniformity of depth of rows and of covering is important. Otherwise, seedlings will come up unevenly and there will be considerable waste.
Water and heat should be provided to permit a steady and moderate rate of growth in plants. Over-watering and high temperature yield soft and spindling plants and also plants that are overgrown and that are liable to severe checking before field setting. Under-watering and low temperature give stunted plants. The thermometer at the earlier stages of growth may well stand around 70 to 75 degrees by day and 10 degrees lower at night. A reasonable range of temperature and moisture gives opportunity for the skillful grower to forward or retard his plants as seems best. Great care should be exercised to water evenly. It is necessary to watch the plants constantly to detect the slightest variations in growth. The watering may then be modified and even progress insured.
Ventilation finds its chief significance as a means of controlling temperature and humidity, though actual change of air may be a factor.
High soil moisture, high humidity, high temperature, and faulty ventilation, all favor the ravages of the various damping-off fungi mentioned above which cause little plants to rot off near the ground.
The main advantage of transplanting plants before they are set in the field is to give them increased space, or, in other words, to conserve space in greenhouses and frames. Other advantages have been claimed, but in many instances the gains have resulted from more space rather than from the actual shift. Transplanting checks growth through breakage and disturbance of the root system. Loomis[14]finds that "the immediate effect of transplanting is a reduction in the water supply, and the immediate and long-time results are dependent upon the severity and duration of such reduction." Transplanting has little effect upon very young plants and a shift at the age of six or eight weeks checks the plant about as much as two earlier transplantings. The tomato falls in the group of plants that stand transplanting well, roots being rapidly replaced. Transplanting breaks roots and so results in the growth of branches which are shorter than the members of the old system. The new system is accordingly less severely damaged in later transplantings.
To insure efficiency, the work of transplanting merits careful attention. Carelessness as to details means loss through unevenness of plants. For example, if soil is not carefully packed at the edges and corners of the flats, irregular water supply and irregular growth result. If much transplanting is to be done, it pays to divide up the work, as is done in a factory. Have a good place for doing the work—a warm, light, and comfortable room. Tired workers are not efficient. Spotting boards are of service if properly made and correctly used. Soil should always contain just the right degree of moisture to allow holes to stand open. Care must be taken that the workers in setting plants do not double the roots or close the holes at the top leaving the roots dangling in an open space below.
It is said that a good worker will prick out 10,000 plants per day, though everything must be convenient to accomplish this and many growers regard 6,000 plants as a good day's work.
Pruning of tops injures rather than helps the plant, for it destroys leaves which are the machines that make carbohydrates, the principal materialfor growth. Pruning to cure legginess is bad. Proper management of time, temperature and water will provide adequate control and if plants should become leggy, it is better to plant them by laying them down in a trench with a few inches of top above ground than it is to prune them.
Nipping out the growing point with the first cluster of flower buds is sometimes practiced to encourage branching and a heavier yield of early fruit. If this is done, ample space and nutrients must accompany careful management. Otherwise, the plant finds itself with inadequate resources to do a big job.
Tomato plants cannot be made frost proof, but low temperature, reduced moisture supply, partial starvation, and crowding all tend to make plants more resistant to cold, to drying winds, to heat, to mechanical injury such as breakage of leaves and stems, and even to cut-worm attacks. Plants can be hardened appreciably in a short time—say a week. It is now generally accepted that moisture control is more useful than reduced temperature as a means of hardening. Starving and crowding are not desirable methods. Plants can be kept onthe dry side if glass or other water-shedding cover is available.
Great care must be exercised to avoid over-hardening of tomato plants, for in this way a check in growth is incurred from which they recover slowly, and perhaps never fully.
Much study has been given to the changes in plants which underlie the hardening process, and papers by Harvey, Rosa, Loomis, and others should be consulted in thisconnection.
