1. Introduction
Tomato seedlings require adequate moisture during growth period. Quantity of water required varies according to soil type and climatic conditions. Timely irrigation results in to seedlings healthy, vigorous and resistant to pest and disease attacks.
Nursery beds should be irrigated lightly but frequently with a rose can. Duration between 2 irrigations varies from 3-5 days in summer and days in winter.
Withholding the water for 3-5 days before uprooting the seedlings for transplantation can hardens the plants and reduces mortality in field. But nursery beds must be watered just before uprooting seedlings to minimize damage to roots. .

2. Irrigation Time and Scheduling
Tomato plants should be watered in the morning for most efficient use of water as it gets more time to soak in soil before high temperatures which can cause evaporation. Watering in the evening should be avoided as it provides conducive humidity and environment for attack by pests and diseases.
Irrigation frequencies vary with soil type and climatic conditions. Lighter soils require watering twice a week while heavier soils can be watered only once a week.
Watering is more frequent in summer while it is delayed in winter season and almost absent in monsoon season.

3. Methods of Irrigation Surface irrigation / Flood irrigation
Simplest irrigation method where water is allowed to flow freely into flat or furrowed farms.
Advantages
It is comparatively cheap, as the infrastructural cost of this type of irrigation system is minimum.
Water quality and climatic conditions cannot affect application of irrigation to nursery.
Disadvantages
Flood irrigation may increase soil borne diseases and weed growth.
Increase soil salinity in heavy soils and cause water logging.
Time and labour required for application of water is large.

4. Methods of Irrigation
Surface Irrigation
Sprinkler Irrigation

5. Sprinkler Irrigation
Sprinkler irrigation system is widely used in greenhouse grown tomato nursery. Sprinkler heads are placed underneath the crop.
Advantages
Water distribute evenly on large area and can irrigate various crops at one time.
Saves water in comparison to flood irrigation and very useful in improving microclimate like increasing humidity and reducing soil and air temperatures.
Disadvantages
Water distribution can be affected by wind velocity.
Infrastructural cost and power requirement of the system is more .

6. Drip Irrigation
Drip irrigation is advanced method of irrigation, which can be used to apply water and nutrients direct to the root zone.
Advantages
Saves 40 – 50 % water. Fertilizers can be applied through system
Seedling establishes quickly and less attack of pest and diseases.
Disadvantages
Infrastructural cost is high.
It increase salt concentrations in top soil.
Drip Irrigation