The Tomato is one of the most popular vegetables grown in the United States. It ranks second only to potatoes in economic value. Its fruit is high in food value, vitamins and minerals and is served raw in salads, baked, stewed, fried and made into soup, conserves, pickles, catsup and a variety of sauces.
The Tomato is native to Central and South America. While its culture is ancient it has only reached its present prominence since the mid-19th century.
Tomato Types and Varieties
Most authorities recognize 2 distinct species, L. esculentum which includes the common, potato-leaved, cherry and pear types and L. pimpinellifolium or the Currant Tomato.
Seed companies list a large number of so-called varieties which may vary in days to maturity, habit of growth, shape and color of fruit and disease resistance. Hybrid sorts are becoming most important. Suggested varieties are ‘Early Hybrid’, ‘Valiant’, ‘Morton Hybrid’, ‘Supersonic Marglobe’, ‘Big Boy’, plus ‘Jubilee’ (orange-yellow fruit) and ‘San Margand’ as one of the best small fruit sorts used for paste. Check seed catalogues for other sorts of excel-lent quality. Many other varieties are available that are good to use in various parts of the country.
Tomato Climatic Requirements
The Tomato is a warm-season plant, frost tender, and most varieties require at least 34 months to produce a full crop. A number of factors may affect fruit set such as faulty nutrition, injury from disease or insects and weather conditions. Temperature is very important in that temperatures below 55° F. and above 95° F. reduce fertilization of the flower. A period of rainy or cloudy weather will have a similar effect. Fruit set of the first and second clusters of plants set out fairly early in the spring can be materially increased by the use of chemicals sprayed onto the flowers. These come under a number of trade names such as “Sureset” and are available at most trade outlets, seed houses or garden centers.
Tomato Soils and Fertilizers
The Tomato will grow in a variety of soils provided such soils are warm, have a high water-holding capacity, contain a readily available supply of plant food and test a pH of 5.5 to 6.5. In general, the loam soils are preferred. Soil preparation resulting in a deep friable condition is important for the development of a strong root system.
Tomatoes will respond to an application of well-rotted manure if it is available. In most cases, it is advisable to apply 30-40 lbs. of a 5-10-10 fertilizer broadcast per 100 sq. ft. just prior to planting. This is then supplemented by side dressings of nitrate of soda, 2-3 oz. per plant, at 2-3-week intervals if the plant grows this weak and lacks vigor. Side dressing is applied in fairly wide bands around the plant and then cultivated into the top 2 in. of soil. In many cases an application of cupful of a starter solution applied at the time the plants are set out in the garden is beneficial.
Tomato Plant Growing
Under most conditions tomato plants are started in greenhouses or hotbeds some 6-8 weeks prior to planting out-of-doors. Plant seeds in flats or boxes where the temperature is approximately 70° F. Use fine, medium-rich soil, sowing seed in drills in. deep and 2 in. apart. When the seedlings are 2 in. high, replant at 2 in. x 2 in. intervals and allow growing until 4-5 in. tall. At this stage the plants should again be replanted to a spacing of 4 in. x 4 in. Plant bands, clay or plastic pots, berry baskets or tin cans can be used for this last transplanting. A day temperature of 70-75° F. and a night temperature of 60-65° F. is ideal. Apply enough water to maintain a moist soil.
Tomato Outdoor Planting
Tomato plants should not be planted out-doors until all danger of frost is past and the soil has become reasonably warm. The spacing will vary because of variety and method of culture. Plants that are not trained or pruned are planted 3 ft. x 3 ft. or 3 ft. x 4 ft. for such varieties as Fireball or Victor and 4 ft. x 4 ft. for the larger plants of the main crop varieties. Where space is a limiting factor it may be advisable to stake or trellis the plants. In each case, all lateral or side shoots are pinched out as they develop so as to restrict the plant to 1 main stem. In staking, a 5-6-ft. stake is driven into the soil 11-2 ft. next to each plant. As the plant develops the stem is loosely tied to the stake with jute twine, twistems or ordinary strips of cloth. In trellis culture a post is placed at each end of the row. A heavy wire is then stretched from the top and bottom of these posts. Jute twine is tied to the bottom and top wires at each plant and the plant is twirled around the string as it develops. Planting distances for staked and trellised plants are 15-18 in. in the row and rows spaced at 3-4 ft. Self-topping or determinate varieties should not be staked.
Normal shallow cultivation is necessary to control weeds. Mulches of various types are also recommended to control weeds and to conserve moisture. Strawy manure free from weed seeds or marsh hay or black plastic is excellent materials.
Top quality is only obtained if the fruits are left on the vine until they are red-ripe but still firm. In the fall if green tomatoes still remain on the plant at frost time, if they are from to fully matured in size they can be picked and stored for up to 3-4 weeks at a temperature of 50° F., a fairly high humidity and preferably in the dark. To ripen stored fruit place on the kitchen window sill at a temperature of 70° F. or higher for from 3-5 days.
Tomato Insect Pests
Cutworms cut stems of transplants. Flea beetles which eat holes in leaves which permit entrance of disease are controlled by sprays or dusts of insecticide usually combined with fungicide. Applications just before transplants are set and 2 or 3 times at weekly intervals are usually necessary. Aphids deform new growth and spread disease. Larger voracious horn worms can be hand-picked or sprayed with insecticide. Tomato fruit worm, which is also the corn ear-worm, eats holes in the fruit. Sprays of insecticide are suggested. European corn borer, stalk borer and Colorado potato beetle are occasional pests. Red spider mite is controlled with insecticide.
Early blight and late blight are most destructive. Early blight starts about the time the first fruits begin to ripen and may cause defoliation. Late blight starts in late summer and infects both fruit and foliage. Sprays or dusts of fungicide at weekly intervals are recommended. Shiny dark spots on both green and ripe fruit indicate anthracnose which is checked by the above fungicides. Fusarium wilt causes yellow and dead leaves on the lower part of the plant and decreases the size and quality of the fruit. No fungicides are effective. Grow resistant varieties where fusarium has occurred. Mosaic-infected plants are weak and un-productive. Destroy infected plants as soon as they are observed and control aphids. Blossom-end rot is not caused by disease. It is produced by uneven water supply and acid soil. Apply ground limestone to give pH 6.0-6.5 acidity and mulch to help maintain adequate moisture. Rolling of older leaves especially on staked tomatoes is due to hot sun and excess transpiration. It is not controllable except by temporary shading.
Usually they are considered annuals requiring a long, warm, growing season with plenty of moisture to mature properly. The most important species in the U.S. are G. barbadense, the Sea Island Cotton, native to tropical America and growing 8 ft. tall with yellow flowers tinged with purple; G. hirsutum, the Upland Cotton also a native of tropical America, 5 ft. tall with white or yellowish flowers tinged pink at maturity, and several varieties and hybrids. Not grown as a garden ornamental.