Tomato Solanaceae, Solanum
Place of origin: South America〜Andes region
Characteristics Scientific name: Solanum lycopersicum
Tomato plants like a warm climate, but tomatoes do not tolerate the heat of midsummer in flat, warm places very well. Tomato plants need a lot of sunshine. However, the color of fruit becomes bad in the direct, strong sunshine during the summer time.
Tomato plants are also vulnerable to excessive moisture and the best soil for growing tomatoes is well-ventilated, well-drained soil. However, by watering, the range of soil adaptability can be enhanced from sands to clayey soil. Sandy soils are good for early maturing, while heavy clay soils are good for high yields. Furthermore, the term fruit tomato is not a name for some particular variety, but a collective term describing tomatoes with a high fruit sugar content.
As tomatoes are shade-loving plants, seeds germinate rather easily without light.
When sowing seeds in seed trays, the space between each set of planting rows is 2-3.5” (6-9 centimeters), and the distance between seeds is about 1” (2 centimeters). Cover seeds with the soil, and after giving sufficient water to the seeds, put fine compost over them to reduce drying of the soil, preventing the soil temperature from going down, and don’t give water to seeds until seeds germinate. To prevent seedlings from growing spindly, the daytime temperature of the seed bed should be around 72-770F (22-25℃) and the night-time temperature should be around 60-650F (15-18℃) after germination.
In a case of direct planting, when the temperature is more than 550F (13℃), seeds germinate in 7-10 days. Sow several seeds on one location. Later, thin out seedlings according to the growth of seedlings or cut seedlings near the surface of the soil.
Sow seeds one by one in a seed tray.
In artificial environments it is important not to raise the temperature too high.
When 2-2.5 leaves come out after the cotyledon, transplant seedlings to pots. Give sufficient water to seedlings, and keep the temperature around 770F (25℃) in the daytime and keep the temperature of 600F (15℃) during the night. At a later stage of raising seedlings, lower the temperature to 50-540F (10-12℃) during the night. (After seedlings take root, lower the temperature gradually.)
※ The reason why the temperature needs to be lowered during raising seedlings
If seedlings of tomato are grown in the high temperatures, the differentiation and development of floral buds are promoted early; however, the floral buds are few and weak. Also, the quality of the seedling becomes bad. In lower temperatures, flowers are formed at lower positions, the number of flowers increases, and flowers grow large. (However, seedlings grow slowly.) Therefore, raising seedlings in lower temperatures is better.
As the time of the final planting approaches, expose seedlings to the outside for acclimation. If leaves overlap, give more spaces between pots to prevent seedlings from growing spindly.
Severe drying and low temperatures during the time of raising seedlings greatly affect the growth of seedlings, the yield and the quality of fruit. Therefore, steady management for raising seedlings is crucial.
When the average temperature becomes more than 600F (15℃) and there is no longer any danger of late frost, plant seedlings permanently.
Planting seedlings in a row: The width of ridge is 40-80” (100-120 centimeters) and the space between seedlings is about 30-20” (40-50 centimeters).
Planting seedlings in two rows: The width of ridge is 60-70” 1(50-180 centimeters) and the space between seedlings is about 15-20” (40-50 centimeters).
When 60-65 days are past after germination and the first flower begins to bloom, plant seedlings permanently. It is said that the balance of rooting and blossoming or bearing is good for planting seedlings permanently around this time. Even so, change the planting time according to the size of pot or conditions of the seedlings. (The proper time for planting seedlings permanently is when 4-8 leaves come out after the cotyledon.)
If you plant the seedlings that don’t grow well, they grow becoming yellow and do not root very well. To promote rooting from stems, obliquely plant the seedlings that don’t grow well or the spindly seedlings.
In poorly drained soils, make high ridges. When planting seedlings permanently, if water is secured by rain, watering is not needed. It is absolutely important to check the soil’s moisture level. In order to minimize root damage, when transplanting seedlings, water the pots generously. Take out seedlings carefully from pots not to damage roots. Put seedlings in planting holes on a ridge and gather the soil around seedlings so that the base of the seedling is a little bit higher.
After rooting, new leaves and axillary buds grow, and fertilized ovaries of flowers begin to enlarge, so build support poles early. When the 4th or the 5th fruit grows and enlarges, the fruit becomes quite heavy. If grown outside, as plants are exposed to wind and rain, it is crucial to build support poles firmly to prevent plants from falling over.
In order not to damage stems, work on supports should be done in the afternoon when the stems hold a small amount of water.
After support poles are built, tie a pole and a plant with hemp string under the first inflorescence. By tying a pole and a plant loosely with making a figure of 8, a string doesn’t dig into a stem even when a stem enlarges. By doing this in the afternoon when the stem water reduces, damage to the stems and leaves also can be reduced.
When a plant grows high and reaches the height of a support pole, uncord the hemp string, and try to direct the plant again towards the next support pole by pulling a whole stem as if the lower part of a stem creeps on the ground. Instead of building support poles for each plant, there is another way. Build poles at either end of a row of plants, putting up wires and hanging string on the wires.
To prevent the soil from drying and become too hot, cover the ground with grasses before or after the rainy season.
When the clusters you aim to harvest come into flower and bear fruit, except the two leaves above the last flower cluster, pinch out the tomato plant top. However, it isn’t necessary to pinch out a cherry tomato plant’s top because the cherry tomato plant is hardy, and the harvest period is long when compared to ordinary tomato plants.
Removing side shoots
(Some types of tomatoes don’t need this process.)
Remove side shoots by pinching them out with the fingers. Side shoots should be removed in the morning on a fine day so that cut edge can soon dry, which prevents plants from contracting bacterial disease. If removing side shoots is delayed, side shoots grow large and hard, and need to be cut with scissors. As the liquid from cut edges attaches to scissor blades, if the scissors are used for diseased plants, diseases may spread. Therefore, it is important to remove side shoots when they can be easily pinched off.
As thickly growing and overlapping leaves prevent sunlight or wind from coming through plants, such leaves need to be removed. However, removing leaves just before harvesting badly affects the growth of fruit. If leaf overlap is extreme, cut the tips of leaves by hand and don’t remove whole leaves. During the harvesting time, remove lower dead leaves when you harvest fruit.
The proper temperature in the day time is 20-26℃. With temperatures over 860F (30℃), the fruit doesn’t grow well, and with temperatures over 950F (35℃), flower abscission occurs. Even though tomato plants can grow well in low temperatures, with temperatures below 410F (5℃), plants hardly grow.
If you want fruits to grow uniformly large, leave 4-5 fruits in each cluster and remove malformed fruit or extra fruit. Fruit thinning after fruit grows large has no effect, so it is better to thin the fruits before they grow over 1” (3 centimeters).
According to varieties, length of life and color of ripened fruit are different, but as a whole, except during the highest summer temperatures, wait for harvesting until fruit ripens to some extent. During the heat of summer, harvest fruits that begins to change colors.