Cold alert!

While the warm temperatures of the last few weeks have led us to believe that the risk of frost has passed, Mother Nature is preparing a little surprise for the coming nights when temperatures will be close to freezing.

Most of our vegetables and annuals are plants that originate from tropical climates and are therefore mostly sensitive to cold. With temperatures that fall below 10°C, fruiting of vegetable plants and flowering of annuals can be greatly affected, while temperatures below or near freezing can simply kill these plants.

Although it is advisable to move our plants to the garden only when the nights are above 10°C, sometimes the weather plays tricks on us, even when the season is already quite advanced.

If the solution for plants in pots is to simply bring them into the house, garage or shed, it is a little more complicated for plants that are already in the ground. For the latter, water them well before the temperature drops. This will protect the roots from the cold. Afterwards, shelter your plants with a floating canvas, a day veil, an old sheet, cardboard boxes or overturned pots. If you use the latter option, don't forget to make a hole for ventilation and to avoid condensation. It is not recommended to use plastic sheets as they are cold conductors. In case of cold weather, you can cover your plants with straw or dead leaves to give extra insulation. Also beware of strong winds which can affect the foliage of certain plants that are not adequately protected, even if they are sheltered by a building (e.g. climbing plants).

The floating fabric is an excellent tool to add to your gardener's kit: it not only protects against cold (by increasing the air temperature by 2 to 5°C under it), but also makes an excellent protection against insect pests for sensitive crops (e.g. cabbage, onions, leeks, etc.). It has the advantage that it allows sunlight and water to pass through, and therefore does not need to be removed from the crop.

Non-exhaustive list of cold-sensitive plants:

  • Begonias;
  • Palm trees;
  • Canna;
  • Petunias and other annuals;
  • Tomatoes;
  • Cucumbers;
  • Courgette and other courgettes;
  • Melons and other squashes;
  • Aubergines;
  • Chillies and peppers;
  • Beans;
  • Ground cherry;
  • All basilisks;
  • etc.