Where can I grow tomatoes outdoors?

Where can you grow tomatoes outdoors? There are many in the south. Let's learn about it together.

Growing tomatoes in the open air

1. Quantitative indicators for high-yield cultivation of tomatoes

Tomatoes' temperature requirements: Tomatoes like warmth, and the suitable temperature during the day is 25℃-28℃, and 16℃-18℃ at night. Below 15℃, tomato seed germination, pollination and fertilization, and tomato turning red are affected; below 10℃, growth is slow, reproductive development is inhibited, stems and leaves stop growing at 5℃, 2℃ are cold damage, and 0℃ is frozen to death. Above 35℃, reproductive development is affected, and above 40℃, physiological disorders and heat death. Adequate light and appropriate temperature difference are conducive to nutrient accumulation and ripening, promote healthy plant development, prevent excessive growth, enhance tomato's disease resistance and stress resistance, and increase yield.

Tomato humidity requirements: The basic principle is that except for germination, emergence, and the seedling slowing period after transplanting, high temperature and humidity are required, high humidity is not required in other periods. Regarding water requirements, except for proper water control before transplanting, during the flowering period, and during the ripening period, sufficient water supply should be ensured in other periods.

Principles of tomato nutrition supply: Tomatoes require a large amount of fertilizer, and sufficient nutrition should be guaranteed at all stages. However, the fertilizer requirements at each growth stage are somewhat different. Nitrogen fertilizers are emphasized in the early stage, potassium fertilizers are emphasized in the later stage, and the demand for phosphorus fertilizers is carried out throughout the growth period. However, the demand for potassium fertilizers must be guaranteed during the entire growth period.

Under the condition of ensuring the normal growth and development of tomatoes, low-temperature training of tomatoes can not only improve the plant's own heat and cold resistance, but also reduce the cost of heating and insulation. Generally speaking, the optimal temperature is required at the turning point and key period of tomato growth, such as germination, emergence, flower bud differentiation, pollination and fertilization, and ripening period, as well as after seedling transplanting, to ensure the appropriate temperature to promote normal reproductive physiological processes and to heal and resume growth as soon as possible after injury; and before seedling transplanting and transplanting, sufficient training is required to ensure that the plant safely passes through the difficult period after injury, and the temperature can be slightly lower during the normal growth stage.

The key to tomato cultivation is to cultivate strong seedlings. The indicators of strong seedlings are 6-7 leaves, 60-70 days old, 20-23 cm high, and 60%-70% visible flower buds.

2. Prepare nutrient soil

Prepare the nutrient soil according to a certain proportion, requiring the porosity of the nutrient soil to be about 60%, pH 6-7, containing more than 100 mg/kg of available phosphorus, more than 100 mg/kg of available potassium, and 150 mg/kg of available nitrogen. It should be loose, retain fertilizer and water, and have complete nutrition. Spread the prepared nutrient soil evenly on the sowing bed (10 cm thick) or in the seedling tray.

3. Seed processing

Tomato seed disinfection. There are two methods: (1) soaking seeds in warm water, which means soaking the seeds in clean water for 1-2 hours, then taking out the seeds and putting them in 55 degrees Celsius hot water, maintaining the water temperature uniformly and soaking for 15 minutes, and then continuing to soak the seeds for 3-4 hours. When soaking seeds in warm water, generally one part seeds and two parts water; stir constantly and quickly to heat the seeds evenly to prevent scalding the seeds; third, hot water should be added continuously to maintain the water temperature of 55 degrees Celsius. This can prevent the occurrence of diseases such as leaf mold, ulcer disease, and early blight. (2) Soaking seeds in trisodium phosphate, which means first soaking the seeds in clean water for 3-4 hours, taking out and draining, and then soaking them in 10% trisodium phosphate solution for 20 minutes, taking out and washing. This method has a relatively obvious effect on tomato virus diseases.

Freeze the potato tubers and then slowly thaw them, then squeeze out the juice. Soak the tomato seeds in the potato juice overnight. The next day, dip a thick, lint-free cloth in the juice and place the soaked seeds loosely on it so that the seeds do not touch each other. Cover them with polyethylene film to prevent them from drying out, but keep them breathable. Then put them in a warm place (do not heat them). After the seeds germinate, insert them into the soil for seedling cultivation. This germination method can make tomatoes mature 2 to 3 weeks earlier than ordinary germinated tomatoes.

