Part 9

Care of Seedlings

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.

Transplanting

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 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 Young Plants

Pruning of tops injures rather than helps the plant, for it destroys leaves which are the machines that make carbohydrates, the principal material for 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.

Hardening

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 on the 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 this connection.

Watts 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.

GOOD CULTURE FAVORS GOOD RETURNS

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.

Time of Planting

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 what people 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.

Plant Protectors

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 of paper 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.

Spacing

Untrained tomatoes are set at distances from 3-1/2 feet each way to 7 x 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 damage to plants and fruits. Thus, 3-1/2 x 4-1/2 feet might be preferred to 4 x 4 feet.