WINTER HOUSEPLANT CARE
10 Steps to Maintaining Healthy Plants
As autumn becomes winter, the once jewel-toned leaves of Maple and Acer trees fall to reveal the sturdy yet elegant architectural structures beneath.
It always seems as though the minute those leaves are gathered and added to our compost bins, mother nature begins to cool things down. Almost like she knows and allowed me time to do that.
Once done, soft, powdery crystals begin to fall. Icing our garden with undulating drifts of fresh snow, like icing on a cake. The depth of which will nicely insulate plant and tree roots from our frigid temperatures.
It may seem counterintuitive that cold snow would keep plant roots warm, but it does. A lot of things in nature are like that.
So, with everything outside asleep for the winter, what is a gardener to do?
Well, instead of giving in to the immediate urge to sit and start planning next year’s garden, I switch gears and remind myself that I can still play in the dirt with some proper winter houseplant care.
Not only do your indoor beauties need a little extra attention to get them safely through the winter, but caring for them can do a world of good for you too.
DOES WINTER HOUSEPLANT CARE HELP with SEASONAL AFFECTIVE DISORDER?
Winter houseplant care can have an up-lifting effect on our mental health in a number of key ways.
Particularly in severe winter climates, January tends to be the coldest month (Imagine living in a place where you can’t be outside for longer than five minutes or risk hypothermia).
But, even for those living in a temperate climate, cases of seasonal affective disorder dramatically increase.
Now, I’m not suggesting that you go out and buy every houseplant you can find to ward off the winter blues. There’s a little more to it than that.
But, maybe you’ll see a cute, little one at the grocery store. Or, maybe a friend or neighbor has one that you could ask to take a few cuttings from, to grow your own.
How can winter houseplant care brighten up the blues?
A 2015 study published by the Journal of Physiological Anthropology discovered a link between plants and feelings of wellness.
Stress levels that increase heart rate and blood pressure were shown to be greatly reduced when participants worked with plants versus non-plant related tasks.
This may prove to be related to our primordial connection to nature.
Just as when we exercise, or do other things that are good for us, our brains release endorphins (happiness hormones) as a reward for doing those things. How’s that for self-care motivation?
ARE INDOOR PLANTS AFFECTED by WINTER?
Our houseplants are biological entities just like we are. So, when something changes in their environment that isn’t necessarily good for them, they “react” to those changes. Signaling to us that something needs to be adjusted.
Some plants, like pothos and certain succulents, actually prefer it to be cooler in winter. As this aids in their transition into dormancy.
Tropicals, like orchids, African violets and alocasias, only experience partial dormancy. So, winter houseplant care for these beauties must include maintaining consistent humidity, warmth and light.
That may mean putting them in a small greenhouse for the winter (this is what I do).
Or move them to a room that still gets plenty of indirect light during the winter months, while spritzing them to maintain adequate humidity. We’ll touch on this in more detail in a moment.
DO INDOOR PLANTS GO DORMANT in WINTER?
Many mammal species go into hibernation for the winter. This is a common survival mechanism at a time when food and liquid water are in short supply. Heart rate, breathing and other bodily functions slow down in order to conserve energy.
Houseplants (which originally evolved outdoors) have adapted with a similar, seasonal mechanism called winter dormancy.
During which metabolic processes like growth, photosynthesis and nutrient absorption slow down. Even indoors, this adaptation is still triggered when the days grow shorter and light wanes.
How far into a dormant state houseplants go depends on the type of plant. Some only go into partial dormancy and continue to grow, albeit at a slower rate.
Other types may stop growing all together and may even drop their leaves. This doesn’t mean they’re dying. It’s simply a way to further conserve energy. Although dormant, they still need some good winter houseplant care.
DO YOU WATER DORMANT PLANTS in WINTER?
Because heaters are running more often in winter, causing inside air to be hot and dry, you might think that plants would need more water. But, not so.
Plants need water during their active growing periods to carry nutrients throughout and aid in photosynthesis and chlorophyll production.
But, because these processes are significantly slower in dormancy, they actually don’t require as much.
My winter houseplant care routine includes cutting the amount of water I give each plant by one-third to one-half. And mist them twice a day to maintain adequate humidity.
If you overwater during this stage of winter slumber, it could lead to root rot and the loss of your plant.
COMMON PROBLEMS with HOUSEPLANTS in WINTER
Overwatering is actually the most common issue growers experience with their indoor plants in winter. They just don’t realize it.
I get a lot of emails asking “Why are my houseplants dying? I’m watering and fertilizing them like I always do. I’m not doing anything different.”
