The easiest time of year to kill a houseplant is definitely during the winter. Houseplants are put to the test by harsh growing conditions like low light levels, dry air, shorter days, and frigid temperatures.
Making care routine adjustments to accommodate seasonal growing circumstances is the key to ensuring that plants survive the winter. Review the fundamentals to provide your indoor plants with the best care during winter.
Winter causes the sun to set later in the day, which results in a 50% reduction in light levels near windows. During the winter, indoor plants that thrive near a sunny eastern or northern window during the summer may require a southern or western exposure. Similarly, plants near windows in the west or south that require filtered light in the summer might be able to endure direct sunlight in the winter.
To aid plants in adjusting to shifting light conditions:
- If it’s possible, move plants nearer to the windows.
- Window cleaning will maximize light transmission.
- For the winter, move plants to new areas next to windows with more light.
- Cleanse plants to allow leaves to utilize the light that is available to the fullest.
- Add synthetic lighting. Fluorescent lights are sufficient. They generate less heat and are less expensive than conventional grow lights. For best results, place bulbs 4–12 inches away from plants.
Tropical plants, which make up the majority of indoor plants, like daytime temperatures of 65 to 75 F and nighttime temperatures of around 10 F lower. Low temperatures (below 50F) can be problematic for many plants.
In order to make the thermostats more comfortable for you, keep in mind that your plants also require some thought.
- Keep plants away from heat sources and cold gusts.
- Maintain a few inches of space between plants and external windows.
- Plants should be moved away from windows at nightfall in cold climates if windows freeze over at night. Additionally, you may tuck a thick shade or another insulating item between the plants and the glass.
In the cold, homes might only provide 5–10% relative humidity. Houseplants prefer 40–50%. Brown leaf tips and the presence of pests like Spider Mites are indicators that plants are being stressed by low humidity. Learn how to increase the humidity around plants in simple methods.
Overwatering is the most frequent issue that indoor plants encounter throughout the winter. 95% of indoor plants require the soil to almost totally dry out before watering. How do you determine whether plants need water?
- Don’t only test a small area of the soil’s surface. When the root zone is dry, plants require moisture. Insert your finger up to two inches into the ground. Water the soil if it’s dry.
- Pick up the pot. When soil gets dry, it becomes lighter. Lift pots right away after watering to feel the texture of the moist soil.
- Plants won’t need water as frequently if winterized rooms are humidified. Water must be added to dry air.
- The only exceptions to this rule are citrus and ferns in pots, both of which require continually moist soil. If you are uncertain, always do your research.
Never let plants sit in water that gathers in the drainage saucer overnight when you water.
Fertilize plants all winter long in mild climates. Winter fertilization of indoor plants is not recommended in the coldest climates with little natural light. When springtime outside plants begin to grow, fertilizer can be resumed.
In the spring and summer, when most indoor plants are actively growing, is the ideal time to repot them. Potted woody plants that entirely hibernate in the winter are the exception. Transplant those in the early spring before the buds break.
- Numerous advantages of houseplants include bettering indoor air quality and lowering sickness rates.
What degree of indoor temperature is appropriate for houseplants?
Depending on the type of plant, you should decide when to bring it inside. However, it’s important to keep in mind that many common flowering container plants (such as begonias and hibiscus) are truly tropical natives and dislike chilly nights. A chill can significantly slow down an organism’s growth, even if it doesn’t kill them.
When nighttime temperatures begin to fall below 55 to 60 degrees Fahrenheit, it is preferable to bring indoor plants (12-15 C.). Look for pests that may be hiding in the soil of container plants before bringing them indoors. For 15 minutes, immerse each pot in warm water to force any insects or slugs to the surface. If you notice a lot of activity, spray your plant with an insecticide and repot it.
This is also an excellent time to repot any of your plants that are outgrowing their containers.
The plants that require the most light should be placed in windows that face south or under grow lights when you bring them inside. Plants that require less light can be placed in windows that face east or west. The light will probably be dimmer than it was outdoors no matter where they go. This shock may cause some leaves to turn yellow and fall. But after it adjusts to the new light level, your plant ought to produce fresh, wholesome leaves.
Water your plants less frequently than you did when they were outdoors so that less of it evaporates. On the other hand, the air inside your home is probably less humid. This issue should be resolved by setting your pot on a dish on a layer of gravel that is maintained consistently moist. Simply watch out that the water level in the gravel doesn’t rise above the level of the container or you run the risk of root rot.
What degree of cold is required before bringing your plants inside?
When nighttime temperatures fall to 45 or 50 degrees Fahrenheit, experts advise bringing your plants inside.
Are indoor plants too cold for 45 degrees?
The majority of plants planted indoors are indigenous to tropical or subtropical regions, where temperatures are significantly and consistently higher than those found in the majority of our gardens.
As a result, certain rooms in our homes have the ideal temperature for their growth.
