4. Sow 10 to 11 weeks before field planting, and make at least three shifts in flats, beds or preferably pots, the space or the size of the pots being increased each time until the plants stand 7 to 10 inches apart. When this method is followed, the crown cluster of flowering buds should be removed as soon as it appears. This will cause the axillary buds and branches to develop rapidly and each to produce a cluster of flowers. The plant will thus have two to five flower clusters instead of one when set in the field. There should be a bountiful supply of ripe tomatoes in 40 or 45 days from the date the plants are set in the field. Ripe tomatoes from plants of this character have been picked in 37 days from the time of planting in the open ground. In many northern markets the tomatoes which are picked soon after July 1 will average about 2 cents each.
Tomato plants should always be grown rather slowly, without check in growth at any time. For a maximum production of first early fruits, each plant should bear two or more clusters of flowers when set in the field.
In many of the southern districts where tomatoes are grown for the cannery, the seed is sown in the open, and the plants set in the field when they are 6 to 8 inches tall. In northern sections plants are generally started under glass or protecting muslin or canvas and set in the field with or without previous transplanting. There is an increasing tendency, however, to transplant at least once before taking to the open ground. Both practical experience and experiments indicate that relatively early sowing with at least one transplanting increases yields. The truckers and market gardeners of the North often exercise almost as much care in starting the late plants as the early ones.
Land manured heavily for a cultivated crop the preceding year should be in prime condition for tomatoes. Heavy clover sods are regarded excellent, especially for the late crop. Green manures are employed extensively in some sections preparatory to planting tomatoes. Whatever the previous treatment of the land has been, early spring plowing and frequent and thorough subsequent harrowing are essential to the best results.
As soils and methods of soil treatment vary greatly on different farms where tomatoes are grown, it is useless to attempt much more than a general discussion of this subject. There is an antiquated idea that the tomato should not be planted in rich soils. This wrong conception of the needs of the plant has perhaps had its origin in improper methods rather than in actual tests of liberal and intelligent feeding. Every observing grower is familiar with the injurious effects of large amounts of soluble nitrogen, applied late in the season, or of fresh stable manures used shortly before planting. Such treatments, especially if there is a shortage of the mineral elements, invariably result in a heavy growth of vine and foliage and a light crop of small fruits. While nitrogen is essential, it should be used in moderation. Its value is greatest early in the season, before the organic forms have had time to be changed by nitrification into nitrates. Numerous experiments show the value of spring applications of nitrate for this crop. Such treatment encourages a vigorous vine growth before the fruits begin to color and in most instances has been the means of increasing the yield. Notwithstanding the beneficial results arising from the use of nitrate of soda, it is admitted that part of the nitrogen should be derived from an organic form, as dried blood, tankage and fish scrap. For the late crop the soluble forms of nitrogen are not so useful, and yet in thin soils they may be employed to advantage.
The mineral elements must also be supplied in ample quantities, for without them the fruits will be small and inferior and the crop light. There should be a proper proportion of the three elements applied. This will doubtless vary greatly in different soils, or even on the same type, the amount of each to use depending upon previous methods of cropping and of soil treatment.
A knowledge of the composition of the fruit and the vines assists in the determination of a satisfactory combination of fertilizing ingredients. Voorhees ("Fertilizers," p. 233) estimates a ton of the fruit and vines to contain the following amounts of nitrogen, phosphoric acid and potash:
Composition of Tomatoes
Phosphoric acid lbs.
In fruit ...............
Vines (green) .......................
He estimates that a yield of 10 tons an acre, with vines of probably four tons, would contain 57 pounds of nitrogen, 16 of phosphoric acid and 94 of potash.
Because the requirements of soils vary widely, Corbett (Farmers' Bulletin, 220, U. S. D. A., p. 11) recommends the following simple fertilizer test:
Plot 1. Nitrate of soda, « pound to 10 plants. Plot 2. Muriate of potash, « pound to 10 plants. Plot 3. Phosphate, 2 pounds to 10 plants. Plot 4. Nitrate of soda, « pound; muriate of potash, « pound to 10 plants. Plot 5. Phosphate, 2 pounds; muriate of potash, « pound to 10 plants. Plot 6. Nitrate of soda, « pound; phosphate, 2 pounds to 10 plants. Rot 7. Nitrate of soda, « pound; phosphate, 2 pounds; muriate of potash, « pound to 10 plants. Plot 8. Barnyard manure, I shovelful to the plant. Plot 9. Unfertilized. A careful record should be kept of the fruits from each plot.
On thin soils rotten manure is often used. It increases the size and the yield of the fruit. It is frequently applied in hills or furrows.
The most successful growers of early tomatoes use fertilizers carrying about 4 per cent nitrogen and 8 to 12 per cent each of the mineral elements. Amounts vary from 500 to 1,000 pounds an acre. In good soils the percentage of nitrogen may be reduced to 2 per cent. A smaller proportion of nitrogen is generally an advantage for the late crop.
Tomato plants should be set in the open ground with as little check in growth as possible. If properly grown and hardened, there should be practically no wilting or checking of growth when the transfer is made. Nothing is gained by exposing the plants to cool, frosty nights, for under such conditions they make very little growth, and there is a great risk of serious loss from hard frosts. The plants should be hardened as much as possible before setting in the open ground.
The proper planting distances should be determined by the productiveness of the soil, vigor of the variety to be grown and by the method of culture or system of training to be followed. In thin soils and with early varieties 3×3 feet apart will be satisfactory. In many soils 3 to 3« × 4 feet are good distances for early varieties; 4 × 4 and 4×5 feet are common planting distances for late varieties. Even more space is often allowed in soils where a rank growth is secured.
The usual methods of transplanting are employed. In the canning districts transplanting machines are in common use.