How to install a garden watering system

Step 1: Check the water flow rate

Your system will only be as good as your water pressure. So the first thing is to measure the flow in litres per second from the garden tap. You need to know this to tell how many and what type of sprays can be serviced at any one time. This is easy to find out. First, turn off all taps. Then turn one garden tap on full into a 9-litre bucket, but not through the hose. With your watch ready, time how long it takes to fill the bucket in seconds.

Then divide the bucket size by the time to fill in seconds, and multiply by 60. This will give you your flow rate in litres per minute. For example:

9 litre bucket ÷ 20 seconds x 60 = 27 litres per minute

The types and number of sprays you can use at any one time varies according to the brand. So use your flow rate and check the manufacturer’s brochure in planning your system.

Step 2: Pick you system

DRIP SYSTEMS

Available as fixed or variable types, deliver just the right amount of water to vegetables, pot plants, trees and shrubs at a rate the soil can readily absorb. In allowing the right number of drippers, think about your soil type and what the plants need. As a rule of thumb, allow about 1 dripper for every 50cm of foliage diameter, but for sandy soils space about 35cm apart. For larger trees, form a loop around the base.

MICROSPRAY SYSTEMS

The most popular and provide a spray or mist. They come in a quarter circle, half circle and full circle, and are ideal for flowers, vegetables and plants that require moisture on their leaves and in areas such as flower beds, rockeries, compact gardens and rows of crops. They also avoid the problems of soil compaction and water run-off, spraying the water where it is wanted, not on fences, walls, paths or driveways.

POP-UP SPRINKLERS

A neat, effective way to water lawns – not only do they provide good even spread of water, but think of the time it’ll save you. No more shifting sprinklers, no more handheld hoses. Pop-ups generally come in four pattern types – quarter-circle, half-circle, 3/4 circle and full circle. The number you’ll need will depend a lot on your water pressure. When setting out your system, it is a good idea to form a loop for a more even distribution of spray.

Step 3: Sketch yourself a plan

Draw up a plan of your garden. The easiest way is on graph paper. Sketch in building outlines, the position of pathways, the width of garden beds, the location of trees and any obstacles so you can see the actual areas you want to water. Then mark in where the main poly tubing from the tap is to go. Off this, mark where distribution lines are to go for the areas to be watered and mark where drippers or microsprays are needed. The main tubing can be a larger diameter than the tubing used as distribution lines so that more than one distribution line can be run at a time. However, you cannot place a dripper and a microspray on the same line. They are designed for different types of plants and different watering rates.

Then, using the manufacturer’s brochure, write up a shopping list of how many sprayheads, drippers, tubing and accessories you need. Or take your plan to your Mitre 10 store and ask them to give you a hand.

Step 4: Installing

Drip & Microspray Systems Using your plan, lay out all the parts where you intend to install them. Use bricks or stakes to hold the poly tubing in position. Working from the tap in the direction of the water flow, adjust the layout till the main tubing and distribution lines are suitably located and cut the poly tubing to length with your utility knife or secateurs. Connect all tubing with joiners, elbows or tees to form the desired layout. Secure each connection with a locking clamp and be sure there are no kinks in the poly tubing.

For Drip and Spray systems, seal the open end with an end stop. Pierce the poly tubing with the hole punch – this must be a straight, clean punch with no wobbling side to side. Then, push the dripper or spray inlet into the hole. Cover the tubing with soil leaving the drippers exposed.