Installing Nursery Irrigation

Getting it Right from the Ground-Up Part II

This article Part II in a series of articles as featured in Australian Horticulture Magazine by Warren Downes, deals with what it takes to set up a development of this scale and the advancements in practices and technology involved. Downes Wholesale Nursery are undertaking a massive development of a 145 acre property at Theresa Park in Sydney’s west, developing it into one of the largest wholesale nurseries on the east coast of Australia.

As I write this, our 18 mega litre dam is well on its way to being filled by rain, and will be full in under 24 hours, thanks to careful planing at the earthworks stage. Our huge swale and sculpturing of the earth have created a catchment area of over 30 acres which will be expanded to almost double that with the addition of some pipe work. The property was reshaped so we could use gravity to control the flow of water through a series of drains and wetlands before reaching the dam.

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Rain Birds LF1200 sprinkler, showing no misting and water waste.

Construction of plant bed pads will begin shortly where our water recycling program will be further improved. Each plant pad will be formed into a shallow dish and lined with plastic to stop water penetrating into the ground. The dish will be lined with an Ag pipe that will guide the water to a drain system which leads to our wetlands for recycling and purification. Over the plastic and Ag pipe 100mm of crushed aggregate will be laid as a base for the pots to sit on. This reduces the risk of disease and provides excellent drainage.

We have selected the Rain Bird LF1200 impact sprinkler for the majority of our overhead irrigation. This sprinkler is a low flow head and has a good size droplet with no misting. Next time you see irrigation running, watch it closely and if you see a fine mist rising up above the sprinkler you are wasting water and increasing the humidity.

Being a low flow sprinkler, the LF1200 does have much longer run times than other impact sprinklers to achieve the same application rate. Run times will be up to 1 hour in summer, compared to around 20 minutes using other overheads sprinklers. This gives the advantage of better penetration and uniformity. You only have to tip a bucket of water over a lawn to see how a fast application will run off rather than penetrate the soil. The LF1200 is also useful for frost protection as it’s low application rate can be utilised to continually irrigate over long periods without wasting water. With Rain Birds SiteControl irrigation controller it can be programmed, so if frost protection does runs, it will cut it out of actual irrigation time, so that no water is wasted.

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Shows water waste with mist rising and dissipating into air.

Rainbird Sitecontrol irrigation controller

We have selected Rain Birds central controller SiteControl to take care of our irrigation control requirements. Kin Poon from Rain Bird writes;

Top nursery trusts Rain Bird technology to do the watering – “Downes Wholesale Nursery is one of the country’s largest suppliers of plants to the landscape industry. More than 500 species of Australian natives and exotic trees, shrubs, groundcovers and perennials are grown so watering is vitally important to the health of the plants and the business. The task will be made easy with the installation at the new site of a Rain Bird commercial central control system for single site applications known as SiteControl.”

“SiteControl offers powerful central control features for single, large contiguous site applications. It provides dynamic map-based control and instantaneous exchange of information between the field and the central computer. Rain Bird SiteControl can control two-wire decoders, satellite controllers or both for unmatched expandability and flexibility.

“Downes have chosen a SiteControl system with a Small Decoder Interface Unit (SDI) which can interface with up to 200 decoder addresses and activate up to 400 solenoids. With state-of-the-art ET-based scheduling, customised site graphics, multiple mapping options and the ability to ‘see’ the placement and operation of individual valves and sprinklers. The system makes controlling irrigation precise, fast and intuitive.”

“The system will be used in conjunction with Rain Bird LF1200 sprinklers which are designed for high uniformity so all container pots are evenly wet. In addition, the lower operating pressure prevents misting, decreases evaporation and minimizes wind drift.”

“SiteControl also features Rain Bird’s sophisticated Smart Weather™ technology which reacts to current weather conditions through logical sequential steps. It adapts irrigation rates to levels of rainfall and can even provide automatic frost protection which is so important in the nursery industry.”

“There is a large range of SiteControl units and accessories available so the system can be adapted to meet the needs of every imaginable landscape site. Site Control is suited for single site agricultural and turf applications.”

Construction has been completed on our massive shade house. It has 1km of upright posts and 4 acres of shade cloth. Its an amazing structure to see. Installation of the irrigation system is about to begin which I will go into more detail about in the next issue.