A watering system can mean the difference between your garden thriving or struggling. It can also reduce the time you spend bucketing or hosing water onto your plants.
Take Stock
Have a good look over your garden. Think about the things that required so much time watering last year…or the plants that suffered most because you never got around to watering them.
Every garden is different. For some people, it’s the lawn that suffered most; for others it’s the pot plants on the veranda; and for others it may be the vegetable garden.
Target those problem areas for an irrigation system that can deliver regular water. You’ll be delighted at how much difference regular watering makes.
Different Gardens need different Watering Systems
1. Lawns
Because there are no branches or leaves to get in the way, sprinklers are the best method for irrigating lawns.
If you have a large lawn area, then the best system is pop-up sprinklers. These types of sprinkler distribute water over a wide area. They also slip back into the ground when not in use, keeping them out of sight and out of the way of the lawn mower.
For small lawns use fixed sprinklers positioned at the edges. They still provide good coverage without interfering with lawn mowing.
2. Shrubberies and Garden beds
The type and design of the irrigation system you choose for a garden bed will depend on a number of factors:
The type of soil – sandy soils will readily absorb water, whereas clay soils can only absorb a small amount of water at a time. Sprinklers and sprays usually work well in sandy sites, but you will probably need to install micro sprays or drippers for clay garden beds.
The layout of the garden bed will determine where you can install irrigation outlets. Placing a sprinkler right next to tree or bushy shrub will prevent an even distribution of water.
Established plants may not need any additional irrigation.
Areas under trees may need extra water.
Garden beds with annual plants and vegetable seedlings will need to be kept from drying out.
Some plants, particularly roses, are prone to fungal diseases. Do not direct water onto the leaves of these plants.
3. For Hanging Baskets
Hanging baskets are very prone to drying out, especially when they are exposed to the sun and wind. Because sprinklers and sprays will wash out the potting mix, it is best to water them with micro sprays or drippers.
4. Tubs and Pot Plants
Like hanging baskets, pots are best watered with micro sprays or drippers.
Sprinklers
Different sprinklers have different features.
Costs vary.
Pop up sprinklers will slip back into the ground after use. These can be a blessing in areas with lots of people walking or running around.
Depending upon specifications, sprinklers can be adjusted to send the water at varying angles and at variable arc.
Different materials provide varying levels of durability.
Some sprinklers will only operate when there is sufficient water pressure.
Designing Your System
The number of fittings you can attach to your irrigation system will depend upon how much water flows through each fitting. Calculate the flow rate through your tap (see below), divide this by the flow rate through the type of fitting you want to use, and this will give you the number of fittings you can attach to each pipe.
NEVER put different types of fittings (eg. sprinklers and drippers) on the same pipe. The different flow rates will mean that one or other of the fittings will not work at its optimum level. If you require different types of fittings, use a separate pipe.
If you need to have more than one pipe, you will need to install a manifold at the tap. This is simply a mechanism for turning the different pipes on and off.
Remember, if the water has to flow up hill, you will lose water pressure, which will simultaneously lower the flow rate. The flow rate will also be lowered if you operate other taps when you are irrigating.
Alternatively, if the water is flowing down hill, the water pressure will increase. If the flow rate is higher than what is required for your system, you will need to be careful you don’t turn the tap on too hard as this may cause the fittings to break apart.
How to Calculate Flow Rates
Turn off all taps around the house.
Place a 10 litre bucket under the tap.
Turn the tap on full.
Time how many seconds it takes to fill the bucket.
Divide the time taken by ten to give you the rate (litres per second) that water flows through your tap.
Dripper or Spray?
Drippers take a long time to water a garden area. Water from sprays can evaporate and/or be blown away by the wind.
Cheap Micro-irrigation
Micro-irrigation systems are easy to install yourself. Use high density polyethylene (HDPE) pipe. This is flexible and easy to cut and join together. This type of material is best suited for use with microsprays and drippers. Its flexibility makes it ideal for irrigating pots and hanging baskets.
There are some disadvantages to using HDPE pipe and fittings:
Above-ground fittings are easily damaged.
Pets and other animals can ruin fittings trying to get water.
Sunlight can cause some plastic heads to go brittle.
Reach may be limited.
Small pipes may become clogged (this problem can be minimised by including a filter).
Small pipes may be cut by spades, secateurs, picks etc.
Handy Hint!
When installing a new micro irrigation system, lay the pipe in the trench. Before you install the fittings, run water through the system. This will straighten the pipe and ensure that fittings will be correctly positioned.