How to scientifically raise tomato seedlings? Detailed explanation of the technical key points
Seedlings are the foundation of plant development, and good seedlings are the foundation of plant growth. The growth of tomatoes is also inseparable from high-quality seedlings. Tomatoes first exist in the form of seeds. For a tiny tomato seed to become individual tomato plants, it must inevitably go through careful cultivation.
Scientific seedling raising techniques for tomatoes
1. Seed disinfection: To control diseases such as tomato leaf mold, septoria leaf spot, early blight, and bacterial canker, the hot water seed soaking method should be used, that is, place the seeds in hot water at 55°C, stir while soaking for 15 minutes, then soak them in warm water at 30°C for 4-5 hours, remove them, and germinate them at 30°C. To control viral diseases, soak the seeds in a 10% trisodium phosphate solution for 20 minutes, then rinse them clean with water and germinate them.
2. Seedbed soil disinfection: Before sowing, after thoroughly watering the bed soil, spray the seedbed with a 500-600 times dilution of 72.2% Propamocarb aqueous solution, spraying 2-4 kg per sq m. Or disinfect with carbendazim: for every 1000 kg of bed soil, use 25-30 g of 50% carbendazim wettable powder. When treating, first prepare the carbendazim into an aqueous solution, then spray it on the bed soil, mix it evenly, and cover it tightly with plastic film. Generally after 2-3 days, various pathogens such as Fusarium wilt in the soil can be killed.
3. Apply base fertilizer early: When preparing nutrient soil, if sufficient fertilizer is applied, no fertilization is needed throughout the seedling stage. If the seedling leaves are found to become lighter in color and show symptoms of fertilizer deficiency, a small amount of guaranteed-quality potassium dihydrogen phosphate at a 500 times dilution can be sprayed.
4. Proper temperature regulation: After full emergence, the seedbed temperature must not be too high, so that the seedlings grow robustly and their cold resistance and disease resistance are enhanced. During the “two leaves and one heart” stage, the seedbed insulation measures must not fail to keep up. If the temperature remains too low, flower bud differentiation will be blocked, and in early spring flower and fruit drop will be severe, affecting early yield. At noon on sunny days, the seedbed temperature can easily become too high. At this time, do not uncover the covers and ventilate heavily, to prevent the seedlings from wilting or dying due to excessive temperature difference and excessive water loss.
Seedling stage management of tomatoes
Seedling stage management in tomato cultivation is mainly the control of temperature and light.
① Seedbed management from sowing to emergence: This period refers to the period from sowing to the full unfolding of the two cotyledons. For open-field cultivation of tomatoes in spring, the seedling raising period is arranged in the cold season in all regions, and the bed temperature must be controlled at 25-28°C during the day and 15-18°C at night. When using cold beds or hotbeds for seedling raising, full use should be made of solar energy during this period to raise the bed temperature, and coverings should be used to maintain a relatively high bed temperature. Before emergence, generally do not remove the film or open the window for ventilation. When the young shoots begin to push through the soil and emerge, if the covering soil is too thin and shell-topping is found, cover with soil again immediately.
② Seedbed management from emergence to before transplanting: This period is mainly about regulating seedbed temperature and humidity, thinning seedlings in time, covering with soil, improving light conditions, and controlling seedling stage diseases. After the two cotyledons of the seedlings have fully unfolded, the bed temperature should be appropriately lowered, controllable at 20-25°C during the day and 10-15°C at night, to prevent excessive growth. 4-5 days before transplanting, in order to adapt to the lower temperature of the transplanting bed, increase the survival rate after transplanting, and promote recovery, the bed temperature can be lowered by another 2-3°C at this time. For cold bed seedling raising, especially hotbed and greenhouse seedling raising, the ventilation openings should be gradually enlarged during the day, the ventilation time extended, and straw mats or thin mats should also be gradually uncovered earlier and covered later to extend the light duration. The damping-off or seedling blight that easily occurs during the seedling stage is often caused in bad weather by not carrying out proper ventilation and air exchange, and by covering for a long time with straw mats, films, and other coverings, causing the air humidity in the seedbed to gradually increase. During this period, special attention should be paid to protecting the cotyledons, improving light conditions, thinning seedlings at the right time, water and fertilizer management, and reasonable soil covering.
Growing conditions for tomatoes
1. Temperature: Tomato is a warm-loving vegetable. Under normal conditions, the optimum temperature is 20-25°C, and the optimum soil temperature for root growth is 20-22°C. Increasing soil temperature can not only promote root development, but also significantly increase the nitrate nitrogen content in the soil, accelerate growth and development, and increase yield.
2. Light: Tomato is a light-loving crop, with a light saturation point of 70000 lux and a suitable light intensity of 30000-50000 lux. At the same time, in the process of transitioning from vegetative growth to reproductive growth, it basically requires short-day conditions, but the requirement is not strict.
3. Water: Tomatoes need a relatively large amount of water, but they do not need frequent large irrigation. Generally, a soil humidity of 60-80% and an air humidity of 45-50% are suitable. High air humidity not only hinders normal pollination, but under high temperature and high humidity conditions, diseases are severe.
4. Soil: Tomatoes are not very strict about soil conditions, but to obtain high yield and promote good root development, deep, well-drained, fertile loam rich in organic matter should be selected, with a pH of 6-7 being suitable.
Cultivation and management techniques for tomatoes
1. Growth period management. This includes measures such as intertillage and weeding, storing water and preserving soil moisture, staking and tying vines, pruning and removing side shoots, removing old leaves, ventilation and light transmission, strengthening disease and pest control, and strengthening temperature management. Temperature management means appropriately increasing the ventilation volume of the greenhouse during the day so that the temperature inside remains around 25°C. At night, the temperature should remain between 10-13°C. When ventilation begins, the ventilation openings should go from small to large and from few to many, and after the temperature drops in the afternoon, gradually make the openings smaller or close them.
2. Fertilizer and water management. During the growing period of tomatoes in the summer and autumn rainy season, watering is generally not needed, but when drought occurs as the 1st to 3rd trusses of fruit mature, appropriate watering should also be done. According to the growth condition of the tomato plants, topdress in a timely manner to promote fruit development and preserve flowers and fruits. Generally, microbial bacterial fertilizer can be applied as base fertilizer, and Beizhuang seedling agent and Zengtianling can be applied as topdressing to make them look better and taste more delicious. If conditions permit, cake fertilizers such as soybean cake and cottonseed cake can be applied as topdressing.
3. Pruning management. During the growth process of tomatoes, tender shoots will grow from each leaf axil. The tender shoots below the first inflorescence should be removed in time to avoid consuming nutrients and affecting fruit light exposure and yield. After leaving 4-6 inflorescences per plant, pinch off the growing tip of the tomato plant to control nutrients so they are supplied only to the fruit and ensure yield.
In addition to good seedling raising, management during the planting process and attention to the growth habits of tomatoes are also very important. The growth of all things has its own unique growth cycle, so we should respect their growth habits and act strictly according to their patterns.