4. Germination and sowing

Determine the sowing amount. Generally, tomato seeds contain about 300 seeds per gram. According to the planting density, the seed amount is generally 20-30 grams per 667 square meters of field. 10-15 grams can be sown per square meter of seedbed. If the seed germination rate is less than 85%, the sowing amount should be appropriately increased.

Determine the sowing period. Consider the planting season, climate conditions, cultivation methods, seedling facilities and other factors to determine the appropriate sowing period. For example, in spring open field cultivation, Beijing usually sows and raises seedlings from mid-February to early March. In autumn open field cultivation, the best results are achieved in areas south of the Yangtze River such as Shanghai and Nanjing from late July to early August; while in eastern Sichuan, sowing in early July has a higher yield. The yield is also higher. In some areas where tomato diseases are serious, the sowing period can be appropriately postponed by 1-2 months, and then a higher yield can be obtained through measures such as close planting, early pinching, and increased fertilizer and water.

After the seeds are treated, they can be sown directly, but it is better to germinate them. When germinating, seeds that have not been treated with chemicals need to be soaked in warm water for 6-8 hours to allow the seeds to fully expand, and then placed at a temperature of 25-28 degrees Celsius for 2-3 days. For seeds soaked with chemicals, just rinse the seeds with clean water and then germinate directly. During the germination process, it is necessary to provide suitable temperature, moisture and air. To this end, the seeds should be checked and turned over frequently to keep them in a loose state. They also need to be washed with clean water 1-2 times a day to refresh the air and maintain humidity. It is best to use a constant temperature box for germination. After the seeds are germinated, they will emerge quickly and neatly after sowing, which is conducive to cultivating strong seedlings.

Sowing method. Usually there are broadcast sowing, row sowing and spot sowing. Cover the soil immediately after sowing, and use sieved fine soil for covering. The thickness of the covering soil is about 0.8-1.0 cm, and the thickness should be consistent. After sowing, 8 grams of 50% carbendazim wettable powder per square meter of the seedbed is mixed with fine soil and evenly sprinkled on the bed surface to prevent the occurrence of seedling damping-off disease. In winter and spring, the surface of the seedling bed needs to be covered with mulch. In summer and autumn, the surface of the seedling bed needs to be covered with shade nets or straw, and the covering should be removed when 70% of the seedlings are above the soil.

5. Seedling Management

Generally speaking, if the temperature of the seedling bed is high, the insulation conditions are good, and the seeds are germinated first, they will germinate 2-3 days after sowing. Otherwise, it will take 5 days or longer to germinate.

Seedling management mainly involves the control of temperature and light.

(1) Seedbed management from sowing to emergence. This period refers to the period from sowing to the full expansion of the two cotyledons. The seedling raising period for open-field tomato cultivation in spring is arranged in the cold season in all places, and the bed temperature must be controlled at 25-28 degrees Celsius during the day and 15-18 degrees Celsius at night. When using cold beds or hot beds for seedling raising, full use should be made of solar energy to increase the bed temperature during this period, and covering materials should be used to maintain a high bed temperature. Before emergence, the film is generally not removed and windows are opened for ventilation. When the young buds begin to emerge from the soil, if the cover is too thin and the crust phenomenon is found, the soil should be covered again immediately. The temperature management during the winter and spring seedling raising period is shown in the table below.

(2) Seedbed management from seedling emergence to transplanting. During this period, the main tasks are to adjust the temperature and humidity of the seedbed, and to adjust the timing of seedling thinning and soil covering, improve light conditions, and prevent and control seedling diseases. After the two cotyledons of the seedlings are fully expanded, the bed temperature should be appropriately lowered to 20-25 degrees Celsius during the day and 10-15 degrees Celsius at night to prevent excessive growth. 4-5 days before transplanting, in order to adapt to the lower temperature of the seedling bed, improve the survival rate after transplanting, and promote seedling acclimatization, the bed temperature can be further lowered by 2-3 degrees Celsius. For cold bed seedling cultivation, especially hot bed and greenhouse seedling cultivation, the ventilation holes should be gradually increased during the day to extend the ventilation time. The straw mat or thin mat should also be gradually removed earlier and covered later to extend the light time. Damping-off or damping-off disease, which is easy to occur in the seedling stage, is often caused by not properly ventilating in bad weather, covering the seedbed with straw mats, films, etc. for a long time, and gradually increasing the air humidity in the seedbed. During this period, special attention should be paid to protecting cotyledons; improving light conditions; removing seedlings during harmful periods; water and fertilizer management; and reasonable soil covering.

