How to overwinter your plants
Plants go through different cycles throughout the year. Spring and summer mean an explosion of growth, activity, lushness, and plant frenzy. However, autumn and winter are resting periods when plant growth usually slows down.
Plants use light as a form of energy to produce food and grow. This process is known as photosynthesis. As light levels lower in the winter months and days shorten, plants cannot obtain as much energy relative to the summer season and as a result, the rate of photosynthesis slows down. In some cases, it completely stops. With winter also come lower temperatures, which further reduces the rate of photosynthesis and the growth of the plant.
Water also plays a part in the process of photosynthesis. Since plants are photosynthesizing (phew what a word!) at a much lower rate during winter, they do not require as much water or as much fertilizer during this period.
This being said, as houseplant parents we are totally in control of how much light, water and heat our indoor potted plants get year-round. Thanks to modern technology we can now recreate similar conditions indoors in winter to those which naturally occur in summer, and therefore continue to care for our plants in winter as we would in summer.
We can use artificial plant lighting to increase and prolong light levels in the room, or else simply help our plants by placing them closer to the window or light source.
At Plantae, we’ve put together a small guide to help our fellow plant enthusiasts to take care of their houseplants in winter. Whether you are trying to match winter conditions to summer ones or letting your houseplants go through the cycle, there are a few pointers to bear in mind. We hope you find them useful!
1. Make sure plant leaves aren’t touching the window glass
Cold temperatures outside will make the window glass cold, and any plants or leaves placed against it may get frostbite and die. You can consider removing your plants from the windowsill all together. This is a judgement call and basically depends on how insulated your windows are, how often you open them, what kind of aspect the room is, and how hardy the plants are.
It also depends on the thermal conductivity of the material you have your plants on. For example, if your windowsill is ceramic, it will conduct heat away from your plant faster than if it was wood. So, while you may not have any plants touching the window, consider also what they’re sitting on and even the type of pots they're in.
2. Revise your watering routine
As we mentioned above, a slower photosynthesis rate means the plant will require less water. When temperatures get colder, there will also be less evaporation and the soil may take twice as long to dry. Overly damp soil could cause root rot. You may need to reduce watering frequency and water only when the soil is almost completely dry.
The amount of light in the room will always determine the amount of water being used up by the plants as it is absorbed during photosynthesis. If you are using artificial lighting, you can continue to water regularly. Always use the temperature and light levels in your home as a guide, as well as feeling the soil of your plants to know when and when not to water.
If you're using tap water to water your plants, make sure it isn't very cold. In winter, water from the cold tap tends to be really cold, and it could damage the roots of your plants!
3. Repot only if necessary
It’s not like repotting plants is forbidden in winter, but it is true that it’s better to avoid repotting unless necessary. The plant may not have the necessary energy to grow new roots or adjust into the new soil and pot.
4. Fertilize only if there is active growth
For the same reason that plants will require less water, they will also need less food. Since they may not be growing quite as fast, they may not be able to use up the feed you’re giving them, and therefore it may be wasted and overfertilizing may damage the plant.
To the contrary, you can continue to fertilize your plants so long as there is active growth, which will only happen if you are providing adequate lighting.
5. Some plants may go into dormancy or some leaves may turn yellow and drop
Some plants, like bulbs for example, lose all their foliage and go into dormancy during autumn and winter unless exposed to the right conditions (i.e. enough light and warmth). Some other plants may shed some leaves, and that’s completely normal and ok. They will bounce back in the spring!
PS In case you were wondering, two popular bulbous houseplants that go dormant in winter are Caladiums and Oxalis Triangularis aka false shamrock plant. While not bulbs, Cacti and succulents also usually go dormant in winter.
6. Keep your plants away from radiators
Heat from radiators will make the air in the room a lot drier than usual and some plants, especially those humidity loving calatheas, monsteras, alocasias, and in general all tropical plants will have a hard time coping with low humidity levels. You may even witness a crispy leaf tip festival!
To be safe, keep all your plants (tropical and non-tropical) away from radiators as much as possible, and if you are truly dedicated, get a humidifier to bring humidity levels in the room back up.
7. Use artificial lights for dark spaces
Certain spots in the room may get decent light in the summer, but less so in the winter. Purchase a couple of LED full spectrum artificial lights to help your plants survive. Remember, no plant can live in the dark, even if they are low light plants!
You can also help your plants by moving them closer to the light source or placing them in the sunniest room in the house.
8. Continue to check for pests
No matter the season, plants can still be effected by pests. Perform weekly checks and continue to dust the leaves of your plants to dislodge any potential bugs or eggs!
We hope you found these tips useful and that their application helps your plants thrive throughout autumn and winter!