As the cold weather sets in, it's important to know how to protect plants from frost, as tender and young plants in particular can be wiped out by a sudden cold snap.
There are many quick ways you can protect more vulnerable plants and it's definitely better to be safe than sorry – there is nothing more devastating than seeing the beautiful plants you have lovingly nurtured destroyed seemingly overnight by a visit from Jack Frost.
Unless you live in a warm zone, it is likely that some of the ornamental plants and crops you have included in your garden ideas will be in need of some protection, so read on to find out how you can help their survival through the colder months.
How to protect plants from frost – which plants to protect
Not all plants in your backyard will need protection from the frost, but there are certain categories that will. These include:
- Young seedlings and new growth
- Tender perennials
- Half-hardy varieties
- Tropical and subtropical plants such as palms and banana plants
Signs of frost damage include blackened, distorted or limp growth and the leaves turning green on evergreen plants and shrubs.
If in any doubt, research the conditions and hardiness of specific plants. Err on the side of caution and include frost protection in your winter garden ideas if cold weather is forecast in your state or area.
In terms of vegetable crops, there are some that actually benefit from a dose of frost and can taste better afterwards. 'There are some veg crops that are frost tolerant, if not frost resistant,' explains Nicole Burke, author of Rooted Garden (opens in new tab).
If you live in a colder zone, it is therefore worth learning how to grow kale and other frost tolerant vegetable crops.
1. Bring potted plants indoors
There are many quick ways for how to protect plants from frost, and among the easiest is to bring potted plants indoors, especially tender container plants.
Potted plants are more susceptible to frost damage because they don't have the insulated benefits of of those planted in the ground.
Use a conservatory, garden room, garage, porch or frost-free greenhouse to overwinter potted plants – not somewhere that is too warm.
2. Add a layer of mulch on garden beds
'Apply dry mulch, such as chipped bark or straw around borderline-hardy plants, such as agapanthus, phygelius (cape fuchsia), hedychium and the architectural melianthus to protect the crown,' advises plant expert Sarah Raven (opens in new tab).
You could also use leaf mold or piles of leaves to add some extra protection on garden beds and provide a barrier against the cold.
Find out how to make leaf mulch to protect tender and emerging plants.
3. Cover plants with fleece
You may wonder how to protect plants from frost when they are planted in the ground? One method – which is useful for larger garden plants and shrubs – is to cover them with horticultural fleece. You could use blankets or bubble wrap, too, to create a protective cover. These Amazon plant covers (opens in new tab) come highly recommended by reviewers.
Place several stakes around your plants and then cover these with the chosen material to create a tent-like structure. Weigh down the corners to prevent the coverings from blowing away in the night and remove the covers during the day.
You can use this method for plants that require winter protection, such as agapanthus, cordyline and tree ferns.
'Fleece is very effective, but if you prefer something less obtrusive, a circle of wire netting filled with bracken or leaves will keep the cold at bay, too' advises Sarah Raven.
4. Place tender plants in a sheltered spot
The mantra 'right plant, right place' is relevant when considering how to protect plants from frost.
'Always plant half hardy and frost tender plants in a sheltered position, preferably near a south or west-facing wall, which will absorb heat during the day and radiate it at night,' advise the experts at Jacksons Nurseries (opens in new tab).
'Eliminating the wind chill factor can substantially reduce the amount of frost damage incurred,' they add.
Other sheltered positions will include next to fences, under large evergreen trees for gardens, under the protection of pergola ideas or in patio or courtyard areas, as long as these also receive plenty of sunshine.
While a sunny, sheltered spot is ideal for many tender plants, do not place early-flowering plants, such as magnolias and camellias, so that they are exposed to the morning sun. 'The rapid thawing of frozen buds can result in blackening and bud drop,' advises Guy Barter, horticultural expert at the RHS (opens in new tab).
5. Lift and store tender perennials
Tender perennials that have bloomed and died down can be lifted to protect them from frost.
Store the roots, bulbs, tubers and corms in a cool but frost-free place, such as a potting shed or greenhouse. There are lots of mini greenhouses to shop at Amazon (opens in new tab), should you only have a few tender perennials to protect.
6. Protect tender plants with a cloche
If you're wondering how to protect plants from frost in the vegetable patch, then a cloche is one of the best methods. A cloche can be used to protect seedlings and smaller plants from frost.