Most plants: You’ll discover that most indoor plants flourish between 60 and 75 degrees Fahrenheit (15 – 24). Some plants (not many) require less, while some (a few) require a little bit more, but plants that thrive in this range are suitable for use in homes and businesses (because many rooms are kept close to these temperatures, already).
Spray misting the leaves of your plant can assist increase humidity when temperatures are over the acceptable threshold for that plant, which is approximately 75F (24C). Some plants, which are frequently placed in humidity trays and misted, thrive well in warmer temperatures.
Temperature too high: While most plants are alright outside, interior temperatures above 75F (24C) are too hot for most plants. They don’t have the same conditions, such as air humidity and sunlight that encourages growth without limiting the heat, therefore they can’t tolerate greater temperatures indoors.
Too low: This is a far bigger issue than higher temperatures because it severely impairs plant growth and kills plants, especially when excessive water is also offered.
Rough guide for the lowest temperatures
- 60°F for tender plants (15C)
- 50 to 55F for half hardy (many indoor plants) (10 – 13C)
- 45F Hardy (7C)
Examining the individual recommendations for each plant is the fastest and most precise way to determine the ideal temperatures.
Is 40 degrees Fahrenheit too chilly for houseplants?
A house plant could potentially be in danger at any temperature below 50 degrees. Your plant won’t be able to grow if the temperature drops too low. It will eventually perish from the cold. The majority of indoor plants, though there are few exceptions, like conditions that are between 65 and 75 degrees during the day. They typically prefer temperatures between 55 and 65 degrees at night.
Low temperatures can be tolerated by the majority of tropical houseplants, but they won’t grow. In general, indoor plants can’t tolerate temperatures below 50 degrees.
Can Houseplants Survive 40 Degree Temperatures?
40 degrees is too cold for the majority of indoor plants. This is particularly true when the temperature lowers to 40 degrees from a warm one. One of the most frequent reasons for plant death is sudden temperature drops.
Your plant won’t be able to endure cold temperatures indoors, even if it can do so outdoors. A plant is unlikely to be able to tolerate the cold if it becomes accustomed to the conditions inside.
You should cover your plants if your house will be at 40 degrees for an extended amount of time. However, if you believe the chilly weather would just stay one night, you don’t need to cover.
If you choose to cover your plants, be sure to choose the right covering. Only cover plants that are in direct sunlight with black plastic. Clear plastic shouldn’t be used to protect plants from the sun since it gets too hot.
How cold is 38 degrees for plants?
Eek!! The forecast calls for evening lows at or below freezing with frost! What shall I do?
The good news is that there are a few simple things you can do to help protect your plants against cold conditions. Remember that a frost is different from a freeze. Additionally, following a frost in the fall, some crops, such as beets, parsnips, and carrots, only get sweeter to taste.
Know Your Frost Dates
Priorities first! Always keep in mind the first and latest frost dates that often occur in your area.
The first day of the year that a frost occurs is regarded as the first frost date as the fall weather begins to cool. The first freeze date of the year will come as the weather cools further, typically a week or two later (this is what kills most annual plants). The first freeze day and first frost date in Missoula are both in the middle of October.
The average last frost date is the first day of the year we may anticipate a frost when the weather starts to warm up in the spring. The last frost date in Missoula is May 18.
These dates are typically correct but by no means exact because they are based on historical meteorological data that was gathered over a 30 year span. Be diligent, keep an eye on the forecast, or set up a weather app alert to be notified when the nightly lows change. Use the four techniques listed below to temporarily safeguard your plants when temperatures are predicted to drop to near or below freezing.
Assess: How Bad Is It?
Plants are harmed by temperatures at or below freezing for longer periods of time than just a single day. Similar to how lower temperatures are tougher on plants than those at or near freezing, really cold temperatures that linger for several hours are significantly harder on plants than those that are at or near freezing for only an hour or less. When assessing the seriousness of the weather report, bear this in mind along with a few of the crucial definitions listed below.
When the temperature is forecast to drop to between 36 and 32 degrees Fahrenheit, a frost advisory is issued.
When there is at least an 80% likelihood that the temperature will drop to 32 degrees Fahrenheit or lower, a freeze warning is issued.
The majority of plants are severely harmed by a severe or harsh freeze, 25 degrees Fahrenheit or lower.
What must I do in advance of bringing plants inside?
- your plants in water. Put your plants, planter and all, in a bucket with a solution of insecticidal soap and water (1 tsp of soap per liter of water, or follow the instructions on the container) for around 15-20 minutes. This method of de-bugging plants also has the added benefit of providing plants with a thorough watering. To keep your plants clean when you pull them out, skim debris off the surface of the water while they are submerged beneath you. Take them out, rinse them out, and thoroughly clean the planter once they have finished soaking. Before bringing them inside, spread out some towels and let them absorb any extra moisture. Before watering them once more, make sure the soil is fully dry.
Since your plants will receive far more light outside than they will indoors, it’s crucial to gradually acclimate your houseplants to lower light levels in order to prevent transplant shock.
