There are three main ways of watering a garden: hand-held devices, fixed systems and movable sprinklers. Hand-held devices such as watering cans and hoses are the cheapest options, but hoses are wasteful and watering cans can be time-consuming to use. Fixed systems can be expensive to set up but are reliable once installed and with careful planning can be used to make the most out of your water usage. With the exception of sprinklers attached to hose pipes, movable sprinklers are more suited to irrigating commercial crops and large areas since they must be transported from paddock to paddock.

• Drippers - these are micro-irrigation plastic drippers, also called emitters, which are affixed to PVC piping and can be placed on the soil surface next to plant roots, or buried beneath the surface.
• Soaker hoses - these are perforated pipes which are usually placed beneath the soil surface close to plant roots. They can also be laid on the surface but may degrade quicker.
• Micro-sprays or spray nozzles - these are emitters affixed to pipe which spray water rather than emit droplets.
• Micro-sprinklers - these are spray connectors on risers which can be used as part of a micro-irrigation system. Sprinkler heads may have different watering angles (e.g. 90°, 180°, 270°, or 360°).
• Pop-up sprinklers - these are larger sized sprinklers which retract below the surface after use.
• Capillary irrigation - this is where water is drawn up through the soil by capillary action. Water-well pots and containers work on this principle.
• Hand-held hose - a hose is good for an emergency but can be wasteful. Consider adding a sprinkler attachment for lawn areas – remember though that in many areas there are restrictions on watering lawns though. A gun attachment can enable more targeted application.
• Watering can – these are generally less wasteful than hoses, but more laborious to use.

 

Trickle irrigation systems are the choice of many home gardeners because you can target your watering and only use the water you need. In these systems, tap or tank water is distributed via interconnecting polyethylene or PVC pipes. These deliver water at low pressure via small emitters directly to the soil, or through spray nozzles which target specific areas of the soil. Dripper pipes which have a series of emitters can be buried below the surface, or drippers and spray nozzles may operate on top of the soil surface.

 

Trickle irrigation systems are appropriate for wide range of gardening applications, including irrigation of vegetable row crops, orchards, established feature trees, garden beds, and all kinds of container plants. Misting nozzles can also be used where high humidity is required, such as in a greenhouse for propagation.

 

Trickle irrigation systems deliver water far more slowly than most other irrigation methods, and are frequently less wasteful of water. Some soils are less suitable for this type of irrigation. For instance, sandy soils can drain and dry out too quickly for trickle systems to be effective. Adequate filtration is necessary for effective operation of trickle systems because the small emitter sizes can easily be blocked by impurities in the water.

 

• Water conservation - water is directed exactly where the plant needs it most, the plant roots. Loss of water from wind and excess runoff is minimised.
• Saves labour - although trickle systems are initially time-consuming to set up and occasionally require some ongoing maintenance, they are permanent fixtures which are fully automated. Busy work schedules and holidays are no longer a problem with such a system.
• Does not get water where it is not wanted - people, paths, furniture and other items close to the water outlet do not get wet when the system is on.
• Reduces weeds - weeds have less chance of germinating because less area of the soil is moist.
• Reduces disease outbreaks - drippers do not wet the foliage and flowers which would leave them more susceptible to fungal diseases.
• Targeted watering - water can be directed to individual plants such as potted plants, isolated trees, and shrubs.
• Heavy soils - they work better in heavy clay soils where water penetration is slow.
• Concentrated wetting pattern - means they are ideal on steep slopes, if located up the slope from the plant, for minimising erosion.
• Low pressure - they still work when water pressure is extremely low.

 

• In sandy soils you can apply a lot of water quickly and it will be absorbed.
• In heavy clay soils you must water slowly over a long period (heavy applications will not soak in, and a lot will be lost as runoff).
• Deep-rooted plants such as trees should be watered slowly over a long period, so as to wet the soil to a great depth.
• Deep-rooted plants can be watered less often.
• Shallow-rooted plants such as annual flowers and vegetables need frequent watering, but of a shorter duration at each watering.

Benefits of Studying This Course
This course assumes you have some prior understanding of irrigation either through one of our other irrigation courses e.g. Irrigation (Gardens) or through industry experience. Students learn about how to design irrigation systems for a variety of purposes and different types of sites. There is also greater emphasis on managing irrigation systems and troubleshooting. The course will have greatest appeal to people working in the following areas:

• Irrigation Management & Design
• Garden Design
• Landscaping
• Horticulture Foreman or Managerial Roles
• Head Gardener
• Parks & Gardens