Cloches are bell-shaped covers made from glass or plastic that can be placed over the plants. You can buy cloches or even make your own out of recycled objects. They also sell a range of cloches on Amazon (opens in new tab).
'Cut-off large plastic bottles or milk containers can be turned into homemade cloches to embed into the soil around small plants and seedlings to provide protection,' advise the experts at Jackson Nurseries.
Remove them during the day to allow the plants to benefit from the warmth and energy of the sun.
Cloches are ideal for use with young vegetable crops that are sown in fall, such as broad beans, spinach, scallions or spring onions and asparagus.
7. Move plants into a cold frame
Young hardy annuals that are sown in fall may also benefit from some protection from frost.
Place them in the shelter of a cold frame over winter, although ensure they have good ventilation on warmer days.
You could make your old cold frame if you don't already have one, advise the experts at Jacksons Nurseries.
To make your own temporary cold frame:
- Bend slender, metal rods into loops – you could use wire coat hangars for this
- Insert the ends of the metal loops into the ground either side of a row of crops or plants
- Lay a sheet of clear plastic over the frame and secure it in place to protect the plants below
8. Water plants in the morning
You probably wouldn't think that your routine for watering plants could make a difference when considering how to protect plants from frost – but in fact it can help support any protective measures you take.
It is best to water plants in the morning during winter and when there is a risk of frost, because wet soil actually absorbs heat during the day and has an insulating effect.
9. Wrap containers
If you are unable to move containers indoors as a method for how to protect plants from frost, then try to protect them from the elements outdoors by placing the pots in sheltered areas, and where possible grouped together for added protection against the cold and wind.
Container plants are more likely to suffer from their roots freezing. To prevent this, 'wrap the containers with bubble wrap from Amazon (opens in new tab) or straw, or bury the pots in the ground with just the rim showing, to benefit from the insulating properties of the ground,' advise the RHS experts.
Also raise containers using pot feet or by resting them on bricks to allow water to drain away more easily, and prevent plants sitting in icy water.
10. Choose the right plants for your backyard
Rather than trying to protect plants that are not suited to the climate of your backyard, instead choose those that are reliably hardy in the zone where you live. This will prevent the disappointment of losing plants when they aren't adequately protected.
Many evergreen shrubs and plants are fairly hardy. Plants will have a hardiness rating ranging from fully hardy – able to withstand temperatures of 0-10 °F (-18 -12 °C) – to frost tender, which might not survive being exposed to temperatures below 40-50 °F (4-10 °C).
While this might limit to some extent the plants or crops you can include in your garden, there will still be plenty of options suitable to you hardiness zone.
What can I cover my plants with to prevent frost?
There are many materials that you can use to cover plants with to prevent frost.
You can find many permeable horticultural fleeces and frost protection products on the market, but can also use materials that you can find around the house – just make sure they are lightweight, breathable and insulating.
Options to use include:
- Bubble wrap
- Blankets, bed sheets, towels
- Leaves or other organic materials
What temperature should I cover my plants for frost?
The temperature that you should cover your plants from frost to protect them will depend on the individual plants and the conditions and position in which they are planted.
Frost occurs in temperatures below 32°F (0°C) so this is the point at which you need to be protecting plants in winter.
Most plants will need protecting from temperatures of 30°F (-2°C) or lower, but frost tender specimens should be protected before temperatures dip this low.
Can I use plastic bags to cover plants from frost?
It is not advisable to use plastic bags to cover plants from frost. This is because plastic can damage your plants if it makes contact with foliage, as it holds water against the plant and causes more damage from freezing.
It also isn't a very insulating material, nor is it an eco-friendly or a sustainable option, so look for alternatives when deciding how to protect plants from frost.
Rachel is senior content editor, and writes and commissions gardening content for homesandgardens.com, Homes & Gardens magazine, and its sister titles Period Living Magazine and Country Homes & Interiors. She has written for lifestyle magazines for many years, with a particular focus on gardening, historic houses and arts and crafts, but started out her journalism career in BBC radio, where she enjoyed reporting on and writing programme scripts for all manner of stories. Rachel then moved into regional lifestyle magazines, where the topics she wrote about, and people she interviewed, were as varied and eclectic as they were on radio. Always harboring a passion for homes and gardens, she jumped at the opportunity to work on The English Home and The English Garden magazines for a number of years, before joining the Period Living team, then the wider Homes & Gardens team, specializing in gardens.
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