Figure 14.—Plants that have been crowded and overgrown,Figure 14.—Plants that have been crowded and overgrown, probably undernourished and over-hardened. Plants like this are very often set in the field. They are definitely slow in starting growth.
Watts[15]has shown that adverse conditions, especially low temperature and water deficiency prevailing at the time when fruit clusters are barely beginning to form, commonly occasion the development of misshapen fruits.
Faithful spraying or dusting with Bordeaux in the plant bed has proved a useful means of forestalling destructive leaf blights which often devastate whole fields.
The tomato is not especially exacting as to care after it has been set out-of-doors. It will do business if given half a chance. At the same time, much can be done to favor earliness, good yield and high quality.
In general, tomatoes are set in field or garden as soon as danger of frost is reasonably past. Suppose May 1st is average date of last killing frost. Growers would make general plantings from May 18th to 25th though, in rare instances, frost might occur as late as May 28th or 30th. The last week of May is planting time over a vast area of the North. Venturesome souls will set home garden plants as early as May 10th, standing ready to replant if necessary. There is little gain in rushing the season too much, however, for the tomato is not only sensitive to frost but it does not thrive under whatpeople call "raw, mean, chilly weather." Such conditions may also be responsible for misshapen fruits. A grower for local market not infrequently risks a share of his plants before safe setting time in the hope that warm weather may give the crop a good start toward early ripe fruit to sell at high prices.
Delayed planting and use of plants that do not start quickly into vigorous growth is the cause of heavy losses in the north, especially among cannery growers. Better quality and heavier yields are attained if the bulk of the crop matures before cool weather in the fall. In the south, it is necessary to get good plant development and a full set of fruit before hot weather which often destroys the blossoms.
Many forms of plant protectors are on the market—of paper and of other materials. These act as little greenhouses for the individual plant, protecting against frost and promoting growth. Plants may be set out-of-doors a couple of weeks earlier by their use. The most common forms are of translucent paper reinforced by pasted strips ofpaper or by wire. The trick is to devise one that is cheap, that will admit maximum light and that will withstand the weather. For tomatoes, they need to be tall, which makes the problem of wind resistance more serious.
For emergencies, opaque cover, baskets upside down or even newspaper may be used. Many a field has been saved by burying the plants when frost threatened, carefully uncovering when danger is past.
Untrained tomatoes are set at distances from 3½ feet each way to 7 × 7 feet or even more. The extreme width is found on rich irrigated lands in California where plants make tremendous growth. The closer spacings are found on lighter soils where humus, plant food, and moisture are not too abundant. The variety should also be considered. Sixteen square feet per plant is about average.
Check row planting is common, though it is not feasible where transplanters are used. Wider spacing between the rows than between plants is desirable as it permits later cultivation one way and leaves a better passage for pickers with less damageto plants and fruits. Thus, 3½ × 4½ feet might be preferred to 4 × 4 feet.
Rows for single stem, staked and pruned plants may be as close as three feet and plants may be as close as eighteen or even twelve inches, though some growers contend that two feet is close enough.
The essential point in field setting is to pack the soil firmly about the roots, thus establishing maximum contact for moisture absorption. Whatever the method of planting, the aim should be to get the plants from the old home to the new with as little delay and check in growth as possible. For the first-early crop, they should be moved so that "they never know it." With bands, pots or blocking in flats or beds, it is feasible to avoid practically all disturbance of roots.
The tomato will, under ordinary favorable conditions, take hold and grow even if shaken quite free of earth. Plants, however, should be dug loose rather than pulled, to prevent undue breakage of roots.
Plants ought to be watered well some hours before transplanting. Transplanting machines andhand planters of the Masters type give a little shot of water at the root, thus helping to establish contact with the soil. Starter solutions are discussed on page 35. These machines are commonly used for cannery setting and, to some extent, for market tomatoes. Blocked plants can be set pretty fast by hand with much less disturbance of roots. Some manage to set potted or blocked plants by machine, keeping a ball of earth about the roots.
