Guide to Protecting Plants from Frost in Australia

Frost can damage our plants in some parts of the country that get freezing nighttime temperatures.

Luckily, there is a range of ways to protect your frost-tender plants so they don’t suffer extensive damage or die.

Here are a few ways that you can protect your plants from frost damage in Australia.

Cover the soil with a thick layer of mulch

mulch around plant | Plant care

Mulching around your plants is a great way to protect their roots from freezing temperatures. The mulch acts like an insulation blanket on the soil to keep the soil warmer and can stop the ground from freezing.

Make sure that you lay the mulch thickly over the soil and around the base of your plants. Use a dense mulching material that won’t trap cold air close to the soil.

Use mini greenhouses to cover your frost-sensitive plants

mini greenhouse | Plant care

Depending on the size of the plants that you need to protect, mini greenhouses made from cut-off plastic bottles can work really well because they create a nice, warm environment around your tender plants.

For larger plants, you can purchase ready-made greenhouses from places like Bunnings that you can erect and place over tender plants to protect them from frost damage.

Once the weather warms up, you can dismantle these and store them in the garage until next winter.

Wrap your potted plants in bubble wrap or hessian 

bubble wrap frost protection | Plant care

Potted plants can easily be wrapped in bubble wrap or hessian to protect them from frost.

Make sure you wrap the entire pot to keep the soil warmer but don’t totally enclose the plant itself because it will still need good air circulation.

Once the danger of frost is over, take off the wrapping so that your plants don’t become overheated.

Use shade cloth to protect your plants

Make a shade cloth cover for your sensitive plants to protect them from frost. This is a good way to cover a group of plants that might be sensitive to frost damage.

All you need to do is create a structure over your plants using stakes or poles and then drape the shade cloth over this, making sure to secure it to the structure so that it doesn’t get blown off during heavy winds.

Cotton sheets can be used to cover your sensitive plants

frost protection | Plant care

You could do the same sort of thing using lightweight cotton sheets to cover your frost-sensitive plants. Just construct a frame over the plants and drape the sheet over this. 

Make sure that the sheets are fairly lightweight so that they still let air and light through to the plants. You might consider just covering the plants during the night and removing the sheet during the day once the temperature has risen again.

Even old net curtains can be used to cover your plants overnight and protect them from frost.

Grow frost-sensitive plants under tree canopies

If there are frost-sensitive plants that you simply must have in your garden, consider growing them under canopies of taller trees. The trees will protect the more sensitive plants growing under them.

Avoid adding nitrogen-rich fertiliser to sensitive plants in autumn

Young tender growth in plants can be more sensitive to frost damage. Therefore, you want to avoid promoting new growth in frost-tender plants.

To do this, don’t fertilise your plants from mid to late summer with a fertiliser high in nitrogen because this will stimulate new growth.

Spray your plants prior to the arrival of frost

Rose spray | Plant care

It’s a good idea to spray your plants with a seaweed solution such as Seasol prior to the arrival of frost. This helps to strengthen the cell walls of the plants and helps to protect them from frost damage.

You can also get a spray called Envy that will help to protect your frost-sensitive plants. This spray is made by AgroBest and is a frost protectant. It works by reducing moisture loss in plants so that they are less susceptible to frost damage.

Build a cold frame over low-growing plants

If you have low-growing plants in your garden that may be susceptible to frost damage, consider building a cold frame to protect them.

This can be made from a variety of materials such as timber to make the frame. Use this frame to support a sheet of glass so that light can still reach your plants but they’ll be protected from the cold moisture in the air.

For a really simple cold frame, you can just rest the glass panel on some small pots that you’ve placed around your sensitive plants.

Cover your delicate plants with a polytunnel

frost protection 1 | Plant care

Low polytunnels are also quite popular to cover plants that may be sensitive to frost. These are usually made from flexible piping that is shaped into a half-moon shape and covered with plastic sheeting.

Once you’ve made your polytunnels and protected your sensitive plants, these can be removed when the danger of frost is over and stored for use again the following winter.


Is there a spray to protect plants from frost?

There is a product called Envy made by AgroBest that can protect plants from light to medium frost. It can also reduce moisture loss by around 50%.

Can I use a tarp as a frost blanket?

In an emergency, you could use a tarp as a frost blanket but this is not recommended for permanent usage as moisture can get trapped underneath the tarp and cause more damage to your plants.

Photo of author

Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.


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