The first step to reducing your greenhouse emissions is to do the maths.

Last year, Shaun Murray and his neighbours formed the Westside Carbon Rationing Action Group, aiming to reduce the eco-impact of their households. The first step was to estimate their greenhouse emissions.

The members plugged their energy use, flights, petrol purchases, and red meat and dairy consumption into a simple carbon footprint calculator (available on the Carbon Rationing Action Group website).

“It helps you to quantify and compare something that’s otherwise very hard to grasp,” Mr Murray says. “You get to understand the rough equivalencies – what it means if you switch to 100 per cent GreenPower or ride your bike instead of driving.”

The other benefit of these measures, he says, is that they help put our habits into perspective against others around the globe. Risk assessment company Maplecroft recently found that Australia has the world’s highest per capita carbon emissions from energy use, nearly twenty times more than India.

There are many other carbon footprint calculators available online that can help you decipher which aspects of your house and lifestyle have the most impact. The EPA’s Greenhouse Calculator is a comprehensive tool created by CSIRO (complete with teachers’ resources), while the Australian Conservation Foundation’s Eco-calculator takes account of water use and spending habits, as well as energy consumption.

Meanwhile, Mr Murray has reduced his carbon footprint to less than one-tenth of what it was. “I think that for a lot of people, it’s possible to make massive reductions in emissions,” he says.

Jeff Angel, executive director of the Total Environment Centre, agrees. “Do as much as you can by reducing your energy consumption and buying GreenPower,” he says. “After all those steps, you can make yourself carbon neutral by buying good offsets.”

Last year, the Total Environment Centre (together with Choice and the Institute for Sustainable Futures) founded Carbon Offset Watch, an independent ranking of Australian offset providers. “We set it up because there was serious public confusion about carbon offsets and major doubts about their veracity, accreditation and transparency,” Mr Angel says.

So which offsets will truly reduce your footprint? According to Carbon Offset Watch, the most effective projects change the underlying activities that create greenhouse gases. They include energy efficiency schemes, renewable energy funds, waste prevention and the protection of existing forests.

“The longer you have to wait for the carbon offset to mature, the greater chance risk that it may not eventuate – like tree planting,” Mr Angel says. “But if you are helping to pay for energy efficiency, those benefits are immediate when the new technology is put in.”

Climate Friendly was rated the best among the 20 offset providers that took part in the survey.

But there’s another catch. Under the Federal Government’s proposed emissions trading legislation, if an individual cuts their carbon footprint there’s no corresponding cut to the national target. Any voluntary cuts you make will just permit someone else to pollute more.

“Unless voluntary carbon abatement is ‘additional’ to the CPRS target, it becomes a feel-good exercise – it simply gives the big polluters an easier task,” Mr Angel says.

Carbon Offset Watch believes that although carbon offsetting is worthwhile, its future is in doubt if the flaw remains. “We’re campaigning for the Rudd government to solve the problem,” Mr Angel says. “The next two months will determine the success of the campaign.”

Gardens can thrive despite the drought.

It’s never too late to ready your garden for summer, says Anna Thirkell-Johnston, from Bulleen Art and Garden nursery, “but you’ve got to get onto it as soon as you can.” On October 15, she’s hosting a seminar on drought-proofing your backyard.

A number of tactics have begun to seep into common knowledge. Water tanks offer some independence from the mains: the larger the capacity, the better. Recycling greywater also boosts your supply, but it requires careful research and implementation.

When it comes to watering, it’s best to use a drip irrigation system and cover your garden beds with about ten centimetres of mulch – both steps will reduce evaporation and wastage.

But above all, Ms Thirkell-Johnston says, it’s important that people understand that soil is their biggest water storage device. “Organic matter is like a sponge in the soil,” she says. “Soils that have high organic matter hold a heck of a lot more water than those that don’t.”

She recommends gardeners build up their soil by adding compost and mulch to create humus – that’s the rich, dark and fertile soil that absorbs extra water. Moisture retention products such as crystals and wetting agents can be effective, she adds, but only if used correctly. Most people tend to use them too much.

On plant selection, Ms Thirkell-Johnston says there’s no substitute for study – search plant encyclopaedias or Google to find out what conditions suit the plant you’re considering.

