If you’re new to gardening, or have relocated to an area that experiences winter frosts, the topic of frost-proofing plants may be new to you.  If that’s the case, we’re here to help and this article should bring some clarity.  However, please remember that if we haven’t covered everything you’d like to know, just pop in to your nearest Blackwood’s.  Our knowledgeable team is ready to assist.

The first few frosts of winter aren’t usually heavy frosts.  However, plants that are frost tender (unable to tolerate frost and liable to die if exposed to it) can be damaged by even light frosts.  It’s a good idea to make a plan to protect your frost tender plants when frosts are forecast.  Not all plants require frost protection. Hardy, cold weather garden plants like perennials, trees and shrubs are all plants that usually withstand frost. There are also many types of flowering annuals, vegetables and herbs that will manage frost, too.  It’s best that if you’re unsure, chat to us for advice.

The most important plants to protect are plants like tropicals, tender potted plants, some types of annual flowers and frost sensitive vegetables.  Read the labels of your plants when you purchase them.  Most will provide an indication if a plant is frost hardy or tender.

Interestingly, many homegrown vegetables actually taste better and have more flavour after a frost fall. Cold hardy vegetables like peas, lettuce, spinach and other salad greens, carrots, broccoli, cauliflower, cabbage, kale and Brussels sprouts, won’t be harmed by a light frost.

So let’s take a look at what can be done if it looks like overnight conditions will include frost.

Step 1 is to water your plants well that morning.  Water in the soil will heat up in the sun during the day.  This helps to keep your plants warm overnight and provides a little protection against the cold frost.


Step 2 is to provide some sort of frost protection for your frost sensitive plants overnight to prevent frost damage. The best protection is covering your plants is with commercial frost guard, frost bags or some kind of lightweight plant covering material.  Frost protection fabrics hold in the heat that rises from the soil, keeping plants warm.


Do not use plastic for the purpose of frost protection.  If done incorrectly, plastic over your plants can prove more harmful.  Plastic is not breathable and therefore traps in moisture.  This moisture then freezes, causing harm to the plant.  If you must use plastic rather than cloth, use stakes or some other kind of support to make frost “tents” over your plants. Take care to ensure the plastic isn’t touching any part of the plant or leaves.

It’s important that you don’t cover your plants too early in the day, or they will overheat.  The best time would be after the sun is off the garden in the late afternoon, or right before sunset.  When covering your plants, ensure that you drape your frost cover fabric over them and allow it to lie loosely on the ground.  Don’t wrap up your plant with the fabric, tying it around the base of the plant.  The idea is to create an area that will trap in warmer air around the plant.  It’s a good idea to secure the frost cover with a brick or two in case of wind.


Step 3 is to ensure that the following morning, you remove the frost cover early in the morning before the plants get too warm.

Step 4 The last step in frost protection during winter is to consider is laying a layer of mulch around shrubs, trees and perennials to help maintain a more even soil temperature. Not all of these plants will require mulching, so chat to us to help ascertain where mulch will be beneficial.  When laying mulch, take care not to place it too close to the base of trees or stems of plants.  While mulch is available at all Blackwood’s stores, other materials are commonly used, such as straw, hay, pine needles and bark or wood chips. Just remember that when choosing winter mulch, ensure that there will be airflow to the plants below the mulch.