What happens in winter to fruit and citrus trees

Tropical fruit trees, and citrus trees in particular, absolutely need to enter a resting phase during the cold season. They go into dormancy in order to regain their strength for good growth, flowering and fruiting in the summer months. Growth of the above-ground parts stops, although the roots continue to grow underground.

If you don't give your Key Lime tree, for example, this rest, it won't die immediately, but it will wither, lose vigor, flowers and fruit will become rarer, and your plant will be less resistant to disease and parasites. A bit like a sleep-deprived human!

Where to put my frost-sensitive tropical fruit trees during winter ?

In order to rest properly, frost-sensitive fruit trees such as the Toad Tree or citrus trees, like the Bergamot orange tree, need a temperature no higher than 7 or 8°C, and air that's not too dry, so they don't dehydrate. Therefore, our hot, dry interiors are not suitable for them; a cool, frost-free room is preferable, but one that is still bright enough for them to continue photosynthesizing. This room must also be ventilated, to avoid excessive humidity stagnation, which would rot the plant.

Orangeries were invented for this purpose, but an unheated veranda, or a frost-free greenhouse, or even a bright garage, will do just fine.

When should I bring in my frost-sensitive fruit trees ?

Plants can obviously be spotted by falling temperatures, but even more so by shortening daylight periods, to know that it's time to put them to rest.

As long as frosts are not to be feared, you can leave them outside, preferably sheltered from the wind that accentuates cold sensations, for example sheltered by a south-facing wall that can both protect them and prolong a stored warmth from a winter sun. Then, as soon as frost sets in, they can return to their winter resting place, only to emerge again in spring. Above all, be careful with species that have just sprouted, such as Lime berry, or your young plants, as it's easy to be surprised.

How to water citrus and fruit trees during winter ?

Water sparingly. First of all, you need to avoid excess humidity, both in the substrate and in the surrounding air, at the risk of rotting your fruit tree. If the room has no natural or artificial ventilation, you'll need to air the surrounding air regularly. Water the substrate only when it is thoroughly dry. You can stick your finger into the potting soil to gauge its moisture content; you can also weigh the pot: a heavy pot means the substrate is still quite moist. There are also hygrometry testers that you can stick into the substrate and read off its moisture content.

But water anyway! You mustn't forget to water your fruit and citrus trees over the winter. They don't need to dehydrate, but they do need a minimum supply of water!

In conclusion, tropical fruit and citrus trees need heat, but not too much (no frost, but no more than 8°C), and need water, but not too much (no dehydration, no rotting)!