How To Protect Plants From Frost: A Guide For Savvy Gardeners

06/10/2021 Rob Walter

Learn how to protect your plants from frost in the UK using William James' expert tips. Keep your crops safe during winter weather with our easy guide. Read on for more.

It's that time of year again: the weather is getting colder, and we're all beginning to think about how we protect plants from frost. Fail to do so, and you may end up with some very sad-looking plants come springtime!

Horticultural garden fleece and plant jackets will most certainly keep your plants toasty this year, but there are plenty of other options to try too.

Luckily, our gardening experts at William James have come together to share their top tricks and tips to protect plants from frost this winter.

What is Frost & How is it Formed?

Frost is simply a deposit of white crystals on the ground or other surfaces, formed when water vapour in the air changes directly to ice.

The freezing point of water varies depending on how much contamination there is, but generally speaking, water freezes at 0 Celsius.

The key thing about frost is that the colder it gets, the more damaging it can be. Plants will start to feel the impact of a freezing night and need protection; at lower temperatures, the damage increases exponentially.

It's essential to protect plants from colder temperatures in winter because the damage caused can be irreparable.

When Does Frost Occur in the UK?

Typically speaking, frost occurs between October and March in the UK. However, any time the temperature drops below freezing point, and there's a wind chill factor involved, you should protect your plants from frost.

The north of the UK tends to get colder weather than the South, which means gardeners in the North often have more of a job on their hands when it comes to protecting plants from frost!

What Causes a Cold Snap?

A cold snap is an abrupt drop in temperature which lasts for two or three days, typically between October and March. These occur due to large pockets of cool air moving across the UK from the north - these are known as a Polar vortex.

In addition to this, cold air drifts over the UK at night from the North Sea and can cause a sudden drop in temperature.

Therefore, it's vital to take steps to protect your plants in cold weather, especially tender and young plants.

How Does Frost Damage Plants?

Frost is a plant's worst enemy as it causes irreparable changes - both physical and chemical. Plants are made up of cells filled with watery sap that circulates nutrients around the plant.

When these cells freeze, they can rupture and burst, causing permanent damage to your plants' cell walls.

This results in what's known as 'frost burn', which causes browned or blackened leaves on both evergreens and deciduous plants. 

Another obvious result of unprotected plants being exposed to freezing temperatures overnight will be dead or discoloured foliage, but that's not the end of the story.

If left for too long, your plants could also suffer root damage or death, leading to further problems in the future.

Taking the time to protect plants from frost damage as part of your winter gardening jobs will prevent these symptoms and ensure you have healthy flowerbeds come springtime!

What Plants Need Protection from Frost?

So which plants need protection from frost? Well, some require more than others (known as frost tender plants).

For example, berry bushes and trees need extra protection from winter weather which can cause damage to their blossoms.

You'll also want to protect delicate flowers such as Camellias, Cyclamen, Azaleas and Hellebores. Even a small amount of frost damage in the early months of spring can mean no blooms for your garden come summer.

Winter vegetables like potatoes, broad beans and carrots can be protected with fleece tunnels and horticultural garden fleece.

Tender plants, young seedlings and any plants that are in pots are all vulnerable to frost damage and should be protected if possible.

How to Protect Plants from Frost in the UK

Protecting plants from frost is one of the top jobs if you're gardening in October. There are many different ways to protect your garden plants from freezing temperatures over winter, depending on the type of plant you look after and how much damage your plants can sustain.

Here are our tips for doing just that…

Cover the Soil With a Thick Layer of Mulch

The first step is ensuring that the soil around any plant roots doesn't freeze - freezing soil creates expansive pockets of water, which drain energy and nutrients away from vulnerable root systems causing permanent damage.

This isn't usually a problem for plants in small pots, but for larger plants, you'll need to protect the soil from freezing by covering it with a thick layer of mulch - this will help insulate the root system and ground.

If you have a greenhouse or glasshouse, protect your plants from frost by making sure that at least ten centimetres of warm air is above the plant.

Be sure to protect the mulch from being blown away by heavy winds, so secure it in place with stones or plant pots.

