High-Yield Grafting Cultivation Techniques for Overwintering Tomatoes in Solar Greenhouses

Abstract:Select varieties with strong disease resistance, soak seeds to promote germination, use decomposed pen manure and pathogen-free mature soil as culture soil, add an appropriate amount of nitrogen, phosphorus and potassium compound fertilizer, sow in mid or late August, transplant when seedlings grow to 4-5 leaves, apply an appropriate amount of nitrogen, phosphorus and potassium compound fertilizer, etc., and after watering thoroughly, cover with plastic film in time; during this period, manage temperature and light well, and spray pesticides such as Buzhuchongmake and Sukeling to control diseases and pests.

I. Varieties

For cultivating overwintering tomatoes in solar greenhouses, you can choose mid-to-late maturing pink-fruited or red-fruited varieties with strong disease resistance (leaf mold, gray mold, viral diseases, early blight, late blight, etc.), tall plants, excellent quality, high yield, large fruit type, and relatively good storage and transport tolerance, such as Maofen 802, L402, Israel R144, etc.

II. Seed Soaking and Germination Promotion

1. Soak seeds in water at 50-55°C, stir until the temperature drops to 30°C, then soak for another 3-4 hours, then soak in 10% trisodium phosphate for 10-15 minutes.

2. You can also soak seeds in 500-fold potassium permanganate solution for 20-30 minutes, remove them, wash off the liquid medicine on the seeds, then place them in a 25-28°C environment to promote germination.

III. Seedbed and Culture Soil

1. You can make high beds and then use shade nets, etc., for shading, rain protection, and aphid-proof seedling cultivation.

2. You can use 1/3 fully decomposed pen manure and 2/3 pathogen-free mature soil, break up lumps finely and sieve to make nutrient soil.

3. Generally, for each cubic meter of culture soil, add 1 kg of diammonium phosphate and 5 kg of plant ash, or 2 kg of nitrogen, phosphorus and potassium compound fertilizer, then evenly mix in 80 g of 50% carbendazim.

IV. Sowing

Sow after 60% of the seeds have sprouted. You can choose to sow in mid or late August. Before and after sowing, spray pesticides around the seedbed to control aphids, etc.

V. Seedbed Management

During high-temperature weather in the daytime, provide shading. The seedbed temperature must not exceed 30°C. On rainy days, cover with film to protect against rain. To avoid excessive seedling growth, at the 2-true-leaf stage, spray 1000 mg/kg chlormequat once.

VI. Seedling Separation

1. When seedlings grow to 2-3 true leaves, separate the seedlings into a pre-prepared nutrient soil seedbed with a row spacing of 12 cm and a plant spacing of 12 cm, or separate them into nutrient pots with a diameter of 10-12 cm.

2. During the seedling recovery stage after separation, provide appropriate shading at noon, maintain the seedbed temperature at 25-30°C during the day and 18-20°C at night.

3. After seedling recovery, maintain the temperature at about 25°C during the day and 15-18°C at night. A few days before transplanting, appropriately lower the seedbed temperature to harden the seedlings. When the seedlings grow to 4-5 leaves, spray 1000 mg/kg chlormequat once more.

4. If using the Maofen 802 variety, during seedling separation, hairy and hairless plants need to be separated separately, then transplanted in separate sections to facilitate later management.

VII. Disease Prevention During the Seedling Stage

During the seedling stage, spray fungicides 1-2 times to prevent diseases. Generally, 200-250 fold Bordeaux mixture is a suitable protective agent, that is, 1:1:200-250.

VIII. Fertilization and Land Preparation

15-20 days before transplanting, apply 5 cubic meters of decomposed high-quality organic fertilizer per mu, 50-60 kg of nitrogen, phosphorus and potassium compound fertilizer, and 100 kg of superphosphate. After fertilizing, plow deeply and rake level.

IX. Cultivation Method and Transplanting

1. You can adopt the method of wide and narrow rows and small high beds, that is, north-south oriented beds, with a wide row spacing of 80-90 cm and a narrow row spacing of 60-70 cm, first making flat beds.

2. Plant two rows per bed, with a plant spacing of 30-35 cm, and transplant 2500-3000 plants per mu.

3. Then transplant from late September to early October. After planting, water thoroughly, and after the ground dries, hoe shallowly.

4. After waiting 7-10 days, cultivate deeply and earth up around the plants to form small high beds, then cover with plastic film.

X. Before and After Seedling Recovery

1. During this period, cover with film, maintain the room temperature at 28-30°C during the day and 17-20°C at night, and the soil temperature must not be lower than 20°C, which helps promote seedling recovery.

2. After seedling recovery, appropriately lower the room temperature, maintain 22-26°C during the day and 15-18°C at night, and spray 1000 mg/kg chlormequat 1-2 times to prevent excessive plant growth.

3. Then prune to a single stem, and promptly remove side shoots and tie the plants. During this period, control watering, and you can lift the plastic film for cultivation to promote root growth and control plant growth.

XI. Before and After Fruit Set of the First Inflorescence

To avoid flower and fruit drop caused by low temperatures, during this period you can spray flowers with 30 mg/kg 4-CPA. After fruit set, appropriately thin flowers and fruits, leaving 3-4 fruits per cluster. When the fruit of the first inflorescence is about the size of a walnut, water under the film in the middle of the high bed, and apply 15 kg of urea per mu with the water, or apply decomposed soybean cake water, etc. It needs to be watered thoroughly. During the overwintering period, control the amount of watering.

XII. Management of Temperature, Light, etc.

During the growing period, promptly uncover and cover the straw mats, and extend the lighting time as much as possible. In cloudy and snowy weather, also uncover and cover them, which helps the plants receive scattered light. Keep the indoor temperature at 20-30°C during the day and 13-15°C at night. The minimum night temperature must not be lower than 8°C. When the midday temperature reaches 30°C on sunny days, open the skylight for ventilation.

XIII. Carbon Dioxide Fertilization

During the overwintering period, the room temperature is relatively low, so ventilation is limited. If organic fertilizer is insufficiently applied indoors, carbon dioxide will be deficient, so on sunny mornings from 9-11 o'clock, apply 600-800 mg/kg carbon dioxide.

XIV. Disease and Pest Control

Spray pesticides such as Buzhuchongmake and Lesben to control aphids, leafminers, whiteflies and other pests. You can choose Sukeling, chlorothalonil smoke agents, or dust agents used alternately, which helps control gray mold, leaf mold, early blight, late blight and other diseases.