Philodendron prefers a warm, humid environment and will not tolerate extreme temperatures. Therefore, your plant can suffer irreparable damage if subjected to freezing winds or blistering heat.
Philodendron’s temperature tolerance varies significantly among species, but it cannot withstand temperatures below 55°F (13°C). Temperatures of 75-85°F (24-29°C) and 65-70°F (18-21°C) are ideal for this plant. The wrong temperatures are evident by sunscald, leaf curling, shoot dieback, drooping, wilting, and leaf drop.
What Temperature Is Too Cold For Philodendrons?
For their entire lives, philodendrons have thrived in tropical rainforests such as those in the West Indies, Brazil, and Mexico, where it is always hot and humid.
Leaving your plant in these conditions for an extended period can cause cold damage or injury. Frost or freezing temperatures are fatal to philodendrons.
Keep your Philodendron away from air ducts, open windows, cooling vents, and any other cold drafts in the room it’s in.
For an extended period, your plant leaves will turn black and die if it is exposed to temperatures below 55°F (13°C).
Stunted growth from cold injury can also cause dark or brown spots on leaves.
In addition, your Philodendron is likely suffering from low humidity, shorter days, lower light levels, and possibly overwatering in the winter.
Remember that cold drafts can cause significant leaf drops, resulting in a naked and leafless philodendron. In addition, cold damage may have caused parts of the foliage to turn black.
What Temperature Should Philodendrons Be In?
Each philodendron species prefers temperatures that fall within a specific range, and there are over 200 varieties.
However, temperatures around 65°F (18°C) are ideal for most philodendrons. You should never let your home’s nighttime temperature drop below 55°F (13°C).
Generally, you should keep your philodendron environment at 75-85°F (24-29°C). At night, you should keep the temperature between 65 and 70°F (18 and 21°C).
These temperatures, coupled with high humidity, good airflow, and plenty of moisture, are ideal for them.
When temperatures drop to as low as 60°F (15°C), philodendrons lose a lot of their vigor and growth potential.
If the temperature falls below this level for an extended period, they may go into dormancy.
All growth activity on your plant stops during this phase of dormancy.
There is a near-total cessation of all biochemical processes, including transpiration, photosynthesis, and respiration.
Philodendron employs this strategy to conserve energy until the onset of spring.
Your Philodendron will face a slew of problems when it goes into dormancy. You’re more than likely to overwater it, for starters, leading to root rot and other issues.
Signs Your Philodendron Has Been Exposed to the Wrong Temperature
Keep an eye out for these signs that you’ve been exposed to the wrong temperature.
 Dry or Brown Leaf Margins
Dry, brown leaf tips and edges on your Philodendron may indicate that it has been subjected to temperatures beyond usual.
This is frequently accompanied by low humidity and direct sunlight exposure.
Heat stress and excessive moisture loss cause the tips of the leaves to dry out and turn crunchy or crispy.
Philodendrons that are overly dehydrated due to sitting in the sun or dry air will exhibit the same symptoms.
Leaf tips that have been exposed to hot drafts may also become brown or dry. Make sure your plant is not sitting near a radiator, fireplace, or vents that circulate hot air.
These natives of the tropics enjoy a high level of humidity. The soil loses water due to increased evaporation when the temperature rises.
To fix this, you must relocate your Philodendron away from direct sunlight, hot drafts, or scorching windowsills.
If it’s outside, move it to a shadier location. The best way to avoid burning your plant indoors is to either move it away from the window or use a curtain to block the sunlight.
Your Philodendron might also benefit from a rise in humidity in its environment. Misting your plant may be a good option during the summer’s hottest days.
Humidifiers are an option (Amazon link). Another option is to set the pot on a shallow tray of wet stones or pebbles.
 Shedding of Philodendron Leaves
Temperature stress causes Philodendrons to shed their leaves. If your Philodendron is losing foliage, the temperature is either too cold, hot, or drafty.
You’ll see the same effect the first time you bring your philodendron home from the greenhouse, outdoor garden, or nursery.
After you’ve moved or repotted your plant, follow these guidelines for the first few days afterward.
The good news is that this is rarely fatal to philodendrons. To get new leaves, all you have to do is adjust the temperature and other growing conditions.
A well-balanced liquid fertilizer can help rejuvenate your Philodendron during the growing spring and summer months.
You’ll have to put your plant in a warm, draft-free area of your house if it’s losing leaves because of the cold temperatures of winter.
