Tomato Cultivation Techniques Explained in Detail: Master the Key Points of Planting and Management
Temperature Conditions for Tomato Growth
Tomato is a warm-loving vegetable; generally, a temperature range of 15-35°C is suitable for tomato growth. The optimum temperature for assimilation is 20-30°C. When the temperature reaches as high as 33°C, growth is affected; at 40°C, growth stops; and at 45°C, high-temperature damage occurs. When the temperature drops below 10°C, growth slows, and at 5°C, growth stops. At minus 1-2°C, tomatoes will freeze to death, but seedlings that have been hardened by cold tolerance training can withstand short periods of minus 2°C. The optimum soil temperature for tomato growth is 20-23°C; when the soil temperature drops to 6°C, root growth stops.
Temperature Requirements of Tomatoes at Different Developmental Stages
During the seedling stage, the optimum temperature is 20-25°C during the day and 10-15°C at night. If the temperature during the seedling stage is too high or too low, it easily leads to weak seedling growth, poor flower bud differentiation and development, reduced flower quality, and easy occurrence of flower and fruit drop during the flowering and fruiting stage.
The flowering stage is sensitive to temperature; the optimum air temperature is 20-30°C during the day and 15-20°C at night. When the flowering stage encounters low temperatures or high temperatures above 30°C, pollen grain germination and pollen tube elongation are poor, fertilization is poor, and flower and fruit drop easily occurs.
The optimum temperature for the fruiting stage is 24-26°C during the day and 12-17°C at night.
The optimum temperature for the fruit coloring stage is 20-25°C; above 30°C, coloring is poor.
Tomato growth and development require a certain temperature difference between day and night, especially during the fruiting stage. During the day, tomato plants carry out photosynthesis to produce nutrients; appropriately lowering the temperature at night is beneficial for nutrient transport and accumulation, promoting the growth of roots, stems, leaves and fruits, thereby increasing yield and quality. Therefore, in winter greenhouse tomato production, excessive night heating often leads to excessive vegetative growth and other phenomena.
Suitable Temperature Conditions for Tomatoes at Different Stages
In the early growth stage, the relative air humidity in the greenhouse should be maintained at 60-65%. In the middle and late growth stages, the relative air humidity should be maintained at 45-55%.
What Kind of Light Conditions Do Tomatoes Need for Growth
Tomato is a light-loving short-day crop, but most varieties do not have strict daylight requirements and do not need a specific photoperiod; as long as the temperature is suitable, they can be cultivated year-round. Generally speaking, tomatoes grow well under 16 hours of light; the light saturation point of tomato is 70,000 lux, and normal development requires 30,000-35,000 lux.
The germination stage does not require light;
The seedling stage has relatively strict light requirements; insufficient light delays flower bud differentiation, raises the node position of flowers, reduces the number of flowers, and lowers flower bud quality;
Insufficient light during the flowering stage easily causes flower and fruit drop;
During the fruiting stage under strong light, fruit set is greater and individual fruits are larger; under weak light, the fruit-setting rate is low, individual fruit weight decreases, and hollow fruit and rib rot fruit are also prone to appear.
What Kind of Moisture Conditions Do Tomatoes Need for Growth
The aboveground stems and leaves of tomato are luxuriant, and transpiration is relatively strong; the transpiration coefficient is about 800, so it needs more water. However, the tomato root system is very well developed and has strong water-absorbing capacity, and its water requirement is characterized as semi-drought-tolerant; a relative air humidity of 45-50% is suitable.
At different growth stages, tomatoes have different water requirements.
During the seedling stage, growth is relatively fast; to avoid excessive vegetative growth and disease occurrence, soil moisture should not be too high, and irrigation should be appropriately controlled.
Before the first inflorescence sets fruit, too much soil moisture easily causes excessive vegetative growth of the plant, poor root development, and flower drop.
After the fruit of the first inflorescence expands, the water requirement increases significantly.
During the fruit expansion stage, each tomato plant absorbs 1-2 liters of water per day. According to soil transpiration conditions, water appropriately, with small amounts and frequent watering. During the full fruiting stage, the watering interval is 5-7 days.
