Keeping indoor plants and seeds thriving can be challenging when you fail to provide a reliable lighting source, especially during scarce sunlight.
Follow this guide if you are unsure how much lighting your indoor plant demands and where to shop them.
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What are the Light Requirements for Indoor Plants?
All plants require light for photosynthesis, converting sunlight, oxygen, and water into carbohydrates or energy.
Like humans with varying appetites, plants boast changing light requirements. Here are four different factors you should know about.
1. Light Intensity
In simple terms, light intensity describes brightness (the amount of light energy that falls on a surface per unit area).
If you are wondering, the intensity or brightness determines how much light reaches or is available to the plant.
In fact, it becomes a crucial factor because too bright or dim lighting may not have a desirable effect on the plants.
It is measured in PPF (photosynthetic photon flux), lux, foot candles, or lumens to give you a better idea.
|Lux (sq. meter)||PPF||Foot Candles (sq. feet)||Lumens|
For example, bright sunlight (over 10,000 lux) can burn sensitive plants, while a dimly lit room (20-30 lux) will be insufficient for sun-loving plants.
2. Light Distance
Yes, distance from the light source can affect a plant’s growth because the intensity decreases as light travels away from its inception.
If the light is too weak, the plant may not be able to photosynthesize enough, and too intense light will burn the plant.
Remember these few tips when placing artificial light close to your plant.
|Seedlings||4-6 inches (100-152 mm)|
|Succulents||6-12 (152-304 mm)|
|Vegetables||12-14 (304-355 mm)|
|Flowering plants||6-12 (152-304 mm)|
Moreover, you must monitor the plant’s condition equally to adjust the light distance to ensure optimal growth.
3. Light Duration
Also known as photoperiod, the light duration determines how long a plant is exposed to light to attain desirable results.
It may be essential for germination, flowering, and fruiting, which require various duration of light.
Some plants require more exposure to light, 8 hours or more, than others, for example, flowers and vegetables.
Most indoor plants that bear foliage are called short-day or day-neutral plants that do well in short-light duration.
Check out this table to learn more.
|Factor||Duration per day|
|Flowering plants||14-16 hours|
4. Light Spectrum
Often referred to as light color, the light spectrum is vital for any plant growth.
Different wavelengths (measured in nm) of light affect plant growth differently, and certain wavelengths are necessary for specific stages of development.
- Most plants grow well in full-spectrum lighting, a combination of blue and red (400-700nm) with smaller amounts of green, yellow, and Infrared.
- Blue light (400 nm) helps with the vegetative growth and development of leaves.
- Red light (700 nm) helps with flowering and fruiting
- Far-red light (>700 nm) especially helps with germination.
However, you need not be too picky about the light spectrum as much as the duration, distance, and intensity.
Indoor Plants Based on Light Requirement
Indoor plants require as much light as any outdoor plant, but the light intensity and duration will vary.
Remember, indoor plants are attuned to living in the existing light conditions, where their growth will depend on the light available.
Before getting a plant or starting seeds, determine your space’s quality and hours of natural light. Then choose plants with light requirements that match your indoor environment.
That said, each indoor plant has a light requirement sufficient to observe healthy, even growth and is classified into three types.
|Low Light||Medium Light||Bright Light|
|Enjoy shade with light bright enough to read a newspaper||Need well-lit areas but despisee bright or direct sunlight||Thrive under bright light, sometimes even direct sunlight|
|Chinese evergreen||Grape ivy||Cacti and succulents|
|Cast iron plant||Elephant ear (Alocasia)||Citrus such as calamondin orange, kumquat, Meyer lemon|
|Ponytail palm||Norfolk Island pine||Hibiscus|
|Parlor palm||Asparagus fern||Culinary herbs, basil, thyme|
|Dumb cane||Jade plant||Ti plant|
|Dracaena||Rubber plant||Orchid cactus|
|English ivy||Fiddleleaf fig||Gardenia|
|Sentry or kentia palm||Begonias||Jasmine|
Plants with Special Light Requirement
The light requirement will vary according to the season, where plants require more light in the summer and less in winter.
