How to protect your plants in winter?

For us, winter means hot chocolate, snowball fights and reruns of Mommy Missed the Plane. But for our plants, it's far less cheerful. The dreary season, with its cool temperatures and heavy rainfall, can be fatal for them. Here's how to protect your favorite plants from the cold, frost and damp.

All plants have a hardiness temperature, a temperature below which they won't survive. For tropical species, the hardiness temperature is around 10°C. This is well above normal winter temperatures in Europe. This is why, in our latitudes, Monstera, Alocasia and Calathea are grown as houseplants. Conversely, some rhizomatous plants, perennial flowers and trees are more resistant to the cold. Asters and bletilla striata hyacinth orchid bletilla striata, for example, can withstand temperatures as low as 15 degrees below zero.

In theory, all plants should be protected. In practice, the list depends on where you live. If you live in Provence, you can leave the less chilly species to fend for themselves. But in Alsace and the North, most varieties need help to overcome cold and frost.

The drop in the thermometer isn't the only danger plants face between November and March. Precipitation and humidity can also be a death sentence. This is the case for agaves. They can withstand temperatures as low as -20°C, provided they are kept dry.

Don't wait until the last minute. Sometimes, a night of frost is enough to decimate beds and rock gardens. To avoid tragedy, we recommend anticipating and protecting your plants before the cold sets in. What's more, acting in advance limits the thermal shock to plants. They can get used to their new environment more easily.

At Monstera, we're a bit like Nicolas the gardener meets Évelyne Dhéliat. We know the hardiness temperature of different species and the weather trends. So we're working to warn you when it's time to protect your plants from the cold. This feature will be available from 2023.

There are many ways to protect fragile plants from frost and cold in winter. Depending on hardiness, planting method (in pots or in the ground) and your means, choose the one that suits you best.

South of the Loire, cacti and succulents spend most of the year outdoors. When the temperature drops, you can bring them inside your home. Reserve a well-exposed spot for them, but away from direct sunlight. On a shelf just behind a curtained bay window or opposite an east-facing window, they'll enjoy maximum light without danger. While they're indoors, water them sparingly. In general, a monthly watering is sufficient.

Other less hardy plants, such as Mediterranean shrubs, can't withstand the rigors of winter or indoor heating. Ideally, they should be kept in a light, unheated shelter. If you have a veranda or greenhouse, put your Lemon tree, oleanders and bougainvilleas there before the frost sets in. Grouping plants together also helps them to keep each other warm. But don't crowd them too much either. Your protected plants must not touch each other to prevent disease.

Not everyone has a garage with a window or a garden shed in which to store their potted plants when the mercury drops. And this solution doesn't apply to open-ground crops either... In these cases, alternative methods help your plantings to last through the winter.

Start by protecting the roots by mulching the base with organic matter. A ten-centimeter layer of dead leaves, hay, grass clippings or straw is an excellent barrier against frost and cold. As it decomposes, it becomes an excellent fertilizer.

For your roses, in addition to mulching, use mounding. Behind this somewhat barbaric name lies a simple gesture: bring a mound of soil to the base of the plant, up to the height of the first branches. Roses aren't the only ones to appreciate this kind of attention. In the vegetable garden, mound up peas, beans and potatoes.

Foliage and trunks must also be protected from the cold weather. Wrap them in a winter cover. If you're worried about a very cold spell, don't hesitate to make several layers and wrap the pot as well. But covering vegetables and small perennials can quickly prove tedious. To spare your efforts, opt for a wintering tunnel, which is easier to install. Have you decided to make your own winterizing fabric? Don't use tarpaulin or plastic film. Impervious to air and water, the material will suffocate your plant. Whatever protection you choose, always ensure that air circulates inside.

Another tip for warming potted plants is to raise the height of the planter. The stone or concrete floor of our terraces retains the cold and causes the temperature of the substrate to drop. By placing cardboard, bubble wrap or wedges under your container, you create a layer of insulation and gain a few degrees. Finally, we advise you to place your planters close to a wall. Protected from wind and heavy rain, your plants will also benefit from the warmth given off by your home.

Dahlias, gladioli and hyacinths require radical treatment. Plants must be uprooted and bulbs stored in a dry, ventilated, frost-free place. You can store them in your cellar, garage or even laundry room, provided there are no windows. Light triggers the germination process.

The first thing to do to combat excess humidity is to reduce watering. During winter, plants need less water, and rain is generally more than enough.

But if the skies are too generous, a few precautions should be taken to protect your plants. Remove the cups so that water doesn't stagnate in them. It could freeze or rot the roots.

Prevention is the key to combating excess water. When planting, work and amend the soil in your garden toimprove drainage. For species that are more sensitive to humidity, select a spot at the top of a slope or near plants that absorb excess water during showers.

Now that your plants are sheltered, don't forget about them until spring.

Check soil moisture regularly and water when the soil is dry. To prevent the water from freezing, do so in the morning and, if possible, on a sunny day. Take the opportunity to air the winter fleece for a few minutes.

If you've brought moisture-loving plants like papyrus and begonias into your home, mist their foliage regularly. The dry air of our heated homes doesn't suit them very well. On the other hand, there's no need to mist the leaves of cacti and succulents. (To learn how to mist like a pro, read our article Should houseplants be misted?).

Finally, be patient. Don't remove all protective covers as soon as the first rays of March sunshine appear. Frosts may still occur. Once the last cold snaps have passed, remove the winter covers and tarpaulins, put the pots back in their places and bring your plants out into the fresh air. Once again, there's no need to rush. After three months in the greenhouse or in your living room, they will need time to adapt to light and temperature.