Protecting Plants from Cold Weather and Frost
Protecting Plants from Cold Weather and Frost
Cold temperatures and frost can damage tender plants and can even cause plant death if the plant cells become irreparably damaged. Repeated freezing and then thawing is particularly damaging for plants as is very rapid thawing.
Newly planted plants, young plants and plants in pots and containers are more susceptible to the cold than mature plants or hardy plants in the ground. Plants in pots, even if they are normally hardy in the ground can be more susceptible to cold. when planted in containers. This is because the roots are susceptible to freezing as they are only protected by a small amount of compost and surface of the pot is exposed to the cold air.
By taking some simple steps you can protect your plants ensuring they flourish for years to come. Follow our handy guide for some top tips.
Move houseplants inside that have been outside for the summer
Your houseplants may have been outside whilst the weather was warm for their summer holidays, however they will start to suffer and will eventually die when the temperature drops too low. October is usually the month to bring your houseplants back inside the home or into a protected greenhouse.
Move potted container plants closer to the house
The temperatures near the walls of your house are warmer than the surrounding air so bring any pots that are moveable closer to the house. Not only will they be more accessible and you will be able to see them without venturing too far it will provide additional protection. A south facing wall is best.
Don't expose plants to early morning sun in winter
Place your plants away from early morning sun. If plants warm up too quickly after being frozen the flowers and young growth can be killed.
Wrap pots and containers in bubble wrap
Secure bubble wrap around the pots and containers to help prevent the soil in the pot from freezing.
Water your plants before frosts are expected
Water your plants if they require it a couple of days before a frost is forecast. Moist soil retains more heat than dry soil. However do not water when the temperature is below freezing as plants cannot process this water and it can result in frost heave, where the pressure in the frozen ground lifts the plants out of the soil.
Do not feed plants high nitrogen fertiliser late in the year
Avoid feeding your plants late in the year with fertiliser that contains high amounts of nitrogen. Nitrogen encourages green shoots and leaves. This soft growth will be very susceptible to frost and will turn black and die off when temperatures go below freezing.
Leave the previous seasons growth on tender plants
Leave the previous season growth on your tender plants rather than cutting it off. This adds a layer of protection and if the leaves do get frosted only the part you would have cut off will be affected.
Cover plants with horticultural fleece
Horticultural fleece is a lightweight fabric that is used to cover frost tender plants to protect them from the cold. It is breathable, lets light through and is permeable. Fleece can protect against cold, strong winds, dehydration, hail, impact rain, dirt, pests and birds. It is available in packs and rolls of different lengths and can also be purchased by the metre. Horticultural fleece is available in different thicknesses, the thicker the fleece the lower the temperature it protects against. Standard fleece bought by the metre is usually the thinnest around 17 gsm. If you have purchased a lighter weight fleece you can always use more than one layer over your plants.
Place the fleece over your plants in the evening before the temperature drops below zero. Don't forget to remove the fleece in the morning when the temperature rises above freezing to avoid damaging your plants and to allow them as much light as possible.
For convenience you can also buy fleece jackets. These are placed over your plants and then the drawstring is tightened at the bottom to tuck the plant into its fleece coat.
30 gsm fleece can protect down to -5 /-6 degrees celsius. 80 gms fleece can protect down to -16 degrees celsius.
Fleece also provides an organic pest protection method for fruit and vegetables. It can also help protect against carrot fly and cabbage root fly. It can also be used to cover the soil to prewarm the ground in early spring.
Put plants in a cold frame
Cold Frames are basically low greenhouses and are ideal protection for smaller plants from cold and wet in winter. You can buy cold frames online, at your local garden centre or you can make your own out of bricks or blocks with a pane of glass or a window over the top.
Mulch plants that are in the ground
Mulching helps hold in moisture and warmth in the soil. Straw, decorative bark, pine needles and leaves are popular materials for mulch. Apply at a depth of 5 to 7.5 cm (2 to 3 inches) to be effective. Mulch can help prevent the roots in the ground from freezing and can be used on conifers, evergreens and tender perennials. Not all plants though appreciate a deep mulch.
Dig up and store tender tubers and bulbs
Tender tubers and bulbs can be dug up and stored in damp compost and placed in a shed or greenhouse to overwinter. Dahlias tubers are probably the most common tuber that is overwintered this way. As soon as the first frost has passed and the foliage starts to turn black dig up the Dahlia tuber to store.
Lift tender perennials
Dig up tender perennials such as Canna, Pelargoniums and non-hardy Fuchsias before the first frosts and store in a light but frost free place.
Protect fruit with straw
Fruit, including strawberries can be protected by placing straw around the plants.
Grow plants in raised beds
The higher the ground the less likely it is to be affected by frost, as cold settles in deeper pockets. Raised beds are therefore slightly warmer than the surrounding soil. They are also easier to cover with fleece or a cloche.
