Preparing garden, potted and balcony plants for winter – what to keep in mind

Frost, snow and ice-cold wind – winter is around the corner. This means that potted, garden and balcony plants need to be prepared for the cold winter months. But when is the best time to start? A good indication is of course the temperature itself. In some countries, this could already have become critical for some plants by October. Despite warm temperatures during the day, you particularly need to watch out for cool temperatures at night. And some good old farming wisdom can help with preparing your plants for winter, too. For example, according to an old German saying, if the autumn is warm and pleasant, a harsh winter is coming. We explain which plants you need to prepare for cold temperatures and take you through the steps of how to do it.

Winter-hardy plants

If you take a look at your garden during winter, you will notice some plants can withstand the cold winter months. This is because they are winter-hardy plants. These plants are characterised by the fact that they survive unscathed when exposed to temperatures below zero degrees Celsius for some time. Some examples include various different types of grass, climbing plants and a number of garden herbs. A few exotic plants, such as particular cactus species and palm trees, as well as some balcony and potted plants, can also brave the cold temperatures. Generally speaking, sensitive plants should be moved to their overwintering location before the first night frost. More robust plants can stay outside as long as the temperature doesn’t drop below zero degrees Celsius. Truly winter-hardy plants can survive the whole winter outside but they should still be protected from extreme weather. The best way to work out exactly how winter-hardy your plants are is by looking at the care instructions of each plant. You can find some examples of winter-hardy plants from different regions in our slider.

The materials you will need to prepare your garden for winter

Both winter-hardy garden plants and potted and balcony plants should be prepared for cold temperatures. We have made a list of everything you will need:

• Secateurs or shrub shears, such as EasyPrune or Isio
• Straw or pine needles
• Garden fleece, bubble wrap or jute sacking cloth
• Wooden board or polystyrene sheeting

If the onset of winter is close, it is time to get going. To get your plants and flowers through the winter, there are four important steps to take.

Preparing your garden for winter. Step 1: Remove dead flowers and leaves

The first step when properly preparing your balcony and potted plants for the winter is to fully remove old and dead leaves and flowers. Using secateurs, battery-powered secateurs or battery-powered shrub shears makes light work of the task. It also reduces the risk of damaging the plants, which can occur if leaves are ripped off. Why is this step important? Removing the leaves means that the plant uses less of its valuable energy. It also means that pests are deprived of sources of food. Keep in mind, however, that you should not prune the flowers and leaves too heavily. This would damage some plants immediately before the onset of winter and it might even cause long term damage. You can find tips about correct autumn pruning and more ideas for a winter-hardy garden here.

Preparing your garden for winter. Step 2: Cover and protect plants

If you have winter-hardy plants in pots or balcony boxes that cannot be taken inside, they need to be thoroughly protected from frost. Pots in particular transfer damaging cold to the soil and roots. This is due to their material properties. This is why it we recommend that both plants and pots are wrapped up warm for the winter if they are kept outside. The easiest things to use as an insulating layer against the cold are bubble wrap or fleece. Better yet, you can use matting made of natural materials such as coconut fibre or sheep’s wool. We would also recommend the use of aluminium foil for certain plants. It is particularly well-suited for protecting saplings of oak, linden, maple and fruit trees, for example. Simply put a few layers of aluminium foil around the trunk and this protects the thin bark from frost damage – particularly from splitting.

To provide the best possible protection from ground frost, you should also place pots on a wooden board or polystyrene sheet. For additional winter protection, you can cover the plant soil with a thin layer of fir branches, brushwood or straw (also a good tip for bedding plants). But make sure that enough air can get to the soil through this covering. Another example of where less is more! If your potted plants are small trees or shrubs, then you should also cover each of these with jute sacking or a special fleece cover that is tied together at the trunk. This protects sensitive branches from damage and helps ensure that evergreen plants are not dried out by the wind. This additional protection is a particularly good idea for Mediterranean plants and flowers, such as hardy olive trees or palms.

Preparing your garden for winter. Step 3: Find the right overwintering location

Finding the right overwintering location for plants and pots is just as important as sufficient protection. Non-hardy plants, such as citrus plants, should be kept indoors in a frost-free environment. A light and cold room, such as a stairwell or bedroom, will provide a good overwintering location. The important thing is that it is not overheated. Cellars and garages are alternative options, provided there is enough daylight. Important: Air the room regularly!

Conservatories and greenhouses are also good options. These locations are the perfect place for evergreen plants to spend the winter. Provided you have cleaned the glass panes before putting the plants in there, oleander, laurels and the like can receive enough light in these locations, even during the winter. Another advantage of overwintering locations that are made of mostly glass is the constant climate. Temperatures between five and ten degrees are ideal and will get the plants safely through the winter. To prevent possible frost, we recommend using a simple greenhouse heating system and/or a frost monitor.

There is no written rule for the ideal winter protection for hardy balcony and potted plants. But it is a good idea to protect them from the wind under a canopy or put them against the warm house wall. Burying the pot in the soil can also help. This is because the soil in a free-standing pot freezes more quickly than when it is buried in the earth.

Preparing your garden for winter. Step 4: Don’t forget to water your plants

By autumn, you may already have started to water your plants less. Even so, you should not completely stop watering them in winter. You should water the potted plants spending the winter in your house as often as is needed to prevent them from drying out. Plants staying outside should be watered when the daily temperature is at its highest and on frost-free days. Ensure that the water only goes on the soil and not on the leaves and branches. This way, you avoid frost damage. The amount of water the plant will need depends on the plant species and size of the pot. If a potted plant has dead leaves in winter, this is often a sign of water deficiency. No fertiliser is needed during the calm winter months.

Care advice to help selected garden, potted and balcony plants through the winter

Each plant requires its own tailored care package for winter. Some plants like it light, some like it dark. Some need to be watered regularly, some only very occasionally. You see, there is no ‘one size fits all’ solution. We have put together some example images which show you how you can care for certain plants during the winter months.