Cam Wilson from Forest Edge Permaculture says a garden can be water-smart and productive. “A well-mulched backyard garden uses about one-fifth the water that a market gardener needs to grow the same amount of food.”

He recommends digging basins and trenches (about thirty centimetres deep) on the upper side of trees and shrubs. “If it’s been hot and dry, the soil doesn’t receive water very well. When you have a downpour, it rushes off the surface of your property,” he says. “The basins will intercept the runoff and hold the water, giving it time to infiltrate the soil.”

To avoid your yard “looking like a motocross track”, fill the trenches with mulch. “A tree-lopper can often drop off quite a large load of chips for $80 or $100.”

Drought-solutions can be attractive features. For a recent project, Mr Wilson created a dry creek bed, feeding from a shed downpipe. “It’s got disguised infiltration basins on the way down to water fruit trees, and they overflow into a frog-pond.”

He says it’s also crucial to shelter your garden beds from the hot western sun and from dry north winds. Try growing a grape on a trellis to the west – its deciduous leaves will offer summer shade.

To the north, he suggests planting a windbreak. “It reduces evaporation by a huge amount. I often recommend planting an Acacia hedge, which can be chopped back hard after summer to allow winter light. The prunings make an excellent mulch under fruit trees.”

Forming new habits is the key to cutting household waste.

Australians end up throwing out one in every five bags of groceries we buy, according to the website Food Wise. But food waste isn’t the only problem. The Ethical Consumer Group says we each consume about 165 kilograms of packaging a year and only half is recycled.

Hugh Butcher is trying to ditch that excess baggage. He was one of over a dozen Melbournians who recently took part in the Ethical Consumer Group’s weeklong, zero-waste trial (you can find details, tips and blogs on the organisation’s website).

Mr Butcher’s main tactic was to adhere as closely as he could to the waste hierarchy: avoid first, then reuse, recycle and last of all, dispose. That meant buying products in bulk and carting reusable containers whenever he went shopping. “Common foods that I eat, like pasta and nuts, I now buy in bulk – not pre-packaged. It’s my new standard practice.”

Environmental consultant Jenny Henty says a group effort is the perfect way to begin to cut your household waste. “When you’re starting off, it’s really good to have like-minded people who are trying to do the same thing.”

She argues that food wastage is a critical issue. “A huge amount of water and energy goes into producing the food. And then, if it decomposes at the tip, it generates methane, which is a very powerful greenhouse gas.”

To avoid spoilage, Ms Henty recommends planning meals, shopping with a list and buying only what you need. When you throw food away, make sure it goes into the compost.

As for packaging, we can cut back by switching to reusable bags and containers. “I use cloth bags for my fresh bread and I’ve got net bags for things like beans and peas,” Ms Henty says. She buys her dry goods in bulk, takes her own containers to the butcher and chooses cardboard containers rather than plastic wrapping.

But at chain supermarkets, that can be tricky. “You’ve got to change your shopping list,” she says. “You need to buy basics and cook at home.” Try shopping at markets, health food stores or supermarkets that sell goods in bulk (including cleaning products).

That might sound overwhelming, but it needn’t be so, if you take one item on at a time. “Step-by-step, you get into new habits that are no extra work,” Ms Henty says. “And if you reduce your supermarket buying, you can actually save a lot of money. When I cut out a lot of stuff I used to buy, I realised the food was better and I ended up happier as a result.”

At the end of his zero-waste week, Mr Butcher had only a few things in his rubbish bin – mainly wrappers from products he’d bought previously. “It was amazing what I got my waste down to,” he says. “I thought I was in for a massive shock, but it wasn’t as hard as I thought it would be.”

Green roofs and walls are slowly taking root.

A small number of city roofs and walls are sprouting lush foliage, and they’re attracting lots of attention. “Everybody is getting excited by them. I think it’s time to rethink city-wide design,” says Green Roofs Australia vice president, Ben Nicholson. His organisation is holding its annual conference at Melbourne University’s Burnley campus from September 23 to 25.

Mr Nicholson says although green roofs are an old technique, the modern systems were developed in Germany just three decades ago. Plants grow in lightweight soils over waterproof and root-repellent layers on the roof. They can range from extensive (inaccessible and low-maintenance) to intensive (abundant and high-maintenance, more like a roof garden).