6. Management during the growth period

Grasp the management during the growth period, including inter-row cultivation and weeding, water storage and moisture conservation, vine rigging and vine binding, pruning and branching, removing old leaves, ventilation and light transmission, strengthening the prevention and control of diseases and pests, and strengthening temperature management. Among them, the diseases of tomatoes are mainly viral diseases, bacterial wilt, early blight, late blight, etc.; the main pests are cotton bollworm, aphids, etc. Tomato diseases can be prevented and difficult to treat, and prevention should be the main focus. The prevention and control methods of viral diseases include: selecting disease-resistant varieties, seed disinfection, planting stubble land, preventing and controlling aphids, and early planting at the right time. Temperature management means that the ventilation volume of the greenhouse should be appropriately increased during the day to keep the temperature in the greenhouse at around 25℃. The temperature at night is maintained between 10-13℃. When starting to ventilate, the vents should be from small to large, from few to many, and the vents should be gradually reduced or closed after the temperature drops in the afternoon.

Pay attention to fertilizer and water management. Tomatoes generally do not need watering during the summer and autumn rainy seasons, but when 2 to 3 bunches of fruits are ripe and there is drought, they should be watered appropriately. According to the growth of tomato plants, topdressing should be done in time to promote fruit development and preserve flowers and fruits. Generally, Jinbaobei microbial fertilizer can be applied as base fertilizer, and Jinbaobei seedling strengthening agent and Jinbaobei sweetening agent can be applied as topdressing to make it look more beautiful and delicious. If conditions permit, cake fertilizers such as bean cake and cottonseed cake can be applied.

7. Fruit picking

Pick the fruits at the right time. There are four stages of ripening of tomatoes: green ripe, color changing, mature, and fully ripe. They can be harvested during the green ripe stage for storage and preservation. They can be picked during the color changing stage (1/3 of the fruit turns red) for transportation and sale. For local sale or self-consumption, they should be picked during the ripening stage, when more than 1/3 of the fruit turns red. When harvesting, they should be picked and placed gently. It is best not to carry the fruit stems when picking to prevent the fruits from stabbing each other during transportation. Before the first frost, if there are still unripe green fruits, they should be picked and stored in the greenhouse. They should be put on the market after the fruits are ripe. This will not only extend the supply period, but also increase economic benefits. It is not advisable to use hormones to stimulate fruit coloring during the ripening period of the fruit. After selection, the fruits should be packed and sold. Its advantage is that it not only reduces production costs and improves fruit quality, but also ensures consumer food safety.

8. Disease and Pest Control

1. Prevention and treatment of tomato flower skin

This is a physiological disease, also called rib rot, stripe rot or stripe rot. It mainly harms fruits. I will introduce it to you below. There are two common types.

The first is the browning type. It starts to occur in the young fruit stage, mainly affecting 1 to 2 bunches of fruit. During the fruit expansion stage, local browning occurs on the fruit surface, the fruit surface is uneven, and some fruits become dark brown and hard or have necrotic spots. When the diseased fruit is cut open, it can be found that the vascular bundles in the peel are dark brown and necrotic, the fruit core becomes hard, or the flesh becomes brown, and the commercial value is lost.

The second is the white variant. It mainly occurs when the green ripe fruit turns red. The symptoms are uneven coloring of the fruit. In mild cases, the shape of the fruit does not change much. In severe cases, green protrusions appear near the fruit stalk, and the red part is slightly sunken. The diseased part has a waxy luster. When the diseased fruit is cut open, the flesh is found to be "heart-shaped" and the vascular tissue of the flesh is dark brown. In mild cases, some vascular bundles turn brown and necrotic, and the browned part does not turn red. The flesh is hardened, the quality is poor, and it tastes bland. In severe cases, the vascular bundles of the flesh are all dark brown, some fruits form cavities, and the bright surface is unevenly red and green. This vegetable farmer is talking about the white variant.

Tomato vein rot is generally not visible on the stems and leaves, but if you cut open the stem 70 cm from the root, you can see that the stem's conductive tissue is brown and has been damaged, causing the above symptoms to appear in the fruit. This is different from viral diseases.

