Kenneth Freeman
22 February 2021

 


Many houseplant novices are concerned that their plants are not going to get enough light.  Everyone remembers from school biology lessons that light is the energy source that drives photosynthesis - the reaction that converts water and carbon dioxide into carbohydrates that fuel the growth and development of the plant. But how much light do indoor plants really need, and how important is natural light?

Why is light important to plants?

Light is important for plant survival for three main reasons: as the energy source for photosynthesis, as a regulator for daily and seasonal triggers (e.g. flowering and leaf drop) and to trigger daily physiological activities (e.g. the opening of leaf pores or the orientation of leaves and flowers).  Some of these functions rely on the quantity of light, some on the quality of the light (its colour) and some on the timing and duration of light.

A lot of what a houseplant needs is determined by its biological origins: jungle or desert, for example, and the amount of seasonal variation experienced in their natural conditions.

It might surprise you that of the 256,000 or so flowering plant species (and a few thousand ferns) currently living, there are only a few hundred that can survive happily indoors.  Those that are most adaptable to indoor conditions are the plants that come from the parts of the world with the least seasonal variation - near constant temperatures and day-length.  These areas are the tropics and sub-tropics.  Houses and other indoor environments are similarly constant.  That is also why in the UK, almost no garden or wild plants will survive for long indoors - we have significant seasonal variation here.

Do my houseplants need sunlight?

The short answer is “no”.  Certainly, some houseplants benefit from being placed near windows, but many will not thrive in such bright conditions.  No houseplant will tolerate being put in direct sunlight outdoors - even on warm days. Sunlight is so intense compared with indoor conditions that leaves will be permanently damaged.  Even on a cloudy winter’s day, the light outside can be as much as 20 times as bright as on a windowsill of a well-lighted room, although your eyes won’t notice the difference.  Indoor plants are specially grown on nurseries where they are adapted to be able to cope with the low light found in the home.  

There are myths about the need for natural sunlight for plants and that somehow artificial light sources aren’t good enough.  For the most part, as far as the plant is concerned, a photon is just a photon.  Whether it came directly from the sun or from an LED light bulb, it makes no difference - quantity is what matters, not the source.

Which plants do well in really low light conditions?

In most homes, there are places that get very little light at all. Possibly because the room is little used and the lights stay off for a long time, or there is an alcove or shelf just crying out for some greenery.  Fortunately, there are plenty of robust plants that not only survive in low light, but actually thrive there.

The jungle floor

Most low light plants have their natural origins living in the dark shady places of tropical rainforests.  Here the conditions are constantly warm, moist and rarely illuminated by direct sunlight.  The plants that come from these environments have many common features: large, tissue-thin leaves, usually very dark in colour (they have a lot of chlorophyll to capture as much light as possible) and sometimes heavily patterned plant leaves - these are all clues as to whether your plant can manage in the dark.

Let’s take a look at some of the plants that we offer that will work well in the shadier spaces of your home.

Aglaonema "Silver Queen"

Aglaonemas are native to the Philippines, parts of tropical Asia and Africa.  There are many species and varieties used as ornamental plants and they all share the same compact habit with highly variegated leaves. 

Aglaonemas grow wild in Southeast Asia and the Philippines, although the hybrid that led to "Silver Queen" occurred in a nursery in Florida.  The wild relatives of Aglaonema "Silver Queen" grow on the forest floors of the jungles of Southeast Asia, and they thrive in warm conditions with good (but not direct) light and moist soil. They will tolerate quite low light conditions if you cut back on watering a bit too.

Alocasia species

Alocasias are a group of aroids from the tropics of Asia and Eastern Australia, often noted for their dramatic foliage, sometimes richly patterned.  Like Aglaonmena, Alocasias are plants of the tropical rainforests and are adapted to low light levels, and moist, warm conditions.  In the home, they are well suited to bathroom plants and shaded spots in other rooms.  They really do not like direct sunlight and their leaves can become discolored if exposed to bright light for too long.

