Top 5 Tropicals For A Cool Room

Do you have rooms in your home that are markedly cooler in winter than the rest of the house?  Believe it or not there are some cold tolerant tropical plants that will do just fine in these cooler rooms.  By cold tolerant I do not mean that you can put them out in a cold porch for the winter – they do have their limits!

As the days cooled down in fall you probably noticed that your houseplants perked up and looked happier.  Our hot summer weather and lack of humidity pulled water from their root systems (transpiration) and the plants lost more water through their leaves and stems than they should.  Because of this your plants looked a bit sad and you were watering more often.

One of the first rules of keeping houseplants in a cool room is that you can markedly reduce the amount of water they receive during the winter. 

Due to shorter day length in winter, tropicals do not go into dormancy but greatly slow their growth.  This is especially true in a cool room environment as the room air temperature is cool and the plant’s soil becomes cool too.  In a cool room their transpiration rate slows down and the plants require less water to maintain their slow or non-existent growth.  Overwatering causes many problems; one being root rot.   

The day and nighttime temperatures required by tropical and flowering tropical plants really vary by species.  The ideal daytime temperature range for most tropical plants is 21-23 degrees C.  Nighttime: 18 to 21 degrees C.  The Top 5 Cool Room Tropicals named in this blog can tolerate cooler temperatures than the above both day and night.

Ferns, spider plants, pothos, palms, philodendron and peace lily like nighttime temperatures from 15 to 18 degrees C.  They cannot tolerate nighttime temps under plus 10 degrees C.  

Some flowering plants hold their flowers longer in cooler nighttime temperatures in the 15-16 degrees C. range. Others, such as African Violets, Airplants and Begonias need warm temperatures to flower. Other plants such as the Christmas Cacti need a period of cold temperatures to initiate flower buds.

The following are the Top 5 Houseplants That Tolerate Cool Rooms in Winter

All of these plants will tolerate room temperatures of 15 degrees C and above if kept in a bright room location. 

Norfolk Pine    (Araucaria heterophylla) Conifer species

Norfolk Pine is a popular Christmas gift plant that you can also enjoy as a houseplant year round.  Decorated with tiny lights and ornaments, they make a great hostess gift or to include in a mixed holiday planter.   Norfolk Pines are native to Norfolk Island, which is found halfway between New Zealand and New Caledonia in the Pacific Ocean.  In their native habitat, Norfolk Pines will grow to 61 m. with a trunk diameter of 3 m.  In our homes they will reach from 2.5 to 3 m. tall. 

Norfolk Pines like bright indirect light.  Medium to low light will cause them to become less full and leggy. Do not overwater, but keep them at a lightly moist level at all times.  If your Norfolk Pine dries out too much the lower branches will brown and fall off.  Fertilize in spring and summer when the plant is actively growing.  Propagation is by 15-20 cm. tip cuttings from the terminal ends of branches in summer.  Dip cut ends in a tiny amount of rooting hormone and insert into a moist sterilized medium. 

Norfolk Pine can be toxic to pets; causing mouth and digestive issues such as irritation and vomiting.  Some humans can experience skin irritation.

Cast Iron Plant   (Aspidistra elatior)

The Cast Iron Plant is aptly named.  This plant can tolerate a range of light and various adverse conditions.  While it can tolerate low light conditions, it is best grown in bright, indirect light.  Keep lightly moist in cool conditions. Fertilize in spring and summer with an all- purpose, water soluble houseplant fertilizer.   Propagation is by division of the root ball in spring and summer. 

Cast Iron plants are not toxic to humans, dogs and cats.  

Snake Plant    (Sansevieria trifasciata)

In the past few years there have been many new Snake Plant cultivars come into garden centers.  Some are short and wide, while others are cylindrical and pointy.  Some cultivars such as the favorite ‘Laurentii” will reach heights of four feet!  While they will tolerate low light locations, they do the best in bright indirect light.  In a cool room you will rarely have to water – usually once a month to once every six weeks during the winter.  Propagation is by root division or leaf cuttings (2-3 inch segments).   Transplant and fertilize in spring and summer. The Snake Plant is toxic to humans, dogs and cats.   Snake Plant flowers smell wonderful! 

ZZ Plant     ( Zamioculcas zamiifolia)

I am sure you are not surprised to find this plant on this list!  ZZ is usually referred to as a low light plant but it does better in bright indirect light.  Again, this is a plant that can go a long time between waterings, but if left to dry out completely will drop leaflets.  The ZZ Plant will reach a height of three feet.  The flower is similar to a Peace Lily flower but not as impressive.  Propagation is by division of the tuberous rhizomes.  You can also place one leaflet cut off at the base into a moist potting medium and cover with plastic.  This may take a few months.  A heat mat under the cutting pots may speed up the rooting process.   ZZ plants are toxic to humans, dogs and cats. 

Succulents  

Many succulents are native to Africa and can tolerate the deserts of North America.  Their thick fleshy leaves, stems and roots store water which makes it possible for them to do well in arid conditions.  Agave and Aloe Vera are succulent plants.  In a cool room they do the best in bright, indirect light.  You may not need to water them at all through the winter months as too much water will cause root rot.  When transplanting, use a very fast draining soil mix.  Fertilize in spring and summer with a water soluble cacti fertilizer.  Propagation is by stem cuttings or leaf cuttings inserted into a slightly moist cacti soil medium.  Before inserting into the rooting medium, let the cutting ends dry and callous over.  Dip the ends into a small amount of rooting hormone and stick into the rooting medium.  A heat mat will warm the soil and may move the rooting process along a little faster.  Most succulents are not toxic to humans, dogs and cats.  There are a few that are toxic though, so please check the name of the succulent you are purchasing and do a bit of homework.

Plants that tolerate cool room temperatures ( minimum 15.5 degrees C):

- Bird of Paradise              

- Clivia                                    

- Jade Plant

- Christmas Cacti

- Philodendron

- Fiddleleaf Fig

- Ponytail Palm

FYI

As mentioned previously, all tropical plants have their limits when enduring a cool or cold indoor environment.

Signs that the temperature is too low in your home: You will see your plants experience stem browning or blackening. This is indicative of stem and root rot.   Leaves will lose their rigidity. curl down and inwards toward the mid vein.  They may also yellow or white and if frozen will turn black.

Avoid frosty windowsills and do not locate tropicals – especially Christmas flowering plants -near cold drafty doors.