Waste from suburban green bins across Melbourne is being reused as mulch on vineyards in central Victoria — with results showing more vibrant grape growth and reduced chemical use.
Hew and Diana Richards began planting their vineyard, Midhill, in Romsey, north of Melbourne 30 years ago.
The winery co-owners are hosting part of the trial, reusing waste from Melburnians’ green bins, to help bolster wine supply.
“Those sorts of things all help to create a healthier environment for the vineyard and reduce the chemicals that you might otherwise put on,” Mr Richards said.
“You can certainly see a difference in the foliage. When the vines are up and growing, the foliage, compared with the control group, is much more vigorous. It looks better, healthier.”
Diana and Hew Richards began planting their vineyard 30 years ago. (ABC Rural: Jane McNaughton)
Mr Richards said the grapes’ flavours and mineral composition had also improved.
“That would impact on the quality of the wine,” Mr Richards said.
“[However] we haven’t made wine specifically from this trial plot at this point, but it’s been added into the pick.”
The Richards grow predominantly pinot noir and chardonnay grapes. (ABC Rural: Laurissa Smith)
Kerbside waste to wine These are the results of six years of multiple trials in partnership with Sustainability Victoria and Melbourne Water at the cost of about $30,000, with the aim of creating a circular economy.
Melbourne Water’s sustainable agriculture facilitator, Karen Thomas, has been conducting trials across greater Melbourne’s farming areas from Woodend, Kinglake and the Mornington Peninsula to Phillip Island for a number of years.
“The green waste that you collect around your garden gets picked up and then it goes off, gets sorted and then it gets windrowed and composted to Australian standards and then it’s available for reuse,” she said.
“Private businesses, landscapers and local councils buy it back to use in playgrounds, garden beds and obviously farmers can ring up and purchase it.
“Please don’t contaminate your kerbside green waste because this is getting reused on farms.”
Mulch from green bins is being used in the trials. (ABC News: Hugh Sando)
So far, the trials have found that using recycled organic mulch during spring has led to healthier vines and fewer weeds.
Ms Thomas said that was due to the mulch creating an ideal temperature for the plants as the months warmed.
“What we’re finding so far is that the compost and mulch helps warm the soil in the spring and has a cooling affect in the summer months,” she said.
“We get an evening out of the temperatures, water saving and weed suppression.”
Vineyards often rely on herbicides. (Supplied: All Saints Estate )
Ms Thomas said when she started looking at some of these trials a few years ago, many vineyards wanted to stop relying on herbicides.
“[They wanted] ways to move away from those labour-intensive and less environmentally friendly treatments,” she said.
“[Instead] using urban green waste as a closed loop system in terms of taking waste away from households and reusing and repurposing it out on farms.”
Karen Thomas helped test the organic mulch to see how effective it was at encouraging vine growth. (ABC Rural: Jane McNaughton)
Worth the cost?Ms Thomas said the main challenge of the mulch was that it initially did not encourage additional vine or grape growth.
So, this year they have also been trialling adding manure to the mulch to make it worth the cost to producers.
“They were [previously] low in nitrogen,” Ms Thomas said.
“We want high nitrogen in the products as that will lead to a yield increase, which then leads to more money, which then offsets the cost of purchasing the product.”
Erica Winter has been investigating the physiology of vineyards for 25 years and is the research lead in the trials.
She said using mulch as a water-saving tool had been trialled before, but this was the first trial looking at soil temperature sustainability in cool-climate vineyards.
“We had an 18 per cent yield increase [in colder months], which is very good,” she said.
“[Also] a 5 per cent increase when the mulch didn’t have enough nitrogen.
“So, we’re aiming [for] a 10 per cent yield increase, reliably, as that would offset the cost of the mulch.”
Erica Winter has a PhD in plant physiology. (ABC Rural: Jane McNaughton)
‘Rewarding’ lessonsThe Midhill winery co-owners Hew and Diana Richards, who have been involved in various trials over the years, said they always found them worthwhile.
“We find it very interesting and rewarding to see what the results of the trial are,” Ms Richards said.
“Our knowledge increases greatly and your decision making, the day to day work in the vineyard, benefits I think.”
Midhill Winery has taken part in various trials to improve plant growth and farm sustainability. (ABC Rural: Jane McNaughton)
They had also been involved in trials that tested the benefits of dung beetles as well as organic fertilisers.
“The results are saying there is quite a good nutrient value to adding these as well,” Ms Richards said.
“All the quality of the fruit seems to be a little bit better.”
She said the biggest test off the back of the latest trial will be whether it was cost-effective.
“Small increments in grape quality may not be compensated for by what we may need to pay for the compost to be put out.”