Luckily, the answer is simple and easy to remedy. Part of effective winter houseplant care is just cutting back on everything you do in warmer months.
Unnecessary winter fertilizing is the second most common issue for those living in colder climates.
A plant’s metabolism slows way down in dormancy and therefore can not process fertilizer the way it can when it’s actively growing.
Fertilizing a plant when it can’t do anything with it, will kill it. Even those that only go partially dormant.
If you live closer to the equator, I would still suggest holding back on feeding in December and January. Days are still shorter and plants respond with slower activity.
THE BASICS of WINTER HOUSEPLANT CARE
From roughly March to September, especially when we open our windows and let in all that fresh air, nature provides a lot of the light, humidity and warmth that plants require in order to stay healthy.
In winter though, I’m not going to be opening my windows when it’s -30°C outside. So, I’ve found that keeping the following 10 points of winter houseplant care in mind, they’ll thrive. And in return, they’ll help you thrive too.
In the northern hemisphere, September marks the beginning of the sun’s slow descent toward the horizon. With the Earth turning on its axis, away from the center of our solar system.
Leaving us with shorter days and less light for our houseplants to maintain healthy dormancy. If you live in the southern hemisphere, these winter houseplant care tips will be useful starting in March.
In order for plants to adequately maintain their green color (chlorophyll), they still need a certain amount of sunlight.
Moving your plants (or mini greenhouse) to a west or south facing window, as the first part of your winter houseplant care regimen, will allow for enough indirect light exposure to prevent yellowing and potential leaf drop.
Indirect light is critical. As bright, direct sunlight amplified by glass window panes may scorch plant leaves and cause dehydration.
In regions closer to the poles, where days are even shorter and sometimes non-existent, grow lights are a literal life-saver.
There are several on the market that offer beneficial amounts of simulated sunlight for your plants and for you. Placing your plants 4-12” below the lights will yield maximum results.
Sitting with them for a few minutes each day will also allow you the opportunity to get some much-needed light exposure, vitamin D and the release of some of those happy hormones.
As the light changes through winter, I’m constantly moving my plants around to make sure they’re getting adequate light. Much to the chagrin of my husband who’s in charge of spritzing.
But, come spring, when all our plants are still green and start growing, he sees the method to my madness.
Since most houseplants are native to tropical regions, they prefer a temperature range from 12°C – 23°C (53°F – 75°F).
Just like we do, they prefer it warmer during the day and cooler at night. This mimics our biological (and often forgotten about) adaptations to outdoor environments.
Staying within this range is as easy as keeping an eye on the thermostat. Keeping your plants away from drafty or frosty windows, radiators and fireplaces will prevent their exposure to extreme temperature changes that may cause permanent damage.
Below 12°C, the moisture inside your plants can freeze and result in irreversible tissue damage. Above 23°C, moisture will rapidly evaporate and dehydrate plants. High temperatures can also scorch foliage beyond the ability to recover.
I keep my sensitive tropicals in a mini greenhouse and spritz them every night before zipping it up. Which creates a “greenhouse effect”, keeping them just warm and hydrated enough to ensure that my winter houseplant care efforts will be successful.
As mentioned, plants need far less water in winter. Even in warmer climates, less light still causes plant processes to slow down. Cutting back on the amount of water you normally use by ⅓ – ½ will provide them enough moisture to maintain their slower internal process through the winter.
Too much and they’ll start to show signs of stress. Overwatering may result in the following symptoms:
- Producing soft, weak, spindly shoots
- Yellowing leaves
- Browning leaves
- Leaf Drop
- Root rot due to unused water saturating the soil
- Pests collecting on the soil or foliage
Succulents are especially susceptible to these symptoms because they naturally store water in their foliage during times of drought and cold.
It’s also true that different plants absorb water at different rates and some may not need to be watered as frequently. Some also like to remain dry for a bit before receiving more water.
So, understanding the needs of the specific plants you have is beneficial in good winter houseplant care. There are two methods that I rely on to tell me if a plant needs to be watered.
- The ‘finger’ test – Stick your index finger into the soil about ¾” down. If it feels 80-90% dry, it’s time to offer more. If not, wait another few days.
- The ’soil pinch’ test – At the same ¾” depth, lift a bit of soil out and pinch it. If the soil sticks together, there’s still enough moisture in it. Wait a few more days before watering again. If the soil falls apart when pinched, it’s dry and your plant may need to be watered.
If you grow plants in self-watering pots, you’ll want to watch how quickly the reservoir empties in winter.
