Lighting Basic Facts
A healthy plant needs sufficient light for growth.
Make sure the plants in your office or home have light requirements that match the environment.
Additional lighting can provide necessary illumination when there is insufficient daylight.
Various styles and sizes of artificial lights are available in many different types to match your needs and budget.
Lighting plays an essential role in the growth of houseplants. Light is essential for photosynthesis, the process by which plants convert light, oxygen and water into carbohydrates (energy).
Grass, flowers and seeds require energy to keep growing, blooming, and producing. Plants cannot manufacture carbohydrates without sufficient light, they lose their reserves of energy and die.
How Plants Adapt with Lighting
When plants like this geranium don’t get enough light, they grow leggy.
Without enough light, plants fail to produce chlorophyll, which is the green pigment in plants, making them pale green, yellow, or white.
Plant stems can become “leggy,” meaning they become long and thin and appear to be reaching toward the light source.
Insufficient light leads to the development of long space on the stem between the leaf nodes (the point where the leaf emerges from the stem).
Plants that do not receive enough light may also drop their leaves, especially older leaves.
It is possible that a variegated plant (leaves with multiple shades of green and white) will become fully green.
It is possible for flowering plants not to produce flower buds at all.
When plants are overexposed to light, they may have scorched and bleached leaves.
Choosing the right plant for your available light
Part of the day can be blocked by overhanging roofs.
Find out what type of light your space gets prior to buying a plant. Then choose plants whose light requirements are compatible with your indoor setting.
It may be okay to grow a plant in lower light conditions. However, the foliage will keep its denseness and flowering will be promoted with more light.
Low light
(PPF: 50-150 umol m-2s-1 / 50-250 foot-candles / 10-15 watts)
An indoor plant that needs low light would be suitable for a north-facing window or a fairly dark corner.
Plants of the low-light family require little sunlight. In their native growing environments, they grow as “understory plants” which means they grow beneath larger trees.
With less light, plants grow slower and use less water. Do not over water by touching the soil.
Medium light
(PPF: 150-250 umol m-2s-1 / 250-1,000 foot-candles / 15-20 watts)
Medium-light plants are well-suited to east-facing or west-facing windows as long as they are not placed too close to the windows.
They’ll dry out more slowly than low light plants, so don’t over water. Feel the soil beforehand to avoid overwatering.
Plants benefit from the maximum amount of natural light coming in from a south-facing window.
High light
(PPF: 250-450 umol m-2s-1 / more than 1,000 foot-candles, more than 20 watts)
For locations with bright light, such as south- or southwest-facing windows, a high-light plant would be suitable.
High-light areas can be hot, making plants dry out more rapidly. Check these plants more often and water when the soil is dry.
Houseplants for different indoor light conditions
You must choose plants that can thrive in the light conditions you have in your home, just like you would when decorating a garden in sunny or shady areas outdoors. Furthermore, you may decide to increase light energy to your plants by adding artificial grow lights.
Under the following lighting conditions that provide optimal growth conditions for indoor houseplants, the following plants have been identified.
Low Light Plants
Plants that grow as an understory in low light conditions, like the Dracaena trifasciata, can be found in Africa, Madagascar and Asia.
Low light is commonly defined as light “bright enough to read a newspaper.” The foliage of low-light plants tends to be more abundant than flowers.
Low-light plants would be ideal for a north window or a rather dark corner. These plants grow beneath the larger leaves and branches of other plants in their native environments.
- Chinese evergreen (Aglaonema)
- Cast iron plant (Aspidistra)
- Ponytail palm (Beaucarnea recurvata)
- Parlor palm (Chamaedorea)
- Dumb cane (Dieffenbachia)
- Dracaena
- English ivy (Hedera helix)
- Sentry or kentia palm (Howeia)
- Homalomena
- Pothos (Epipremnum)
- Philodendron
- Lady palm (Rhapis excelsa)
- Snake plant (Dracaena trifasciata; formerly Sansevieria trifasciata)
- Peace lily (Spathiphyllum)
- Arrowhead plant (Syngonium)
- Zee zee plant (Zamioculcas)
Medium Light Plants
Some species of low- and medium-light plants, such as pink Begonia and two Chinese evergreens (Aglaonema), provide adequate light in places that are fluorescent-lit, such as the office lobby.
In areas of good light such as near an east-ward facing window or near a westward facing window, these plants grow best. Many office buildings have fluorescent lighting throughout the day, resulting in a shortage of light for medium-light plants.
- Elephant ear (Alocasia)
- Norfolk Island pine (Araucaria)
- Asparagus fern (Asparagus) Ferns
- Rubber plant (Ficus elastica)
- Fiddleleaf fig and weeping fig (Ficus)
- Begonias (Begonia)
- Spider plant (Chlorophytum)
- Grape ivy (Cissus)
- Aucuba leaf (Aucuba Japonica)
- Croton (Codiaeum)
- Jade plant (Crassula)
- Flame violet (Episcia)
- Schefflera (Schefflera)
- Wax plant and Hindu rope plant (Hoya)
- Peperomia (Peperomia)
High Light Plants
It is necessary for citrus plants to receive bright light in order to flower and set fruit. As a rule of thumb, most plants grown for their flowers need to be grown in bright lighting such as windows that face south or southwest.
- Citrus
- Ti plant (Cordyline)
- Orchid cactus (Epiphyllum),
- Gardenia (Gardenia)
- Jasmine (Jasminum)
- Kalanchoe (Kalanchoe) Geraniums Poinsettia
- Non-hardy azalea (Rhododendron)
- Orchids
- Caladium
Artificial Lighting
It’s possible to add artificial lighting to your space when there isn’t enough natural sunlight in the area. Once you know how much natural sunlight is available, you can decide to add supplemental lighting.
LED and fluorescent bulbs are the most common types, but you may also find incandescent bulbs when shopping around. You can find them at your local hardware store or online. Each type has pros and cons.
LED
- Very energy efficient
- Long-lasting
- Wide spectrum of light
- Do not produce too much heat
- Wide variety of styles and sizes
- Higher up-front cost than other bulbs
- Bright lights can be distracting
Fluorescent
- Moderately energy efficient
- Cheaper up-front cost
- Some only produce light in the blue-green spectrum, but others have a wider spectrum that includes red light; check the label
- Do not last as long as LEDs
- Use more energy than LEDs
Incandescent
- Cheapest up-front cost
- Energy inefficient
- Create heat
- Do not last as long (in some cases)
- High far red light causes plants to stretch