Watering Principles
① The tomato root system is very well developed; to control excessive vegetative growth, watering is very important. First, build ridges to prevent flood irrigation, ensure normal crop growth without water shortage, avoid root drowning and death, and avoid stem base rot. The ridge height is generally 22-25 cm, divided into large and small rows. The large row is 80 cm wide, and the small row is 60 cm wide. The small row is formed into a “V” shape. Water once lightly 5-7 days before planting; for a 25 cm high ridge, water to a depth of 18-20 cm. The faster the watering speed, the better; this is called pre-planting irrigation. After 5-7 days, plant the seedlings behind the water level line of the ridge, then water with the planting water to ensure the seedlings are on the same water level line. After another 5-7 days, water with the seedling recovery water. After the soil moisture is good, hoe to increase soil aeration and prevent water evaporation.
② Cover with plastic film in advance to prevent moisture loss. The plastic film must be white; black plastic film will affect root growth. When the temperature is high, after laying the plastic film, do not spread it out; place it along the edge of the small ridge to prevent high temperatures from damaging crop leaves. No watering is needed for 20-25 days. Water and fertilize after the first truss fruit grows to the size of an egg or after the third truss flowers have set fruit. When the seedlings grow to 40 cm high, during the hottest time at noon, press the seedlings to one side and then along the ridge direction to prevent excessive vegetative growth; after the seedlings stand up again, hang them on trellises. The part that was laid on the ground should not be lifted again; it will later produce many adventitious roots, increasing the fruit expansion speed in the later stage and raising yield.
What Kind of Soil Do Tomatoes Need for Growth
Tomatoes do not have very strict soil requirements; it is best to choose deep soil, well-drained, fertile loam rich in organic matter. During the growth period, tomatoes need to absorb large amounts of nutrients from the soil. To produce 5,000 kg of fruit, 33 kg of potassium oxide, 10 kg of nitrogen, and 5 kg of phosphorus need to be absorbed from the soil. Of these elements, 73% are distributed in the fruit, and 27% exist in vegetative organs such as stems, leaves, and roots.
How to Enhance the Light Exposure of Protected Cultivation Tomatoes
Reasonable layout: When transplanting and planting tomatoes, strive for uniform seedling size and tidy plant growth to reduce shading between plants. At the same time, it is better to make beds and plant in a north-south direction so that they receive sunlight as much as possible and avoid mutual shading.
Keep the greenhouse film clean: Water droplets, dust, and other debris on the greenhouse film can reduce light transmittance by about 30%. It is recommended to use drip-free film.
Reasonably uncover and cover straw curtains: On the premise of doing a good job in heat preservation, generally uncover the curtain 0.5-1 hour after the sun comes out, and cover it again half an hour before the sun sets. Especially in rainy weather with intermittent rain, the curtain should also be appropriately uncovered to make full use of scattered sunlight.
Set up reflective screens: Hang a 2 m wide and 3 m long aluminized film reflective screen on the north side inside the greenhouse, perpendicular to the ground. This can increase ground light by about 40% and raise greenhouse temperature by 3°C-4°C. In addition, laying silver-gray plastic film on the ground can also increase the light intensity between plants.
Do a good job in plant training: Timely carry out field management such as pruning, removing side shoots, tying vines, and removing old leaves to facilitate ventilation and light transmission in the greenhouse.
The Role of Various Fertilizer Elements
① Nitrogen fertilizer: Increases the speed of crop nutrient transport, elongates internodes, elongates petioles, and enlarges leaves. It should be used in limited amounts; excessive use causes crop internodes to become longer, stems to become thin, petioles to become overly long, leaves to become oversized and thin, leaf color to become light yellow, flowering to be delayed and fruits to be small, fruit expansion to be slow, yield to be affected, and disease resistance to decline (old greenhouses must use less chicken manure and compound fertilizer). Cold resistance also greatly declines.
② Calcium superphosphate: Contains phosphorus and calcium. Calcium fertilizer increases crop cell division, promotes flower and fruit expansion, makes floral organs robust, improves pollination rate, and reduces deformed fruit. When soil temperature is low, root growth is slow, and it is difficult to absorb calcium, causing calcium deficiency, deformed fruit, and rib rot fruit. The remedy is to apply calcium nitrate by water flushing. When each truss fruit grows to the size of a peanut, spray calcium nitrate once per truss fruit to prevent it.
