When is the right time to transplant greenhouse and open-field tomatoes? How many days later should you water and spray? What are the cultivation and management techniques?
Tomato, that is, the tomato, also known as fan qie and yang shi zi, is fleshy and juicy, with yellow seeds, and flowers and fruits in summer and autumn. It originated in South America and is widely cultivated in both northern and southern China.So when is the right time to transplant tomatoes? How many days later should you water and spray? What are the cultivation and management techniques?
When is the right time to transplant tomatoes?
1. For early-maturing cultivation under protection in spring, transplant in late February to early March, seizing the weather at the tail end of a cold spell and the start of a warm one;
2. For open-field cultivation with plastic film mulching, transplant around March 20, seizing the weather at the tail end of a cold spell and the start of a warm one;
3. The transplanting density is as follows: for early-maturing varieties with multi-stem pruning, row spacing 50×30 cm, about 3000 plants per mu; for mid- and late-maturing varieties with single-stem pruning, about 3500 plants per mu; when using double-stem pruning, about 2000 plants per mu.
How many days after transplanting tomatoes should you water and spray?
1. As an early preventive measure, you can spray an 800-fold liquid plant protection coat every half month to enhance the plant's stress resistance and photosynthesis, prevent infection by diseases and insect pests, and ensure the tomato fruit set rate.
2. About 20 days after transplanting, per mu you can use 100 ml of 25% azoxystrobin + 400 g of 70 imidacloprid + 1000 ml of 5% abamectin companion (Genlishu), mix with 200 kg of water, aim the nozzle at the base of the tomato stems and spray, applying 50-100 ml of the solution per plant.
3. In spring and winter, temperatures are low, ground temperature rises slowly, and water transpiration is poor. When a heavy watering is given, it is easy for the root system to remain in a low-temperature, high-humidity environment for a long time, causing root rot and then triggering various diseases. This is especially true when bad weather occurs, which further aggravates the development of diseases.
The reasonable approach should be to water lightly. For 1-2 days after transplanting, raise the temperature appropriately; the greenhouse temperature can be raised to 30°C during the day, and the night temperature controlled at 16-18°C. After 2 days, gradually increase ventilation. Two days before the second watering, irrigate the roots. You can choose: 95% hymexazol 3000-fold, propamocarb hydrochloride 750-fold, or Keshade Sanqian for root irrigation. At the same time, before transplanting, it is recommended to dip the roots with phosphorus and potassium source reservoir.
4. The seedling-recovery water is generally given 8-10 days after transplanting according to the weather and conditions in the greenhouse. In spring and winter, roots grow slowly, and after the earlier recovery period, new roots have gradually begun to grow when the seedling-recovery water is applied. Applying rooting substances such as humic acid and seaweed extract can effectively promote the number and growth rate of roots. At the same time, the seedling-recovery water can be slightly larger than the transplanting water. During this period, vegetable growers will carry out farming operations such as hoeing and laying plastic film, so root irrigation may not be needed.
5. In winter, the third watering is generally given 25-30 days after transplanting, when the plants enter the flowering and fruiting stage. At this time, the roots have basically grown out and formed a root skeleton composed of thicker roots, and the root coverage range has also expanded beyond a diameter of 20 cm.
At this time, carbendazim can be applied with the water to carry out a large-scale soil sterilization and protect the further healthy growth of the root system.
What are the tomato cultivation and management techniques?
1. Nutrient solution management after transplanting
The pH value of the nutrient solution is controlled at about 6.5, the EC value of the nutrient solution is controlled within 2.5-3.0 ms/cm, the liquid temperature of the nutrient solution is controlled within 18-20°C, and the nutrient solution circulation time is 10-20 hours per day. When the plants enter the flowering and fruiting stage, add 50-100 g of potassium sulfate per ton of nutrient solution each week.
2. Pruning
Pruning a tomato tree is different from pruning ordinary tomatoes. Ordinary tomatoes are pruned with a single stem, and all side branches must be removed, while tomato trees are pruned using the continuous double-stem pruning method, retaining 2 growth points on each branch, keeping all strong side branches that grow, and removing only some weak side branches. A single tomato tree will have hundreds or thousands of growth points. At the base of the side branches, use strings to guide them onto the cultivation frame, and the branches that reach the cultivation frame must also be evenly distributed in order without shading or pressing each other.
3. Flower retention time
If the tomato trees are grown for sightseeing, the one-time flower retention method can be used, that is, all flowers that open before the plants reach the cultivation frame are removed, and all flowers that open after the plants reach the cultivation frame (100-120 days after sowing) are retained. To ensure fruit set, spray flowers with 20-40 mg/kg Baoguoning. Keep 4-5 fruits per cluster of flowers.
4. Foliar fertilizer spraying
To increase nutrient supply to the plants, carry out foliar fertilizer spraying every 7-10 days. Where conditions permit, carbon dioxide can also be applied additionally.