Plants have been evolving on land
for 500 million years,
give or take a year or two.
That's a lot longer than you and me,
and they've evolved to live in very particular light conditions.
Once we bring them indoors,
we become both their doctor and nurse.
So to avoid any major health issues,
we should know what suits them best.
Come with me and I'll throw some light
on the more or less shady world of indoor plants.
Leaves are the perfect expression of life.
They turn nutrients from the ground and light from the sun
into food for the plant.
Chloroplasts cover the surface of leaves, capturing the light,
and the chemical process that metabolises energy
is photosynthesis.
If leaves don't get enough light for photosynthesis,
they struggle and become leggy,
or in scientific terms, etiolated.
This is where the plant stretches upwards
in an effort to find more light,
often reducing leaf growth
and losing colour to conserve energy.
So let's begin in the glare of full sunlight.
These plants have generally evolved
with narrow but thick leaves.
This decreases transpiration and reduces heatstroke and burning.
Full sun means being exposed
for between six to eight hours without shade.
They are tough plants with stems to match.
Examples of these plants include cacti,
succulents
and crotons.
These plants need a lot of light,
and levels outside are much stronger than indoors.
So unless you have a sunroom
or a big north-facing picture window,
they'll struggle and start to look a little droopy,
dried out, and even change colour, like crotons.
But if you've got the right spot,
and they're leaning flat against the window,
loving the sunlight,
rotate them every few weeks to even up their growth.
Nature is ever-adaptive,
so one size doesn't fit all when it comes to tropical plants.
Some, like ficus and monstera,
generally prefer bright light,
even though some species can adapt to full sun.
Get some advice from your local nursery if unsure.
And if you're struggling to find more light indoors,
grow lights are a great idea.
Or mirrors.
Moving down a notch from full sunlight
we have filtered light or partial shade.
Outdoors, these plants tolerate around two to four hours
of direct sun,
so when indoors,
I put them in a shady spot behind sheer curtains.
They've evolved under the canopy of a forest,
so think of them as needing dappled light.
Examples include ferns,
aroids
and philodendron.
If they get too much sun,
they'll scorch and need moving.
Scorched leaves will eventually drop,
or you can simply snip them off with your secateurs.
Low-light plants are the chilled members of the family.
They take their time and have evolved to be slow growers,
requiring less sunlight.
These shady characters included the snake plant,
alocasia,
peace lily,
aphelandra,
begonias
and the ZZ plant.
Low light doesn't mean no light.
Indoors, keep these plants a few feet away from the window,
or in a shady aspect of a room.
To ensure they maximise their ability to photosynthesise in low light,
wipe down the leaves with a damp cloth,
removing layers of dust that could form a barrier.
When you bring plants indoors
and wonder why they aren't doing too well,
take into account their millions of years of evolution in nature
and give them the light they need.