The wick will convey water to your plant’s roots at the same rate regardless of season. So, you may need to remove the inner pot and hand-water these plants, to avoid overwatering.
Above all, the water you use to hydrate your plants should be fresh, aerated water. Tap water often contains minerals and other elements that can cause leaf browning and root burn.
I keep a 4-liter jug under my kitchen sink, that I fill with tap water. Then, allow it to sit and aerate until my plants need to be watered.
When windows are sealed shut and the heater is running most of the time to keep us comfortable, the humidity level inside our homes may only be around 5-10%. Unfortunately, this isn’t conducive to quality winter houseplant care.
Most houseplants, even in a dormant state, still require 40-50% humidity in their immediate environment. Be on the lookout for signs of humidity stress in your plants.
Symptoms include browning leaf tips and the appearance of spider mites that are attracted to dry soil and foliage. The following options can keep a healthy layer of humidity around them.
- Spritzing them twice a day (once in the morning and again in the evening) will keep foliage hydrated and the evaporating mist will increase the humidity around them.
- Place pots in a pebble lined tray and fill the tray with water to just below the bottom of the pot. Keep this filled and the evaporating water from the tray will create a vapor barrier around your plants.
- Invest in an indoor greenhouse that you can house your plants in. Spritzing them before closing it will provide adequate environmental moisture.
- Invest in a seasonal, room humidifier, this will not only benefit your plants but keep your skin, hair and sinuses from drying out, as well.
Naturally, in temperate climates, these practices aren’t necessary. As indoor and outdoor humidity levels remain within a healthy range for houseplants throughout the year.
During their active growing season, houseplants often require fertilizing to increase needed nutrient flow.
But in severe winter climates, when their metabolism and growth slows, any applied fertilizer may result in forced growth that is weak and susceptible to pests and disease.
Root and foliar burn is also a common occurrence as your plants are not able to metabolize fertilizer the way they do in warmer months.
So, fertilizing isn’t a necessary concern in good winter houseplant care practices.
In mild climates, fertilizer can continue through winter. But, I suggest cutting it down by half in December and January. Because days are still shorter at this time, limited light results in slower metabolic processes.
Pruning (or pinching) is actually recommended in the final stages of your winter houseplant care schedule. Especially with vining plants and indoor trees.
Removing yellowed foliage, or weak shoots that emerged during cold weather will encourage thicker bushier growth. And the pieces cut can potentially be rooted in water or soil to make new plants!
Large, overgrown plants and indoor trees can also be cut back at this time. Bare stalks with a cap of leaves at the tips can be cut back to encourage the growth of multiple side shoots.
How much to cut these back depends on the type of plant. If you’re unsure, just cut a few back and watch for new growth before cutting back more.
The task of grooming houseplants can be very therapeutic. And to ensure the ongoing health of your plants, use only a pair of sharp, sterilized pruning shears.
Microscopic bacteria could be hiding on used shears just waiting to be transferred to a plant’s open cut. Spray them with a touch of disinfectant spray as you go from plant to plant.
When pruning, always cut to the natural growth of your plants. Leggy stems and branches should be removed just before a node and large stems should be removed just below the soil line, at the plant’s base.
Never partially cut leaf or tear a stalk as this could leave your plant vulnerable to pests and disease.
At the end of winter, around mid-March (or mid-September in the southern hemisphere) is when houseplants begin to detect longer days and warmer weather. These environmental changes trigger a slow awakening from winter dormancy.
And the potential need for a second, late winter houseplant care step. Moving houseplants, that require it, into bigger pots. When spring arrives, roots will start growing down and out and they’ll need more room to do that so the plants can start growing again.
New pots should be no bigger than 1” more in diameter than the previous pot. This extra space will provide necessary growth room but not so much that nutrients and water flow right past the root ball without benefitting it.
There are certain signs that your houseplants will give you when it needs repotting. One visible sign is if you see roots growing out of bottom drainage holes. This indicates that roots have no more room to grow inside the pot and it’s time for a bigger one.
But, sometimes a constricted root ball is not so obvious. If your plant doesn’t seem to be responding to water or nutrients, this may be the result of the root ball becoming so compacted that it’s not able to absorb and distribute these needed elements.
The least messy and most beneficial way that I’ve found to repot a plant is as follows:
- Choose a larger pot no more than 1” larger in diameter.
- Add a bit of soil to the larger pot to accommodate for the difference in height.
- Place your potted plant inside the larger one (Yes, plant and pot!)
