Rules of Watering

a. Rule 1: Use a well-drained substrate with good structure

• If the root substrate is not well drained and aerated, proper watering cannot be achieved.
• Hence substrates with ample moisture retention along with good aeration are indispensable for proper growth of the plants.
• The desired combination of coarse texture and highly stable structure can be obtained from the formulated substrates and not from field soil alone.

b. Rule 2: Water thoroughly each time

• Partial watering of the substrates should be avoided; the supplied water should flow from the bottom in case of containers, and the root zone is wetted thoroughly in case of beds.
• As a rule, 10 to 15% excess of water is supplied. In general, the water requirement for soil based substrates is at a rate of 20 l/m2 of bench, 0.3 to 0.35litres per 16.5 cm diameter pot.

c. Rule 3: Water just before initial moisture stress occurs

• Since over watering reduces the aeration and root development, water should be applied just before the plant enters the early symptoms of water stress.
• The foliar symptoms, such as texture, colour and turbidity can be used to determine the moisture stress, but vary with crops.
• For crops that do not show any symptoms, colour, feel and weight of the substrates are used for assessment.

Advantages of Micro-irrigation

• high level of irrigation efficiency (low risk of runoff)
• distribution of small volumes over long irrigation time
• possibility of irrigating during warmest hours
• reduced development of weeds
• reduced risk of pathogen attacks because of the low air humidity generated by these systems (moreover, the small wetted area from non-spray type micro irrigation limits weed growth and, consequently, disease incidence)
• absence of soil compaction
• low operating pressures with consequent reduction of energy costs
• possible adoption of fertigation