The rows are usually marked out fairly deeply, plants are dropped in fours between rows and it is a very short job to pack soil about the clod of earth in which the plant is growing. Another method is for one worker to make an opening with a spade. A second places the plant in the wedge-like opening and the first steps on the soil to firm it solidly about the roots.
Plants are generally set a little deeper than in the plant bed.
The old idea about cultivation was "the more, the better." More recent experiments notably those by Thompson have shown that little need be done beyond controlling weeds. He found that stirring the soil gave no significant increase inyield over mere scraping sufficient to destroy weeds. It is pretty hard to convince many old time gardeners of this. The value of dust mulch for conservation of moisture has been pretty well discredited by experimental comparisons.
Irrigation is not essential for tomato production in humid climates and is seldom provided except under market garden conditions. Water is occasionally an asset in a dry season and, of course, the grower who waters at such times reaps a harvest in higher prices as well as in increased yield. The advantage of irrigation is especially marked if dry weather retards plant growth and delays maturity of the first of the crop, for the high prices of the early market are involved. Judicious irrigation will sometimes continue production for late fall market. Yet gardeners seldom plan permanent overhead equipment for tomatoes. The movable lines that are now used to a considerable extent serve well for the tomato crop.
The furrow method of irrigating tomatoes is the most common in the West. This plan allows the water to make its way down the rows, slowly soakingin all along the line. The tomato stands drouth better than many of our crops, especially if the soil holds moisture fairly well, either naturally or through a liberal humus content. Excessive moisture is doubtless a factor in causing the plants to run to vine and drop their blossoms. Hence, in western sections, it is customary to water thoroughly just before or just after setting the plants and then to avoid applications until the setting of fruit is well advanced.
Thorough soaking is better than frequent light waterings, as it encourages a better development of root system. An Idaho bulletin suggests three irrigations. Late irrigations tend to delay ripening of fruit, but this object is sought in the late fall shipping districts of California which find their best markets after eastern crops have been nipped by frost.
Irrigation must be handled with care to avoid cracking of fruit, which occurs when soil becomes rather dry and then is heavily watered. Watering late in the season is said to make fruit watery and of poor quality.
R. A. Emerson[16]in 1903 reported results of careful comparisons between vegetables that were cultivated and others that were mulched with straw. These results indicate that mulching gives good results with tomatoes, both as to yield and quality. However, frost injury was more severe on mulched plats, and Emerson points out that the mulch should not be applied until the plants are well established.
Mulching is recommended by a good many writers and growers and it seems to be practiced to some extent in Missouri. The advantages claimed are conservation of moisture and clean, fine quality fruit. L. W. Purdum and Sons of Virginia use 4-5 tons per acre of wheat straw, staking their plants and irrigating. They report unusually heavy returns per acre under these methods. The Missouri people apply as much as sixteen tons per acre, making the cover five or six inches thick. The practice of mulching, however, is not common, and the cost will likely prevent its general use.
Growers attending conventions will often stay up half the night to argue about training and pruning tomatoes and to debate the details of their favorite procedures.
For home garden, the method is strongly commended. Many market gardeners follow the practice and it has gained materially of recent years in New England. Some market reports quote staked tomatoes separately and at a materially higher level than fruit from unpruned plants.
Most of the southern shipping sections follow the practice and it is practically universal in greenhouses.
One way is to drive a stake by each plant tying at several points along the stem with cheap twine. The other plan, recently gaining in favor, is to set posts every 25 feet or so, string a heavy wire on top, and another a foot from the ground. Cheap jute twine is strung between wires and the tomato plants are merely twisted around the string. Tyingis not required. Some omit the lower wire, tying a non-slipping bowline loop around the plant near the ground. In either case, plants are kept trimmed to a single stem though occasionally an extra branch is allowed to grow. In southern Illinois, plants are tied to a short stakewithout pruning.