Keeping Your Houseplants Alive During Winter: A How-to Guide
Have you become a first-time plant parent or expanded your indoor forest during lockdown? Many more people staying (and working) from home during this pandemic have undoubtedly boosted the already successful indoor plant sales, with more of us reaping the benefits of luscious foliage. I enjoy taking care of my plants but understand that it can be tricky keeping them happy, especially during this time of the year.
In response to the decrease in temperatures, earlier sunsets and lower levels of humidity indoors in the Northern hemisphere, our plants may show the following signs associated with “dormancy:”
- • Reduction in plant growth
- • Leaf drop
- • Yellowing
- • Slower absorption of water
Dormancy, true dormancy and quiescence
Dormancy is often used as a general term to describe the characteristics mentioned above or decline in metabolic activity to conserve energy. Amongst horticultural experts and amateurs, confusion arises when classifying whether a plant is or isn’t dormant. Whether your plant is biologically “programmed” to undergo true dormancy or quiescence depends on its species and the environmental conditions it is best adapted to.
True dormancy occurs when some species, such as deciduous fruit trees (i.e. apple, apricot and cherry trees), undergo dormancy despite exposure to ideal growing conditions. While environmental conditions such as temperature, moisture and light levels can promote or inhibit this state, truly dormant species cannot switch from dormancy to active growth as autonomously as other species. I like to think of this as a plant going into “hibernation” or a “deep sleep” it cannot be easily woken up from during the colder seasons.
Species such as sub- and tropical fruit trees (i.e. citrus, banana and avocado trees) and most common houseplants (i.e. cheese, prayer and rubber plants) will enter quiescence as opposed to true dormancy. In this state, plants can adjust metabolic activity more readily in response to fluctuations between favourable and unfavourable conditions in the environment. I imagine this as “light sleep” to allow a plant to save energy when it is dark, dry and cold until conditions improve.
In summary, quiescence may explain why your houseplants look like they are dying in autumn but begin thriving again in spring. At the moment, yours may be appearing sadder than usual because they are native to environments far more tropical than inside UK households.
Preparing your houseplants for autumn and winter
There is a lot of scientific jargon in this blog post, but I can assure you that you do not need extensive scientific knowledge to enjoy your houseplants. I have prepared a list below with care tips I follow.
- • Water sparingly, because your houseplants are more prone to overwatering when their growth rates have slowed down. Do not water if the potting mix feels wet. If in doubt, I would wait a few days until giving them a drink.
For chronic over- or under-waterers, I recommend investing in a moisture metre for plants, priced from £4. With this device, you can probe the potting mix to measure how much water it is holding.
- • Increase light exposure by moving plants closer to an east-, west- or south-facing window. Sunlight from a south-facing window will suit plants that require more intense lighting conditions. Check out this post if you would like to learn more about lighting and window orientation.
If I have any free time I would like to dedicate to my plants, I clean my windows and gently wipe the dust off the leaves to maximise the light my plants absorb.
Some plant lovers use grow lights, which simulate natural sunlight. However, I believe that this is entirely optional for beginners because all of my plants survived last year’s Mancunian winter in a dark and cold bedroom without grow lights.
- • Reduce or completely omit fertiliser. When your plants are not actively growing, they will require fewer nutrients. Therefore, I recommend taking a break from fertilising until spring. However, if you notice a plant going through an intense growth spurt, you could add heavily diluted liquid fertiliser when watering it.
- • Reduce exposure to cold drafts and Most common houseplants will tolerate the temperature you maintain inside your home. However, they may wilt or crisp when exposed to extreme and frequently fluctuating temperatures.
- • Increase humidity by moving plants into the bathroom, placing them in a terrarium, making a humidity tray (placing your plant on pebbles in a tray or plate with water), air-drying laundry nearby, or introducing a humidifier.
My most important piece of advice is to monitor your plants when adjusting care and placement. Check up on them once in a while. Have your plants been growing much more rapidly in a particular location? Are you noticing significant changes in the colour of their foliage? I highly recommend watching plant advice videos and using image-search to diagnose the cause of any superficial symptoms.
If you notice a decline in your plants’ health this autumn and winter season, I hope my tips can help you or encourage you to care for a plant. In my experience, caring for plants is a learned skill, which requires assertiveness, experimentation and practice. Most people, myself included, are not born with a green thumb and have accidentally killed at least one plant. Sometimes it just happens!