- Your plants need to adjust. Start by relocating your plants to more and more shady settings each day over the course of a few days, and then bring them indoors. The more time you give them, the better; somewhere between 5 days and 2 weeks is advised. After being relocated, they could drop a few leaves at first, but they’ll quickly get used to their new surroundings!
- Trim a little bit. You may foster new growth that will be more adapted to life inside by pruning your plants when you move them inside. This will also assist limit their size.
- The period is ideal for re-potting. If you discover that one of your houseplants is rootbound while de-bugging it, this is an excellent moment to upgrade it to a new container. Or, you might need to pot a plant for the first time if you’re trying to bring one in that was previously planted outside. In that scenario, remove the garden soil from the roots and entirely replace it with potting soil. Find out more by reading our repotting guide!
- Hold them apart. You may want to keep your plants separate from any other houseplants you may have for a few weeks after bringing them inside so you have time to monitor and ensure your de-bugging efforts were successful. It’s simpler to treat just your recently relocated plants rather than all of them if you missed any pests.
Once your plants are secure inside, keep in mind that the manner you take care of them will alter depending on the season. Consider plants in the winter as being on the verge of hibernation since their growth will be drastically slowed down due to reduced light and less thirst. Additionally, you typically won’t need to fertilize! Before watering, make sure the soil is at least two down and dry to the touch. For more details, read our watering essentials guide and our watering in the Wally Eco guide.
Your plant babies are now indoors for the winter, where you may enjoy their leaves and preserve them for the next year.
When are potted plants too cold to survive?
Planting too early might result in a crisis if a cold snap is impending, whether it was because you were seduced by some striking hue at the garden center or simply wanted to start the gardening season early. It’s not difficult to help your seedlings survive the great frost, but it does take some planning.
When temperatures drop, you can usually rely on improvised protection for plants. The necessary tools must be prepared in advance to protect plants from frigid mornings for larger plantings, such as a food garden.
Knowing when prized vegetation starts to turn frost-burned brown will help you know what to do when freeze warnings are in effect. As a general rule, plants typically freeze when the temperature stays at 28°F for five hours.
There are, of course, exceptions to this rule. When temps drop to 32–33F, seedlings often die because of their delicate new leaves. There are many low-temperature thresholds for tropical plants. Some collapse at temperatures below 40°F, while others break down at 35°F. Other plants are naturally resistant and can endure temperatures as low as 18 to 20 degrees Fahrenheit. Do a search in gardening books and internet resources to discover the threshold for your plants.
Take it up
Moving plants away from potential danger is the simplest cold-protection strategy. Potted plants and seedlings in flats both benefit from this. Moving plants onto a porch with a roof, into a garage or shed, or under a deck frequently provides sufficient shelter.
Rely on Water
Just before sunset, water the soil to raise the temperature of the surrounding air overnight as the water evaporates. Water-filled buckets or gallon jugs should be left in the sun all day. Move them close to threatened plants at night. Air temperatures will be moderated by the water, and if it freezes, heat will be released. To boost midday heating, paint a few water-holding containers black for best results.
the air flowing
The biggest harm is done to plants by cold, motionless air. To prevent frost from accumulating on plants, you can use an electric fan all night to create a breeze. Never forget to keep electrical connections dry.
Plants Should Be CoveredPlants should be covered with sheets, towels, blankets, cardboard, or a tarp to protect them from everything but the harshest freezing (28F for five hours). Inverting baskets, coolers, or any other container with a firm bottom over plants is also an option. Before it gets dark, cover plants to keep warm air in. Coverings shouldn’t ideally contact the foliage. If windy conditions are anticipated, anchor cloth coverings.
When the temperature rises and the frost has melted in the morning, remove coverings. Under dense covers, heat from the sun can accumulate and cause plant death.
Blankets that collapse
Row covers, or gardening blankets, should always be accessible. These covers are created in various thicknesses from plastic or synthetic fibers. Lay row covers directly on the plants, or suspend them over a bed with pegs to form a tunnel.
Activate lights
An incandescent light bulb produces enough heat to raise the temperature of the air around it just enough to keep a plant from freezing. For this method to operate, bulbs must be close to plants (within a distance of 2-3 feet). (Fluorescent bulbs can’t produce enough heat to complete this task.)
Defend specific plants
Set up hot caps
At planting time, stiff plastic containers with venting holes are placed over the individual seedlings. Hot caps function similarly to cloches (small greenhouses), but the daily task of applying and removing the covering is eliminated by venting holes. Use plastic two-liter bottles or gallon jugs with the bottoms cut off and the lids removed to simulate a hot cap (but saved). In the evenings when the weather turns chilly, replace the lids.
A Wall O’Water tepee, which encircles individual plants with a sleeve of water-filled tubes, is a variation on the hot cap concept. During the day, the water absorbs the heat of the sun. The water gently freezes at night, releasing the sun’s stored radiant heat and preventing the air within the tepee from becoming frosty.