Heatwaves Are Becoming Too Extreme for Plants

By Selina Green

ABC Rural

Topic: Agricultural Crops

Thursday, June 4, 2026, at 6:29 am

Heatwaves in spring harm wheat flowers, causing big losses.

In short:

Heatwaves are getting worse and making it hard to grow food.

Very high temperatures are happening in summer and spring when wheat flowers.

What's next?

Scientists are working to find crops that can handle high heat, but more help is needed.

When Australia had record heatwaves, people, animals, and plants suffered.

The extreme heat destroyed crops and showed a growing problem for farmers.

Researchers warn that very high temperatures throughout the year threaten food security.

Anthony De leso manages a farm that grows many types of vegetables and herbs.

His farm was hit by three extreme heatwaves that hurt delicate crops.

Anthony De leso grows spring onions, parsley, coriander, and dill all year.

The last heatwave was the worst because it was very hot for many days.

It was like the last problem for many of our crops.

Our coriander stopped growing in the second heatwave.

We had to start over because it was easier than trying to save the existing crop.

Lost income from ruined crops and rising costs are hurting the farm's budget.

In the past, I would have said this is just something we have to deal with.

Coriander is a crop that is easily hurt by heat.

Since 2022, our costs have increased, making it harder to take losses.

We are discussing what to do differently, like growing other crops or using protected cropping.

More research is needed

Professor Owen Atkin says extreme temperatures 'break the biology' of plants.

Summer temperatures broke records in South Australia and New South Wales.

Temperatures were very high over many days in southern Australia.

Some areas recorded temperatures of 65 degrees Celsius at the soil surface.

Anything growing near the surface gets extremely hot.

Owen Atkin says heatwaves can hurt pollen and boil grapes on the vine.

Some regions and crops are more susceptible to heat damage, like wheat and grapes.

The Riverland and Mallee areas are at risk.

In SA, crops like grapes are easily hurt by heat.

Heat can boil berries on vines, affecting yield and wine quality.

Not just summer

Heatwaves can happen at other times of the year when temperatures are high.

Spring is a critical time for wheat flowering.

Crops like wheat, grapes, and almonds are more susceptible to heat damage.

Pollen is very sensitive to heat.

Heat can kill pollen, leading to reduced yields in wheat and other plants.

One day of heat can be enough to cause problems.

An unusual heatwave in September can reduce yields by 10 to 20 percent.

Heatwaves significantly impact crops like avocados.

There is an urgent need to adapt and find ways to grow and protect crops from extreme heat.

This includes better heatwave predictions and improved irrigation practices.

Gene editing and modification may also be used to make crops more heat-tolerant.

Testing heat-tolerant wheat

Research is underway across Australia and the world.

Dr Crystal Sweetman is leading a study to improve heat tolerance in wheat.

The study aims to improve yields of bread wheat during combined heat and drought conditions.

We are learning about the strategies plants use to deal with heat.

The study has found some promising results, with some wheat varieties able to protect themselves during extreme heat and drought.

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Thursday, June 4, 2026, at 6:29 am

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