How to Water Tomatoes in Greenhouse?

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1. Tomato watering method in greenhouse
 
Method that Watering under the film between ridges is generally adopted when choosing the planting method of wide-narrow double row cultivation system with plastic film mulching between ridges. The wide row spacing is 80cm, the narrow row spacing is 50cm, and the ridge height is 10-15cm with one row of seedlings planted per ridge. Cover two adjacent ridges with two mulches. Plastic films or dried wheat straw, rice straw and things alike are simultaneously covered between wide rows (operation rows).
 
It has been determined that the use of inter-membrane watering can increase the ground temperature by about 5℃, reduce air humidity 9%-10% to reduce the insect attack more than 30%. According to the data, the use of drip irrigation for soil thinning resulted in a much lower water to yield ratio and less variation in ground temperature.
 
2. Watering frequency and volume
 
Due to different growth periods of tomatoes, giving appropriate watering frequency and amount should be considered. Generally, in severe winter, when the air temperature and ground temperature in the shed are relatively low, the watering volume should be small and the interval should be long. Do not flood it to prevent tomato root retting caused by low temperature and high humidity.
 
When planted in time, the seedlings should be watered in a timely manner, and the watering should be properly controlled during the growth period of low-temperature tomatoes. When the first batch of tomatoes starts to expand, the amount of watering should be gradually increased. In fruiting season,  sufficient water is always needed with soil moisture content in the shed not less than 20%. Learn to control the amount of water when the small amount of water will definitely affect the yield of tomatoes while excessive amount of it will cause soil hypoxia leading to root rot, and it would be difficult to raise the ground temperature by watering too much at a time. The amount of watering depends on the water consumption of tomatoes, soil evaporation and the degree of roots tolerance.
 
3. Selection of watering time
 
Watering should be done on a sunny morning. Try to avoid watering in the afternoon or on overcast days, otherwise insect attack will happen due to excessive humidity in the shed. Particular attention should be paid to raise shed temperature properly on that very day and the day before when timely dehumidification is needed after watering.
 
Watering method should be distinguished between cloudy days and sunny days. When temperature is high on sunny days, the amount of watering should be gradually increased. If it is cloudy, little or no irrigation is required. Do not water on continuous rainy days. When the weather changes from sunny to overcast, the amount of water should be gradually decreased and the interval should be appropriately extended. Watering and fertilizing should be carried on together as far as possible, after which ventilation should be done properly as required.