Do I need a plan
We do not quote or install irrigation without a plan, this way there are no surprises and hopefully this way we don’t forget anything.
Subsurface / Drip irrigation
Sub surface irrigation has many advantages over traditional sprinklers
- Reduces water loss due to evaporation
- Water is placed where the plants need it most, right at the root zone and not on the leaves
- Uniform watering over the whole garden. No sprinkler shadowing by other plants
- Reduces water runoff, slow application rates allow the water to soak in
- No over spray on to paths and the house, eliminates bore stains
- Reduces disease in plants caused by over head watering, particularly Natives and Roses
- Damage resistant, no sprinklers to snap when you drive or mow over it.
I have heard subsurface irrigation gets blocked
Subsurface irrigation has been around for almost 20 years in Australia, some of the older technology and low flow small drippers did clog but Drip Irrigation has come a long way since then. Modern systems have highly engineered self cleaning drippers embedded into the pipe, provided they are installed correctly drippers should never clog and if they do it is a simple matter to flush them out.
Water wise sprinklers
We stock and use a range of rotary nozzle low flow sprinklers. Low flow sprinklers have large droplets of water that are sprayed out in multi streams so are more wind resistant than traditional sprinklers. The low flow also means the water comes out slower so it has time to sink into the ground thus reducing run off. Note they do need to be run for longe
r than standard spray head sprinklers to apply the standard 10mm drink. The sprinklers can be adjusted for angle of spray and radius. We do not recommend using sprinklers in garden beds as plants can get in the way and cause uneven watering.
How long do I run my sprinklers
It will depend on the type of system you have; you are aiming for 10mm of water twice a week for Scheme Water Systems and 3 times a week for bores.
- As a rough guide a lawn with subsurface drip irrigation will need 22 minutes
- A garden with sub mulch drip irrigation will need 12 minutes
- A lawn with low flow sprinklers will need 45mins
Refer to our detailed PDF for exact run times for particular types of drip line. We will give you this information when we install your system.
The water corporation has suggested times on its web site
How many stations will I need
Irrigation systems work best when the watering zones are within a certain size range, for example scheme water with a flow of 2,500 Litre/Hr will water about 75m2 of garden with drip line comfortably. It is better to have smaller zones than larger, often a large lawn will be broken into 2 or 3 sections. We always keep garden beds separ
ate from lawns and will put vegetable beds and pots on their own stations. In an average garden you will have 4-6 zones or
Hydro zoningstations. This is called “hydro zoning” and will ensure every garden gets watered evenly and for the appropriate time for it’s own sun or shade micro-climate.
Hydro zoning is the fancy name they give to grouping like plants together.
- High water - Pots that need watering often for 2 minutes at time
- High water - Vegetables & Fern/wet tropical gardens
- Moderate to High water - Lawn
- Low to Moderate water plants – Eastern states natives, Mediterranean, Roses, Fruit trees
- No to Low water plants – WA natives, plants from South Africa, California, succulents
- No water plants – Cacti, some natives once established, all plants will need water over their first summer and if it stays over 40o for a week.
Note on succulents – succulents do need some water to thrive; they will survive without but will not flower and look plump.
Soil preparation
It is imperative you improve your soil when installing irrigation of any description. The soils in Perth are very water repellent and void of clays and organic matter. By increasing the clay content and organic matter in the soil you vastly increase the holding capacity of the soil for water and nutrients. We recommend you remove a 100mm layer of your existing sand and replace it with a soil mix high in clay and organic matter. By doing this your plants can make the most of the water you are putting on them and you will minimise run-off and leaching of fertilizers.
Mulch
- Cools the soil and reduces plant loss
- Suppresses weed growth
- Reduces wind erosion
- Enriches the soil as it breaks down
- Improves the look of the garden
Subsurface irrigation in the garden is laid on the soil surface and must be covered with mulch for it to conserve water and effective
Soil wettersly grow your plants; the mulch also hides it from view. You need to replace the mulch every few years; it is a great way to give your garden an instant face lift, apply soil wetter and controlled release fertilizer before you mulch. Just remember not the bury plants in the mulch, they can go rotten and die.
A newly prepared garden bed with good quality organic matter will stay water repellent for about a year depending on other factors in the garden. When a bed becomes water repellent it is important to apply a frog friendly soil wetter to ensure water is available for the plants. Ideally apply the soil wetter in April before the first rains to avoid rivets and puddles, and then every 2-3 months from October over summer. We stock Eco-Wet soil wetter in our shop.
Controllers
There are many controllers available depending on the number of stations required, whether it is indoors or outdoors, attached to a tap, the list goes on. A good controller should be programmable so you can run different zones for different times on set watering days. It should be easy to understand, if you can use a smart phone you should be able to handle an irrigation controller. Some controllers have 2 levels of controls, digital ones that are set and forget and manual ones which you can use to fine tune watering times or switch it off when it is rains. We will select the right controller for you and train you to use it.Rain Sensors
Rain sensors requirement in the near future for existing gardens, but is now mandatory for new gardens. Every brand works slightly differently and only with their irrigation controller. We stock ones that measure just rainfall and ones which measure several day rainfall and evaporation rate. A rain sensor will either switch off the irrigation; or more sophisticated controllers now measure the climate from the previous two days and reset the next irrigation programme to modify the next run time, they can significantly reduce the amount of water used.
Bores
Bores are a common feature in Perth gardens, we can connect an existing bore or get a new one drilled to use for irrigating your garden. If required we can add water conditioners to reduce iron staining. If you own a bore you can water 3 times a week rather than 2, it is still important to be water wise as the water in our aquifers is limited.
Fertigation
Fertigation is the act of passing liquid fertilizers through the watering system; it is used in many market gardens and nurseries. Fertilizers must be applied within the root zone in warm damp conditions for the plants to be able to utilize it. Spreading controlled release fertilizer on top of the soil in the sun just causes it to crack and dump its fertiliser, exactly what you don’t want. To counter this you need to put it under the mulch and dig it in, this can be quite difficult in an established garden. Fertigation delivers the fertilizer to where it is need, the root zone, in water to allow the plants to take it up with no digging.
Note: Water Corporation demand a backflow prevention device is installed before the irrigation where fertigation is used, no need for bores.
I am from the country and I just want the stuff to install myself
We will still draw a design and give you a quote and we can box up the bits you need to take with you. Collecting the pieces together and making sure you have everything can take up to an hour on top of the design so we will charge you for this service.
Earth & Water have installed over 1,500 systems, but only a few of these systems have been installed by the client on their own. In self installed systems you run the risk of unknowns and our design and take off only been 90% accurate. We cannot guarantee that our design and parts schedule is more than 90% accurate.
Source:http://www.earthandwater.com.au/content/page/irrigation-overview.html
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