Either way, they act as a sponge for stormwater, reduce urban heat radiation and boost biodiversity. They can also double the lifespan of roofing materials and reduce the need for heating and air-conditioning indoors.

That’s an enticing list, but so far in Australia, green roofs are only gradually moving into commercial and residential use. Mr Nicholson warns against putting on “green bling” that won’t stand the test of time. “There’s a lot of research to be done to establish which species will thrive locally over the long term.”

The other big catch is the cost of retrofitting on existing homes. Mr Nicholson says that an extensive green roof can weigh four times the load-bearing capacity of most roofs. “So before you’ve even started the retrofit, there can be huge costs in getting the building ready to host a green roof. It’s much easier to design a new home with a green roof. Our rooftops could then be sites for urban agriculture or habitat creation – as well as improving the view.”

Sydneysider Jock Gammon’s business, Junglefy, is working on a green roof for the Melbourne City Council. He estimates that an extensive green roof on a new home will cost between $180 and $220 per square metre. There’s a lot to keep in mind, including the roof capacity, plant selection and rainwater runoff arrangements. “Do the consultation and designs at the beginning of your building project,” he advises.

If you’re dedicated to gardening on high, but you’re not planning to build from scratch, then a green wall is the best bet.

Junglefy sells a range of vertical garden products, including ecoVert, a self-contained system that will help you grow herbs and veggies up the wall. It starts at $625, plus an optional mains or solar-powered watering system. The plants shoot from pockets of coconut fibres, not soil, and feed from organic fertilisers. “It’s designed for apartment dwellers and people with small courtyards who hadn’t previously grown things,” Mr Gammon says.

For a lower-tech food-producing wall, try espalier fruit trees. With pruning and training, you can grow the trees in flat patterns against a trellis or fence – it’s a tried and tested method, in use since at least the Middle Ages.

Greywater can wet your garden no matter the weather, but you must use it with care.

With another dry summer predicted, gardeners will soon need all the moisture they can get. Diverting your greywater can seem like a simple solution, but Helen Tuton from Sustainable Gardening Australia warns that it’s not so straightforward. “The long term effects of greywater on soil health aren’t known,” she says.

Greywater is the used water from your shower and bath, bathroom basin and laundry (not the kitchen or toilet). Collection systems range all the way from buckets to the big bucks.

No matter how you catch it, Ms Tuton says one thing is crystal clear. “Greywater and edible plants just don’t mix. A lot of fats, oils and salts come out of greywater and just sit in the soil.”

Chemicals, harmful bacteria and other residues in our recycled water damage the good bacteria and fungi that live in healthy soil. “I always recommend that people turn their greywater off over autumn and winter,” Ms Tuton says. “The soil needs a chance to be flushed out with rainwater.”

There are two kinds of greywater: untreated and treated. You’ll need to hire a licensed plumber either way, because both will require alterations to your sewer pipes.

Brent Papadopoulos from Sustainable Plumbing Solutions says that for public health reasons, untreated greywater isn’t allowed to see the light of day. “It must be transferred out to your garden through sub-surface irrigation. It must not pool anywhere and it must be used within 24 hours.”

An untreated diverter system costs between $700 and $2500. “They need regular checking and filter cleaning by the homeowner, otherwise they get blocked,” Mr Papadopoulos says. “Some systems might need attention twice a week. It just depends on the family: what they put down the drain and how hairy they are.”

Treatment systems are much more expensive – from $5,000 to $12,000 – and they require a permit from your local council. On the plus side, however, they’re eligible for a $500 Federal Government rebate and they produce much more versatile water.

“They harvest the same greywater but then they treat it and clean it up to a class-A standard,” Mr Papadopoulos says. “It can be stored and used in the home to flush toilets, wash clothes and also for above-ground irrigation like the good old-fashioned pop-up sprinklers.”

If you’re planning on gathering greywater, Ms Tuton recommends switching cleaning products, especially in the laundry. It’s important to buy products low in sodium and phosphorous. Washing detergents marked NP are phosphorous free, but for full information on different products, refer to independent testers Lanfax Laboratories.

According to Ms Tuton, there’s another puddle for greywater gardeners to avoid. “We’re finding that people are drowning their plants. They’re killing them with love,” she says. “Just because the water’s there, doesn’t mean you need to use it on the garden.”