Asplenium ferns

These ferns are commonly known as Bird’s Nest Ferns, and we offer two species: Asplenium antiquum and Asplenium nidusBoth species have long, simple, glossy green fronds and a characteristic “bird’s nest” centre - an area of tufty brown hairy growth at the heart of the foliage from where new fronds arise.  Aspleniums are epiphytes (and sometimes lithophytes), this means that they live on the branches of trees or in rock crevices (and can be displayed attached to a piece of lava rock).  Their natural habitat is in the forests of the wet tropics, where water is plentiful and where the foliage of big trees shade them from direct sunlight.

Begonias

Begonias are a vast group of plants of nearly 2,000 species that hybridize freely, making them very difficult to classify.  Species that originate on different continents, and that are relatively distantly related are even able to hybridize, and this feature has led to the development of very many interesting decorative plant varieties, often with incredible colours and patterns on their leaves.

The wild relatives of the Begonias that foli8 offers come from the tropical rainforests of South America, Asia and Africa, which have warm and humid climates.  Most species are forest floor plants that grow in shady or semi-shady conditions, so will offer a dramatic splash of colour in the darker areas of your home.

Calathea and Ctenanthe species

Calatheas their close relatives, Ctenanthe, are native to the rainforests of South America, and they are among the most sensitive of plants to direct sunlight or over-bright conditions.  Their leaves are incredibly thin and very often highly patterned - a feature that is thought to be a camouflage to make it difficult for browsing animals to see them in the dappled shade of the forest floor.  We offer three types of Calathea and Ctenanthe, and they look great in a group as well as displayed on their own.

Ficus elastica

Ficus elastica is the original rubber plant.  Elastica obviously means elastic, and refers to the sticky latex that exudes from the plant whenever its stems or leaves are damaged.  This was used for the manufacture of soft rubber goods, such as elastic bands and erasers.

All cultivars of Ficus elastica have large glossy leaves which are often very darkly coloured.  Some varieties are variegated and some have bright red leaf sheaths.

They all originate from the jungles of India and Malaysia and cope really well in low light conditions.  Their durability in darkly-lit houses has been known for over 200 years: Ficus elastica was first introduced to the UK as a decorative plant in 1815 - a period not associated with well-lit indoor spaces.

Microsorum ferns

These are ferns from the old World tropics.  Microsorum diversifolium is a jungle floor creeping plant, whereas Microsorum punctatum grows much like Asplenium ferns, as an epiphyte or lithophyte.  Both species, however, are ferns of shady environments and do very well in shady, or semi-shady spaces in the home.

Monstera adansonii

Monsteras grow in the wet, windy, humid tropics.  They are epiphytes, which means that they climb up and on the branches of tall trees to get to brighter conditions away from the forest floor.  This means that they like warm temperatures indoors, and, as the plants we provide are young, they can cope with quite gloomy, shaded conditions.

Philodendron “Imperial Green”

 

Philodendron "Imperial Green" is a large-leaved plant notable for its glossy, leathery foliage and robust constitution.  The leaves grow from a central rosette on thick fleshy stems, sometimes tinged deep red.  It is a compact variety and does not climb.

"Imperial Green" is a typical jungle floor type of Philodendron that originated in the warm, humid rainforests of South America, and is very well suited to low light levels.

Spathiphyllum wallisii

The Spathiphyllum wallisii, or Peace Lily, is a vigorous plant with large, long, glossy dark green leaves - clues that this plant is well suited to dark places.  The dark leaves which contrast sharply with the pure white, arum-like flowers that are borne on slender stems.  Each flower may grow up to fifteen centimetres long, contains a creamy-white, maize-like spadix and turns green with age.

All Spathiphyllums do well in poor light and can tolerate occasional over watering, so are ideal for novice houseplant keepers. Direct light can cause the leaves to become bleached and damaged.

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