Use Horticultural Fleece or Plant Jackets

In an outdoor garden, this can be achieved using horticultural fleece or plastic sheeting - make sure to secure it properly with pegs and use enough layers so that no light penetrates through the plant.

Where possible, protect your plants from frost at night by bringing them inside or covering any outdoor pots - even something as simple as a sheet of thick cardboard will protect the leaves overnight.

If your garden is susceptible to heavy bouts of frost, protect against it by covering up vulnerable shrubs and trees with sheets or blankets overnight; this will prevent them from sustaining any severe damage. Do not wrap the sheet all the way around a tree or shrub, as it can cause damage to new growth that may have cracked.

Protecting Indoor House Plants from Frost

If your house is particularly cold, protect against light frost on windowsills and other surfaces with sheets of plastic or even newspapers - this will prevent ice from forming between panes of glass.

This will protect your plants from frost damage and prevent condensation in the winter, which can cause dampness.

How to Protect Trees from Frost

Like plants, trees are also susceptible to frost damage - the most common being 'frost cracks' or 'sun scalds'.

Frost cracks occur when the sap in a tree's trunk freezes and expands, causing the bark to split. Sun scalds happen when the sun heats the bark during the day, causing it to expand. When the temperature drops at night, the bark contracts and can crack.

To protect trees from frost damage, you should:

• Water them well before a cold snap to help them withstand the frost
• Wrap the trunks of young trees in horticultural fleece or bubble wrap to insulate them
• Cover the roots with a thick layer of mulch
• Place a stake next to any leaning trees to support them if they should crack under the weight of the frost.

How Should I Protect Fruit Trees in Winter?

Fruit trees need extra care throughout winter to ensure they remain healthy during the colder months. This is particularly important for those who have recently planted their tree as it's still getting used to its new environment.

If your garden is particularly frost-prone, protect trees and plants against heavy frosts by placing a thick layer of mulch over exposed roots and stems before covering them with straw, leaves or bark chips.

Be sure to protect the mulch from being blown away by heavy winds, so secure it in place with stones or plant pots.

What are the Most Common Plant Frost Protectors?

You have a few options if you want to protect your plants from frost, depending on the types of plants you grow and the type of garden you have.

A balcony garden with potted plants needs a different approach from a low-lying vegetable garden where plants are grown directly in the ground.

Does Netting Protect Plants from Frost?

Some types of garden netting can help to protect plants from frost damage by creating a barrier between the plant and the cold air, like our windbreak netting.

These nets have a close mesh, which offers protection to plants from cold winter winds. Netting with a large mesh, however, will not protect against frost, as the cold air can still pass through the netting.

Make sure to secure the netting in place, so it doesn't blow away in strong winds, and cover any gaps with straw or leaves to insulate your plants further.

When using netting to protect plants from frost, make sure to remove it once the risk of frost has passed, as it can restrict the plant's growth. You should take extra care when using netting to protect younger tender plants. Using a cold frame can help to create a warmer environment for these plants to grow in.

What if My Garden Doesn't Experience Frost?

If you live in an area where it never gets cold enough to cause any damage to your plants, that doesn't mean that you still shouldn't protect them from the cold.

Even if temperatures don't drop low enough for frost to form, they can still cause damage to plants by slowing down their growth and making them more vulnerable to disease.

Again, our windbreak netting is ideal for protecting your garden from colder conditions. It's lightweight and flexible, so it can be used to create a protective barrier against cold winds without blocking out too much light.

Summary: Our Top Plants Frost Protection Tips

So, there you have it - our top tips to protect plants from frost this winter. Just before you go, here are some key takeaways that we've covered in this post!

• Protect vulnerable plant areas with thick layers of mulch. Be sure to protect your mulch from heavy winds by securing it in place with stones or garden fleece.
• Ensure that any protective measures you use, such as sheeting or fleece jackets, are anchored into the ground to protect against wind.
• Cover fruit trees with thick layers of mulch and protect the mulched areas from heavy winds by securing them in place.
• Bring vulnerable plants inside either in your shed, greenhouse or your windowsill.

When it comes to protecting your plants from frost, follow these simple steps for the best results! And don't forget to grab yourself our quality garden fleeces to provide your plants with the best plant frost protection possible.

FAQs