 Drooping Leaves
Cold drafts or low temperatures will cause the growing medium to become less dry than usual, which will harm your Philodendron’s ability to thrive.
Likewise, overwatering your plant will cause drooping leaves if you continue to water it usually.
Cold damage to Philodendron leaves causes them to droop and curl. Frost or freezing temperatures have damaged the cells, so this is happening.
Eventually, the leaves will wilt due to the loss of turgor pressure and overall rigidity in the damaged cells.
 Browned or Blackened Leaf Surfaces
Excessive heat exposure can cause leaves to turn black or brown and crispy on the surface, so be on the lookout.
Too much direct sunlight usually results in blackened leaves. For example, if you leave your Philodendron outside in the hot summer sun, the leaf tissue will be damaged due to overheating.
If you leave your plant in these conditions for an extended period, the black patches will continue to grow.
In my experience, this usually happens to plants that I’ve neglected for an extended period near or on the windowsill of a west- or south-facing window.
Plants directly in the path of air vents, radiators, fireplaces, or central heating are more likely to develop blackened leaves. Slowed growth and leaf drop are expected as a result.
Remove any leaves that are entirely blackened. Use cooling fans or move your Philodendron out of the way of direct sunlight to help keep it healthy.
 Curling of Leaves
Curled leaves often accompany dry, brown leaf edges. In most cases, curled philodendron leaves can be attributed to sunlight, water dehydration, and over-exposure to high temperatures.
Most philodendron species aren’t accustomed to the extreme heat of harsh sunlight.
Therefore, it will show signs of temperature shock and sunlight damage.
It’s best to stay out of the sun during the summer, but a little winter sunlight isn’t a bad thing.
Sunburn or scorch on the philodendron leaves is the most apparent sign of overheating. Sunscald is characterized by the browning of the leaf margins and yellowing of the tips and edges.
As a general rule, new, delicate shoots and foliage are more susceptible to sun-scorch than older leaves.
All leaves exposed to direct sunlight will eventually fade and become bleached.
You should move your Philodendron indoors or to a shady area of your home if it gets sunburned. The sunscald leaves will not recover, so it is best to remove them.
 Leaf Yellowing and Die Back
Heat and overexposure to direct sunlight are most likely to blame for yellowing philodendron leaves.
Unfortunately, this frequently occurs without the proper or gradual acclimatization.
Overwatering, insect infestations, and nutrient deficiencies can also cause yellowing and dieback in philodendron leaves and extremely hot or cold temperatures.
Can Philodendrons Be Left Outside?
As long as temperatures don’t fall below 60°F (15°C), you can leave your philodendrons outside in the open.
I often bring my plants outdoors during the summer because we live in a more temperate area.
But, first, I have to see if the nighttime temperatures remain above 60°F.
If it’s consistently cold, you’ll want to bring your philodendrons in.
These tropical plants are perfect for patios and backyards in USDA Hardiness Zones 10B through 11, where they will thrive. (Source: University of Florida)
How Do You Take Care of a Philodendron During Winter?
Winter frost and cold temperatures can do severe damage to philodendron plants.
They’ll likely go dormant until early spring if temperatures fall below 55°F (10°C). You probably want to see your green beauty thrive as an avid gardener.
It is necessary to overwinter philodendrons inside if you live outside of USDA Hardiness Zones 10b to 11.
They’ll be fine and even thrive in the right place in your home throughout the winter.
The good news is that philodendrons adapt quickly to living indoors.
However, to ensure that your plants are adequately cared for in the winter, there are a few things you need to keep in mind:
- Reduce watering frequency: Your plant will need less and less water as the weather gets cooler and the days get shorter. When the top two inches of soil are dry, you should only use water.
- Prune off unhealthy parts: Remove any long leggy stems and yellowing foliage from your Philodendron before bringing it indoors.
- Inspect carefully for trouble: Inspect your plant thoroughly before bringing it inside to ensure there are no pests or decaying parts of the plant.
- Keep it away from drafts: If possible, keep it away from open windows and doors, air ducts, radiators, window panes, and cold floors, which can all cause drafts.
- Stop fertilizing: You should only fertilize your plant once a year. Feeding it any fertilizer in the dead of winter is a bad idea.
- Invest in foliage grow lights: Keeping your philodendrons in bright light is best to avoid dormancy. LED grow lights are a viable option in this situation.
- Maintain proper humidity and air circulation: Ensure that your plant has adequate ventilation. Add moisture to the air with the help of a humidifier or pebble trays.