News ID: 241382
Published: 0808 GMT April 14, 2019

Climate change affecting vegetable crops in Canberra region for backyard gardeners, farmers alike

Climate change affecting vegetable crops in Canberra region for backyard gardeners, farmers alike

Autumn is upon in Australia, which means it is time to plant their sweet peas, broad beans and lettuce so they can establish well before the frosts. Or is it?

Across Australia backyard gardeners use time-tested planting schedules to ensure a good yield, but no place is more inextricably linked to the seasons than Canberra, wrote.

Newcomers to the city will be quickly told that Anzac Day signals the time to turn on the heater and not to even bother planting tomatoes until after Melbourne Cup.

But as the capital last month recorded the hottest March ever, the unseasonably warm days have also had an effect on how and when to plant.

"Climate change has most definitely affected the timing of those established rules of when you plant and when you don't plant," Dr. Steven Crimp, a climate applications scientist from the Australian National University said.

Among many changes Crimp noted, an increase in frosts in September and October, a lack of steady rainfall, and warmer minimum and maximum temperatures had contributed to battered copies of the Canberra Gardener rule book being thrown off shelves.

"The warmer temperatures have people continuing to plant well into autumn and winter, because the soil temperatures are warm enough to sustain the crops," Crimp said.

Of course, it was not just keen backyard gardeners who had noticed the effect of erratic weather events.

"We've had a lot of evaporation and not enough rain," Geoff Foster from Jerrabatt Gully Organics in Bungendore, just outside of Canberra, said.

But for Foster, who grows and sells a range of produce through a subscription-style weekly delivery service, the weather was more than just an annoying, unpredictable frustration.

The heatwave the region experienced in January saw a lot of Foster's crop fail, particularly his tomatoes.

"In spite of trying to plant more, we're getting less per plant."

Chris Fowler, who operates Bywong Garlic, ran into a similar problem last winter.

"When I reflect on last winter and the winter before, I remember walking around in short sleeves for most of the time. I don't call that a cold winter," Fowler said.

“So I have brought planting forward from April into March. I've also brought my late season crop forward."

Fowler had observed the slow change in his soil over a number of years.

"When I first came here we had a 100mm of soil moisture depth most of the year, except for the hottest part of the summer. Now I would say it's 25-30mm for most of the year," he said.

"Because I don't run stock, I used to mowed these paddocks. I haven't done that now for five years because the grass doesn't grow as well.

"It is dry, there's no soil moisture depth."

Ruth Gaha-Morris is the vice president of the Southern Harvest Association, an organization that represents local growers and runs a weekly farmers market in Bungendore.

"Most of them are struggling," she said.

Gaha-Morris said the producers she represented and spoke to all shared a few common experiences over the last few years.

"One of the biggest issues is the erratic weather patterns that we're having, and extreme rain rather than regular rain," she explained.

"When it's dry they're searching for water and when it's wet they're trying to save their crops and their animals from water damage that happens with large storms.

In Bywong just a few weeks ago, Fowler experienced that kind of rain on his garlic crop.

"I had 31 millimeters in 10 minutes, which flooded the place, but when the water had gone you'd never have known it had rained," he said.

"Because you don't get the gentle soaking rain over a period of time you don't get that soil moisture.


Is better irrigation the solution?


Gaha-Morris said almost every producer she talked to said they needed increased or different irrigation.

"There's a huge pressure on already depleted water sources," she said.

"Even olives are needing to be irrigated.

But while irrigation was one of the solutions, Crimp explained it came at a cost.

Aside from the infrastructure required, there was the cost of water, especially for those who did not have access to bore water.

"The rainfall we rely on to get a crop from a seedling to maturity [is not] sufficient," Crimp said.

"So we are more reliant on irrigating crops, which increases the cost of growing things.

"Unless we have permanent water sources, it's not hugely sustainable."

If the prolonged heat, dry soil and dumpings of rain were not enough for growers to deal with, unseasonable frosts were also destroying their crops.

"Managing heat stress and frost has become more of a challenge," Crimp, who has conducted research into the impact of changing frost frequency, explained.

"There used to be clear windows where the frost would occur. Now we have heatwaves and frost events which are occurring and intersecting, which makes it difficult to sustain crops.

While changing frost frequency had already had an impact on wheat production nationally, locally, fruits like cherries and apples, which could usually be grown successfully during cold weather, were suffering.

"There are more extreme frosts, but less chilling time, and there needs to be that chill for the plants to fruit the following year," Gaha-Morris said.

"Every year the bar gets moved. We can't rely on what the weather's going to do anymore."

If even experienced farmers and community growers are having trouble with unpredictable weather patterns, what does that mean for the humble backyard gardener?

"I'd encourage people to keep a record of their temperature and rainfall and go back and review that regularly," Crimp suggested.

"If you're seeing a trend in that information, respond to that trend by adjusting your planting next year.

Gaha-Morris urged gardeners to concentrate on building soil fertility.

"The more fertile your soil is, the more water it's going to hold," she said.

"Also, make sure gardens are shaded, that they're caring for pollinators, and avoid pesticides that kill pollinators."

But Gaha-Morris said, if growing your own produce was not a possibility, people should continue to shop locally to support farmers.

"Buy seasonal and local and build a relationship with them," Gaha-Morris added.

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