Smart garden watering
in Greener Homes on 16 May 2011
A new web guide will help straighten your irrigation
MELBOURNE has begun 2011 with record rainfall, but there’s no guarantee that the lush times will continue. The Bureau of Meteorology predicts that the La Niña conditions that brought the big wet will dissipate by wintertime.
By historical terms, the city’s dams are still low, and stage two water restrictions will remain at least until spring. That means householders still aren’t allowed to water their lawns from the mains. Gardens, however, can be watered by hand at any time, or every second day, at specified times, with manual and automatic irrigation systems. (You can find the full details about stage two restrictions on the Melbourne Water website.)
Geoff Connellan, from the University of Melbourne’s School of Land and Environment, says that just because we can water more often, doesn’t mean we should.
“The most common mistake people make in their gardens is to over-water, because they don’t understand how much water different plants need and how much moisture can be stored in the soil,” he says.
Together with Dr Jon Pearce and a team from the university, Mr Connellan has spent five years developing a free, online tool, called Smart Garden Watering, which helps you understand how to give your garden the right amount of water at the right time.
Using the website, you can calculate your water needs by entering all the details of your garden, including the location, size, slope and soil conditions, as well as the watering method and the types of plants and mulch.
The program draws on localised climate data and soil conditions, together with a database called the Burnley Plant Directory, which comprises over 1500 Australian and exotic plants.
Because it requires such detailed local data, the system is only available to residents in Melbourne and Geelong – for now, at least. “It does calculations for your postcode,” Mr Connellan says. “That’s important, because if you think of a garden in Sunbury and a garden in Olinda, they’re two totally different scenarios.”
The site is sprinkled with facts and features. It includes a Facebook application as well as maps, photos and forums that allow users to see other people’s gardens in their area, contact the gardeners and learn from each other’s experiences.
You can also plug in the details of your water tanks and see their likely storage levels throughout the year, based on the irrigation needs of the garden.
The results can be used not only to help you better understand your plants, but also to see what would happen if you re-designed your backyard. The website is interactive – you can toy with the settings and see how they affect your water consumption.
“It’s a sophisticated tool, but we’ve found that once people have become used to it, they are happy to play around with the options,” Mr Connellan says. “For example, if you choose drip irrigation or spray irrigation, or mulch or no mulch, you can see the consumption changing.
“That’s a very powerful graphical tool for a user. It encourages people to select efficient irrigation methods, and plants with low water needs.”
As a general tip, Mr Connellan recommends drip irrigation systems, underneath a layer of mulch of between 50 and 75 millimetres.
“Most people with plumbed watering systems can save about a third of the water they’re using, if they water wisely.”