How to raise seedlings of tomatoes in greenhouse in early spring? What are the technical points?

In early spring, the temperature will be more repeated, and there is often a sudden visit by cold air, which is extremely disadvantageous to the vegetable production in the greenhouse. For this reason, the majority of vegetable farmers are reminded to do a good job in the early spring management of vegetables in the greenhouse, so as to achieve the goal of increasing production and increasing efficiency. Let's take a look at the key points of tomato seedling raising in the greenhouse in early spring.

I. pre-broadcast preparation

(1) preparation of nutritious soil

The preparation of nutritious soil should meet three conditions: one is to select the pastoral soil that has not planted Solanaceae crops in 2 to 3 years and has not applied long-acting herbicides; second, the prepared nutritious soil can fully meet the needs of seedling growth; third, the ability of loosening and aeration, water and fertilizer conservation should be strong. Usually 6 parts of high-quality pastoral soil, 3 parts of fully mature high-quality farm manure, 1 part of fine crushed old slag or plant ash, evenly stirred and sifted, mixed with calcium superphosphate or diammonium phosphate 1: 2 kg/m 3, 40% pentachloronitrobenzene 25 g kg/m 3, 70% Dysen zinc 25 g kg/m 3, fully mixed and laid flat in seedling bed or nutrition plate (60 cm long and 24 cm wide), thickness 8 cm 10 cm, water enough to prepare for sowing.

(2) soaking seeds to accelerate germination and sowing seeds

One is to soak the seeds in warm water. Soak the seeds in 55 ℃ warm water for 15 min and stir while soaking to prevent scalding of the seed coat.

The second is pharmaceutical treatment. The soaked seeds were drained and then treated with 2.5% nitrile suspension seed coating agent (Shileshi) 200x solution or 1 million U agricultural streptomycin 600x solution, which could effectively control seedling quenching, bacterial blight and bacterial diseases.

Third, sprouting at room temperature. Put the foam box prepared in advance on the 28 ℃ hot Kang, then wrap the treated tomato seeds in gauze and put them in the box, turn them once in 3 to 4 hours, rinse them with clean water in 8 to 10 hours, and sow them when about 80% of the seeds are white. If the seeds can not be sowed in time in special weather, the seeds can be squatted in a cool place.

Key techniques of Tomato Seedling raising in greenhouse in early Spring

Second, sowing and raising seedlings at the right time

The planting time was determined according to the thermal insulation performance of the greenhouse, and then the specific seedling raising time was determined according to the planting time and seedling age. The seedling age of tomato in greenhouse in early spring is generally 80-90 days, and the planting time is about April 25. Therefore, the seedling raising time is generally chosen in the middle of January.

After sowing, the temperature in the seedling shed was kept between 28: 30 and 22: 25 ℃ in day and night, and between 22: 25 and 17: 18 ℃ after emergence. After the seedlings are unearthed, the light time should be prolonged as long as possible at the suitable temperature, and the seedlings can be shaded properly when the light is strong and the temperature is high at noon to prevent the seedlings from being burned. Generally, there is no need for secondary rehydration before emergence. If it is found that the seedlings are short of water after emergence, warm water can be sprayed with a sprayer to replenish the seedlings, and no heavy water or cold water can be poured to prevent adverse effects on the seedlings. Tomato cultivation in greenhouse in early spring is limited by temperature and cultivation methods. In order to achieve the purpose of early listing and higher income, the majority of growers often cultivate older seedlings for planting. The standard of strong seedling: plant height 2025 cm, stem diameter more than 0.6 cm, with 7-9 dark green spreading true leaves, the angle between petiole and stem is about 45 °, the first inflorescence is attached to node 7-9, and has begun to show buds, which requires that the root system is intact and free of diseases and insect pests.

In addition to fully meeting the conditions of water and fertilizer needed for growth, the adaptability of seedlings should also be exercised before planting. The transplanting arch shed should be uncovered early and late at 7-10 days before planting, and all the mulch should be removed gradually. The temperature should be kept between 15-25 ℃ during the day and 10-12 ℃ at night, so as to enhance the low temperature resistance of seedlings and slowly adapt to the temperature in the planting shed.

III. Transplant

The seedlings can be transferred to a nutrition bowl of 10 cm × 10 cm for management when they have two leaves and one heart. 1-2 days before seedling separation, the seedlings were sprayed with 1500x solution + 8000mu 10000-fold solution mixed with water for 15 kg. On the day of seedling separation, the nutrition bowl was poured through the bottom water. After the water was seeped, the seedlings were sprayed with 150 mL/hm 2 + 72.2% water agent 300 mL/hm 2 mixed with water 225 kg/hm 2, and then the seedlings were placed in a nutrition bowl with 1 plant per bowl and covered with 3 cm of soil thickness.

IV. Post-transplant management

In order to promote the early emergence of new roots, the temperature was mainly increased before retarding seedlings, and the temperature was kept between 28-30 ℃ in the daytime and 20-22 ℃ at night.

In order to ensure the normal growth of roots and prevent the excessive growth of seedlings from adversely affecting flower bud differentiation, temperature, water and light should be controlled mainly after seedling retardation, the temperature should be kept between 20: 25 ℃ during the day, 15: 18 ℃ at night, and the humidity should be controlled between 65% and 70%. It was found that seedling growth could be regulated by potassium dihydrogen phosphate solution 750 g/hm 2 + 1.8% Aidoshi 120 mL/hm 2 mixed with water 225 kg/hm 2. Increase the light time as much as possible after slow seedling, and use supplementary light in case of overcast and rainy days, so as to facilitate the early flower bud differentiation and promote the formation of late yield.

Prevention and control of diseases and insect pests

The main diseases and insect pests in tomato seedling stage are quenching disease, leaf spot disease, aphid, whitefly and so on. After transplanting slow seedlings, 96% trimethoprim 3000 ~ 5000 times solution, 72.2% Pulike water agent 800 times solution, 72% urea ·manganese zinc wettable powder 500 times solution, 22.4% spiroethyl ester 3000 times solution + 3% acetamiprid 1000 000 times solution can be sprayed once every 7 days to control the occurrence of early diseases and insect pests.