③ Phosphate fertilizer: Promotes crop root growth and determines the number of roots. Phosphorus deficiency reduces the number of main roots and affects nutrient transport to the crop. When plowing in the early stage, good phosphate fertilizer must be used so that roots go deep, transport nutrients well for the crop, increase cold and drought resistance, reduce the number of waterings, and prevent severe disease caused by excessive watering and high humidity.
④ Potassium fertilizer: When plowing, potassium sulfate should be used to strengthen stalks, expand fruits, make fruit color good, surface bright, hardness good, and transport-resistant.
⑤ Magnesium fertilizer: Increases crop chlorophyll content and promotes photosynthesis. If magnesium fertilizer is insufficient, irregular large yellow spots and chlorosis appear on leaves. The distribution of various trace elements is directly related to magnesium.
⑥ Zinc fertilizer: Speeds up crop nutrient transport, makes growing points grow faster, and they also carry out photosynthesis without yellowing or shrinking heads.
⑦ Iron fertilizer: After being absorbed by crops, it inhibits bacterial growth, forms a protective film on the leaf surface of crops, and improves crop disease resistance. Lack of iron element causes plant leaves to turn yellow and resistance to decline.
⑧ Boron fertilizer: Increases crop cell division, promotes flower bud differentiation, and improves the balance between reproductive growth and vegetative growth of crops. If boron is lacking, flower buds do not form or are small.
⑨ Copper sulfate: Improves crop disease resistance and forms a waxy layer on the surface of crop leaves and stalks, preventing bacteria from invading.
There is a certain amount for the use of various elements; excessive use of each element will affect the absorption of other elements.
How to Fertilize Tomatoes
Apply sufficient base fertilizer: The base fertilizer is mainly decomposed high-quality organic fertilizer, applied at 2,500-3,000 kg per mu, and combined with an appropriate amount of chemical fertilizer according to differences in tomato variety maturity and cultivation period.
● For early-maturing varieties, apply 25-30 kg of calcium superphosphate, 15-20 kg of potassium sulfate, and about 10 kg of urea per mu.
● For late-maturing varieties, nitrogen fertilizer should be controlled more appropriately.
● For the distribution of nitrogen chemical fertilizer in plastic film mulched tomato cultivation, it is generally considered appropriate to split it half as base fertilizer and half as topdressing.
Except for phosphate fertilizer, full-layer fertilization can be implemented so that fertilizer is evenly mixed with the plow layer soil, achieving integration of soil and fertilizer. Calcium superphosphate should be fully mixed with organic fertilizer and then applied in strips in the planting holes to reduce phosphorus fixation by the soil. After tomato seedlings are placed in the planting holes, immediately pour 500 kg of decomposed dilute manure to stabilize the seedlings. In addition, to enable normal tomato root growth and increase sugar content, applying a small amount of boron fertilizer at sowing is very effective.
Reasonable topdressing: 7-10 days after planting, apply one fruit-promoting fertilizer with watering, using 500 kg of dilute manure per mu. When the first truss fruit begins to expand, apply 10-15 kg of urea with watering. When the first truss fruit is nearly harvested and the second and third truss fruits are expanding, the plant enters the peak production period; apply about 1,000 kg of dilute manure per mu or quick-acting nitrogen fertilizer, preferably alternating dilute manure and nitrogen fertilizer, with continuous topdressing 3 times, which can achieve the goals of strengthening seedlings, preventing premature aging, and improving fruit quality. In each topdressing period, combining with 200-300 times diluted Haiseling biological stimulant can play multiple roles such as rooting and strengthening seedlings, balancing nutrition, and preserving flowers and fruits.
Timely foliar fertilization: In the middle and late stages of tomato growth, stem and leaf growth begins to slow. In order to strive for middle and late stage yield and prevent premature aging, foliar spraying of 500-880 times diluted Linkali phosphorus-potassium source has a good effect on promoting fruit development.
How to Scientifically Fertilize Protected Cultivation Tomatoes
Attach importance to organic fertilizer: Organic fertilizer contains comprehensive nutrient elements. Its fertilizer effect is slow and long-lasting. The organic fertilizer used must be well fermented; otherwise, harmful gases are easily produced.
Generally, apply 4,000-5,000 kg of high-quality organic fertilizer per mu. Microbial inoculation preparations can also be applied at 2-3 kg per mu.