Cause: Since it is a physiological disease, the extent of damage depends on the variety, sunshine hours, light intensity and the ratio of nitrogen, phosphorus and potassium in the soil.

Prevention and control methods: mainly focus on management, increase light appropriately, scientifically determine the sowing and planting period, and use formula fertilization. If the above symptoms have appeared, you can spray multi-element fertilizer.

(1) Physical prevention

High-temperature disinfection of soil: It is carried out during the high temperature period of the three summers. After pulling the seedlings in the protected land in spring, clean the fields first, remove the diseased plants, diseased leaves, and diseased roots from the fields and bury or burn them deeply; apply 50-100 kg of lime and 1,000 kg of broken straw (or wheat straw) per mu, evenly apply them on the surface; deep plow the soil to 66 cm, super high ridges to 33 cm, irrigate, and keep the furrows full of water; lay the ground film and seal the shed for 7-10 days to prevent and control cucumber wilt, blight, root-knot nematodes, etc.

Baking soda or high-fat film to prevent powdery mildew: When powdery mildew just occurs, spray 500 times of baking soda, once every 3 days, for 5-6 times in a row, which can not only prevent powdery mildew, but also decompose carbon dioxide and increase cucumber yield. Or use 80-100 times of 27% high-fat emulsion, spray once every 6 days, for 4 times in a row. (3) Yellow board to attract aphids or silver-gray film to avoid aphids.

(2) Biological control

Disease prevention: For powdery mildew, anthracnose, and black spot, when individual spots first appear, spray 2% agricultural anti-120 or agricultural anti-B0-10 water solution 200 times, spray once every 6-7 days, spray 3-4 times in a row, and can also treat gray mold and downy mildew. In the early stage of bacterial diseases, such as angular leaf spot, spray 100 times of agricultural anti-751 water solution, spray once every 5-6 days, spray 2-3 times in a row.

Pest control: When cucumber aphids occur, you can spray Shaoguanmycin 200 times diluted, add 0.01 neutral laundry detergent, or use 0.65% artemisinin 200 ml, add 60-80 kg of water for spraying. For tea yellow mites, you can spray 20% compound Liuyangmycin 800-1000 times diluted, spray once every 6-7 days, and spray 2-3 times in a row.

(3) Chemical control

For cucumbers in protected areas that have already fallen ill, pesticides with high efficiency and low residual content can be used for proper prevention and control. Downy mildew can be treated with 7% antifungal dust or 80% Dasheng M-45 wettable powder or 72% Lu wettable powder; gray mold can be treated with 5% antifungal dust or 50% antifungal wettable powder or 50% 1000 times dilution of 50% fenfluramide No. 2; angular spot disease can be treated with 5% antibacterial dust or antifungal dust; black spot disease can be treated with anti-black mold dust or 40% Fuxing emulsifiable concentrate; anthracnose can be treated with 8% gram tanling dust or 80% anthracnose fumei wettable powder; aphids and whiteflies can be treated with anti-aphid and anti-lice dust or 10% imidacloprid wettable powder.

2. There is a reason why tomato fruits are hollow

Tomato hollow fruit refers to fruit with a hollow space between the peel and the jelly-like flesh. Although hollow fruit does not have a significant impact on tomato yield, it will seriously affect its commercial quality and reduce economic benefits, and must be taken seriously in production.

Tomato hollow fruit is a physiological disease, and varieties with a small number of ventricles are prone to it. There are many reasons for the formation of tomato hollow fruit, such as improper hormone spraying time, insufficient light, insufficient watering during the peak fruiting period, too many fruits left, insufficient supply of nutrients, etc. In order to avoid the occurrence of hollow fruits, tomato varieties with more ventricles should be selected in cultivation, and regulators should be used reasonably. When 2/3 of the flowers in each inflorescence are open, spray anti-drop agent with a concentration of 15ppm to 25ppm, and be careful not to reuse it. In addition, sufficient basal fertilizer should be applied during cultivation, and formula fertilization technology should be adopted. Topdressing and sufficient watering should be applied in time during the peak fruiting period to meet the plant's nutritional needs. The growth of each tomato variety is different, and the tips should be pinched in time according to the characteristics of each variety to balance the nutritional growth and reproductive growth of the plant.