The pruning or training of tomatoes is not generally practiced, except in greenhouse culture, where single-stem training has met with universal favor. This system is also used to some extent in field and garden culture. The advantages claimed for it are: (1) The bulk of the fruit ripens earlier than under natural methods; (2) there is less trouble from various fungous diseases; (3) the fruit is larger and finer in every particular ; (4) the fruit is clean when picked, thus the expense of preparing for market is reduced; (5) spraying and cultivation may be continued longer because the vines are not lying prostrate on the ground and interfering with these operations; (6) harvesting is more convenient; (7) on account of earlier maturity the land may be used for a second crop of vegetables, or for a cover crop to be used for manurial purposes.
While the results secured by many practical growers and the rather numerous investigations at the experiment stations support the foregoing arguments for this system, some practical growers are opposed to it and some tests at the stations are not favorable. The objection usually raised is, the expense of single-stem training. More plants are required to the acre; stakes must be provided, placed, removed after harvest and stored for the next crop; the axillary buds must be pinched out weekly and the plants tied to the stakes. These operations involve considerable labor and no grower should adopt the system unless he is certain of the required labor.
Single-stem training is practiced most extensively in the vicinity of Marietta, O. Probably 500 acres were staked in that region in the summer of 1910. In one field one often sees 20,000 to 30,000 plants, and at the height of the season, 10 or more cars are shipped in a day, all of the crop having been grown by this method. The pink tomatoesóBeauty, Acme, Globe, and June Pinkó are the most popular varieties at Marietta. The strong, vigorous plants are set in check rows about 4 feet apart and the plants 30 inches apart in the row, 4,000 to 5,000 plants being generally set to the acre. The stakes are from 1 to 1 1/2 inches in diameter and 5 feet long, and are driven in the ground when the plants are set. They are split by hand from oak, since split stakes are stronger and more durable than sawed ones. The average cost of these stakes at Marietta is about I cent each. The plant is tied to the stake as soon as possible after planting. All side buds are nipped as soon as they appear. The plant is nipped when it reaches the top of the stake. It is supported by tying with coarse twine or raffia at four different places.
It is estimated that the average yield in the Marietta region is from 10 to 15 pounds, and that receipts run from 5 to 13 cents a plant. The tomatoes are packed in splint baskets holding 25 to 35 pounds, and shipped in refrigerator cars. Nearly all sales are made through the local association.
Another plan used sometimes, especially when there is a limited area of land available for this crop, is to plant about 2x4 feet apart, drive a strong stake at each plant, and tie up all vines without any pruning. This plan results in a much larger yield to the acre than if this extra work were not done, but the added expense is a very objectionable feature, and the system is seldom used. Various forms of trellises or supports, often used in home gardens, serve to keep the fruit clean and may reduce the percentage of rot.
The proper time of harvesting depends upon various factors, as distance from market, character of the weather and danger of frosts. In the far South, tomatoes are usually picked as soon as they show the slightest change in color. This always results in a sacrifice of quality, because the best flavor is developed when the fruits are permitted to remain on the vine until fully ripe. Even for local markets it is customary to pick the tomatoes before fully ripe, and this is generally necessary in order to have the fruit reach the consumer in solid condition. Tomatoes lose their firmness very rapidly in warm weather, so that it is especially important to guard against this trouble in handling the midsummer crop. When there is danger of destructive autumn frosts the only safe policy is to pick every specimen that shows any change in color. The fruits will continue to ripen in any convenient outbuilding or in the cellar. They also ripen rapidly under hotbed sash or in the greenhouse. Tomatoes should always be handled with the greatest care to avoid bruising.