Balanced application of chemical fertilizers: Chemical fertilizers have high nutrient content and quick fertilizer effect and can make up for the deficiency of certain nutrient elements in organic fertilizer and soil. As long as they are applied in a balanced way, they will not cause harm to plants and the environment.
Commonly used fertilizers include: urea, calcium superphosphate, potassium sulfate, borax, zinc sulfate, and ternary compound fertilizer, etc.
Topdressing Principles for Protected Cultivation Tomatoes
The general principle is “one control, two promotions, three sprays, four taboos”
One control: During the period from tomato planting to before fruit set, topdressing should be based on seedling condition, and the amount of topdressing should be controlled. Too much and too concentrated topdressing easily causes excessive vegetative growth of plants and even flower and fruit drop. Therefore, when plants are severely deficient in fertilizer, the amount of topdressing should generally be controlled, and only a little dilute manure water or biochemical organic fertilizer liquid may be applied.
Two promotions: During the tomato fruit expansion stage and harvest stage, topdressing should be applied appropriately to promote growth and development. When the first truss fruit grows to the size of a walnut, quickly apply quick-acting fertilizer 1-2 times, generally using 30% human manure urine or 5% sulfur-containing compound fertilizer extract to ensure the plants do not lack fertilizer. After young fruits enter the expansion stage, in order to meet plant growth needs and avoid fertilizer shortage in the later stage, the method of “frequent topdressing and vigorous maintenance” should be adopted, generally applying 40% human manure urine or 5% sulfur-containing compound fertilizer extract once every 10 days on sunny days.
Three sprays: When soil topdressing cannot be carried out during the fruit growth period, foliar fertilizer should be sprayed 2-3 times. Haiseling biological stimulant foliar type can be sprayed at 300-500 times dilution, and Linkali phosphorus-potassium source can also be sprayed at 500 times dilution to improve tomato quality.
Four taboos: First, avoid pruning side shoots, removing leaves, and pinching during wet soil and high noon temperatures; second, avoid overly concentrated fertilization, because concentrated fertilization easily causes excessive vegetative growth and harm; third, avoid fertilizing when the soil is relatively wet, otherwise physiological diseases such as flower drop, leaf drop, and fruit drop easily occur; fourth, avoid fertilizing under high temperature conditions, otherwise the plant leaves lose a large amount of water through evaporation, which will affect the exertion of fertilizer efficiency; applying in the early morning or evening is suitable.
Improve Soil and Prevent Continuous Cropping Problems
Due to years of continuous planting, the soil is prone to continuous cropping problems, affecting yield. Soil improvement can make the land “alive” again, allow crops to grow normally, and achieve the goal of high yield. The key to soil improvement is to cultivate the number of beneficial bacteria in the soil, help decompose fertilizers in the soil, accelerate transformation, and help crops absorb them better.
It is recommended to use Haiseling biological stimulant drenching type, which can effectively loosen soil, improve soil and reduce acidity, increase soil organic matter, and stimulate root development.
Skillfully Dipping Flowers to Improve Tomato Quality and Yield
Flower dipping concentration: Use 2 ml of 2,4-D mixed with 1-1.5 jin of water; use 2 ml of fruit-setting agent mixed with 1.3-1.6 jin of water. The best temperature for flower spotting is 18-26°C.
Flower dipping methods and techniques: There are techniques for dipping tomato flowers, which can improve both tomato yield and quality and can make tomato fruits uniform in size, with several fruits in one truss expanding and coloring at the same time. Adjusting the timing well when dipping flowers plays a key role in the uniformity of tomato fruits.
● When tomatoes bloom, if the first flower of each truss blooms too early, and the later flowers are numerous and sufficient, remove the first flower, and also remove deformed flowers.
● If two flowers bloom at the same time and there is no deformity, they can be kept. Do not dip or spray flowers immediately; wait two days and then spot flowers, and when the later flower buds slightly open, dip or spray flowers together. In this way, the flower buds are stimulated by hormones at the same time and pollinate and expand together at the same time, making the fruits of each truss uniform in size. If the first two opened flowers are spotted in advance, they will quickly seize nutrients, causing the later flowers to delay their flowering time, making the flowering time spread out more greatly and resulting in uneven fruit, and even causing the later flowers to develop into stiff fruit that cannot grow large due to malnutrition.