Larry Hodgson has published thousands of articles and 65 books over the course of his career, in both French and English. His son, Mathieu, has made it his mission to make his father’s writings available to the public. This article was originally published in the newspaper Le soleil on December 5, 1987.
You might think that, well wrapped up in our homes, sheltered from the snow and drying winds, houseplants would not suffer from winter. However, it’s quite the opposite. Most of them are tropical plants from regions where the daylight hours do not change from one season to the next and where the humidity remains constant.
How difficult it is for them to adapt to our winters! The result is often a loss of foliage, reduced growth or, on the contrary, excessive and unhealthy growth, and sometimes the loss of some more sensitive plants. If your plants aren’t looking as good as usual, here are some ways to help them get back on their feet:
1. Increase the Length of the Day
Hang a fluorescent or LED light over the plant and turn it on from late afternoon until 8:00 p.m. every day. On cloudy days, leave it on all day. While these lights may not fully meet the needs of your plants, in combination with even low levels of natural light, they do them a world of good.
2. Watch the Watering
Some plants grow more slowly in winter and require less water, but at the same time, the dry air in our homes and the heating dry out the soil more quickly. In many cases, therefore, you will need to water more often in winter than in summer. The key is to check the soil daily and water as needed (i.e., as soon as the soil surface is dry), even if not at the same frequency as in the summer.
3. Reduce Fertilization
Plants that stop growing completely in winter (e.g., cacti) do not need any fertilizer during this period, while plants that are slow-growing will need to be fertilized at half or even a quarter of the normal concentration.
4. Increase Humidity
This is one of the most important factors. You should consider 50 percent humidity as the minimum level needed for growing plants. So keep your humidifier running (and, of course, full of water) and, in addition, group your plants together to create a more humid mini-environment.
5. Avoid Major Work
Cutting, repotting, pruning, etc., during the winter stimulate weak growth that will never look good. Therefore, only do major work in case of an accident. Wait until mid-February or March.
6. Put Your Plants in the Sunniest Window
Le soleil hivernal n’est pas assez fort pour endommager les plantes et, si vous avez le choix, une fenêtre au sud convient mieux que toute autre durant l’hiver, même pour les « plantes d’ombre ». Évitez, si possible, les fenêtres au nord à moins d’y ajouter un éclairage supplémentaire.
7. Beware of Insects
Some insects, especially the red spider mite, take advantage of the weakness of plants in winter to do damage. If new leaves turn yellow for no apparent reason, check your plant with a magnifying glass and treat with insecticidal soap if necessary.
8. Turn Down the Thermostat at Night
Tropical or not, indoor plants appreciate cool nights. Lowering the temperature to 15°-18°C at night does no harm and will often stimulate flowering in “difficult” plants.
9. Use Artificial Lighting
Artificial light kept on for 12 to 14 hours a day will induce the same growth and flowering as a well-lit window in the middle of summer. In this case, it’ll be necessary to water and fertilize as in summer, because your plants will remain in full growth.
10. Avoid Cold Windows
No part of a plant should touch cold windows directly, as it can freeze, especially at night.
By following these tips, you should be able to keep your houseplants in much better shape during the winter.
Winter, which is obviously milder here, is when we put some of the houseplants out to recover from being inside all year. They enjoy the rain for a while. I just do not leave them too exposed during frost.
I have a large light shelf and in the winter a have a rotation so that all of the plants spend time ont he shelf for a few days every so often. It works really well.