- Fill the gap between the two pots with soil and gently press it in.
- Remove the smaller pot to reveal a perfectly sized hole for the plant’s root ball.
- Gently remove your plant from the smaller pot
- Place the root ball into the hole.
- Water well to encourage new root growth and minimize shock.
The continuous airflow from HVAC systems tends to push a lot of dust around. Dust often settles on misted houseplant leaves, resulting in a thin dusty paste. This can block the level of light absorption and food production needed to maintain health through dormancy.
In warmer months, this can cause stunted growth and yellowing. So, this pasty film needs to be wiped off from time to time. Making this #8 on my list of winter houseplant care steps.
Leaf shining products are available for purchase but a simple damp cloth is best. As many of these products aren’t suitable for all houseplants and don’t actually remove the dust. On larger, woody plants, the stems can be carefully wiped down, as well.
Simply support each leaf in one hand and gently wipe from where the leaf meets the stem out to the tip. Wipe stalks upward, from the base of each toward the top.
9. CHECK for PESTS
A warm, cozy home not only provides us with the perfect environment to get through the colder months, but bugs love it, too.
Many indoor pests can thrive and multiply at this time, sustaining themselves on juicy houseplants. The good news is, when all of the above points of good winter houseplant care are followed, pests don’t stand a chance.
It’s a good idea to check for them periodically, though. I do this when checking to see if my plants need water. But, how do you know what you’re looking for? Let’s take a look at the most common pest types:
Mites – tiny spider-like arachnids, less than 1 mm in length, that like overly-humid conditions. They may be too tiny to see. But, their presence is evident by the appearance of silver-colored dots in various patterns on the underside of leaves.
Mealy Bugs – small, white insects that like to lay their eggs in moist, warm soil. And look like a cotton-like material on leaves and stems. This appearance is often mistaken for fungus or mildew.
Aphids – tiny, pear shaped pests that are white, brown or light green. These typically appear on the sappy underside of leaves when plants are stressed by dry, infertile soil. A few can’t do much damage but an infestation could cause severe wilting due to excessive sap removal.
Whiteflies – soft, winged insects that feed on the sap of houseplants resulting in foliage damage and leaving the plant vulnerable to disease and fungal infections. Yellowing leaf drop and a black, sooty film on the plant are signs of an infestation.
Others are more successfully propagating by dividing their tubers or rhizomes, like ferns, palms, spider plants and peace lilies. Further research will determine what specific plants fall into each of the following categories:
Rooting Leaf Cuttings – With a sterile pair of shears, remove a healthy leaf with a clean cut. Never tear a leaf off or use your fingernails. A clean cut will heal but a tear may leave your plant vulnerable to disease and pests.
Allow the cut end of the leaf to dry out for a day or so. This will allow the cut end to heal and be able to root nicely.
Once dried, insert two-thirds of the leaf into fresh, fertile potting mix. Gently press the soil around the base of the leaf, water thoroughly and place it in a sunny spot. New growth should appear within 2 weeks to a month, depending on environmental conditions.
Rooting Stem Cuttings – Make a clean cut, with sterile shears, just below a node. The cutting should be 2” – 6” in length. The node is where new roots will grow from. To propagate in soil, remove any leaves along the bottom two-thirds of the stem and place those two-thirds into fresh, fertile potting mix.
Gently press in the soil around the stem and water thoroughly. To propagate your stems in water, simply stick the cut end of the stem in fresh, clean water and place it in a sunny place. New roots should appear in a couple of weeks.
Root Ball Division – Carefully remove your plant from its pot, to avoid root shock. With your fingers, remove any excess soil from the root ball. Then, with a clean knife or pruning shears cut the root ball into sections. Each section should have roots as well as stems and leaves.
Immediately plant each of these sections in their own pots with fresh, fertile potting mix. Pot size should be in proportion to the size of the smaller root ball. Then, water thoroughly to encourage new root and plant growth. Once the divided plant becomes established in its new pot, new growth should follow.
This may all seem time-consuming and a lot to remember. But realistically, many of the steps in great winter houseplant care take mere minutes to do (it takes me two seconds to check for dry soil in plants I pass on my way to doing something else), while others take a bit more time.
Once you put them all into practice, they’ll become second nature. And the reward for your efforts will be healthy, beautiful houseplants and a therapeutic activity that lifts the spirit during those shorter, colder days.
Interacting with the Earth is one of our most primal instincts. In this age of technology and industry, its critical that we nurture that instinct for our own health and well-being. The more you grow, the more YOU grow.