Notably, plants native to tropical regions require more consistent light throughout the year and may need additional artificial lighting during winter to remain healthy.
Similarly, growing cannabis requires more light than other indoor plants.
Provide anywhere from 18-24 hours of light with a blue light spectrum between 400 and 500 nm during the vegetative stage from high-intensity discharge (HID) lights.
Germinating seeds indoors would be an exception, requiring a uniform light intensity throughout the growing period.
The light should be between 200-400 umol m-2s-1 for 14-16 hours each day and kept 2-6 inches above the tray, which is best achieved by medium or bright light.
How to Choose the Artificial Light for House Plants?
Choosing the best artificial lighting for your indoor plants would depend on their requirement, time of the year, and indoor growing conditions.
As previously mentioned, the best artificial lighting would depend on whether you are growing a low, medium, or bright light-loving plant.
Here is a table describing what artificial lighting your indoor plant would require.
|Low Light||Medium Light||Bright Light|
|A low light is similar to minimal lighting obtained from the north window||It is similar to moderate lighting received from east or west-facing windows||It is similar to bright light received from south-facing window|
|50-150 umol m-2s-1|
|150-250 umol m-2s-1|
|250-450 umol m-2s-1
|Only "understrory plants" like Dracaena, English ivy, and cast iron plants are appropiate||Appropriate for tropical plants like Begonia, Frns, Rubber plant, etc||Appropriate for succulents, citrus, vegetables, flowers, and fruits|
|It is not appropriate for germination||Germination is possible but may take longer||It is appropriate for germination|
|Plants are likely to grow slowly||Plants will grow moderately||Plants will flourish|
Based on this fact, you can choose the type of artificial light bulbs for house plants.
|LED||-Light emitting diode is the most economical grow light choice|
-It produces very little heat
-It offers wide spectrum of light
|-Higher up-front cost for larger space
-Increasing intensity would require adding multiple bulbs
|Fluorescent||-Old school lighting option for budget-friendly growers|
-It produces minimal heat so is less likely to burn the plants
-Available in T5, T8, T12 and CFL options
|-Inappropriate for germination
-Do not last long
-Uses more energy
|Incandescent||-They can cover large space for indoor garden|
-Cheaper up-front cost
-Good for medium light plants
|-Only emits 10% light, the rest is emitted as heat
-Not appropriate for bright light plants
-Offer high far red light
|HID||-High intensity discharge is good for bright light loving plants.|
-Appropriate for germination
-Appropriate for indoor garden, greenhouse, and farming
|-Energy inefficient and expensive
-Not appropraite for few small or ornamental plants
-Heats up too quickly
|Halides||-High-pressue sodium and metal halide|
-Appropriate for wider areas
-Commercial light supplements for greenhouse and farms
|-Only applicable for large scale farming
-Heats up too quickly
-Requires more distance between the light and plants
Best Grow Light for Plants Indoors
Here are a few best grow light recommendations, including some stylish grow lights for indoor plants.
|GE Grow Light for Plants||-Advanced red spectrum with high output PPF 15
-Highly energy efficent
-Appropriate for leafy, veggies, and fruits
-Hung at least 5-6 inchs above
|AeroGarden Harvest Elite||-High performance, full-spectrum LED light
-20 watt LED
-Appropriate for herb and ornamental plants that grow up to 12 inches.
-Includes guormet herb seed kit (6 pods)
|GHodec Grow Light for Indoor Plants||-6000K spectrum with 126 LED clips
-Equiped with 5 Red + 37 Sunlight White LEDs
-Timer setting available (4h,8h,12h)
-360 degrees adjustable goose-neck
-Height adjustability available
|BESTVA 4000W Led Grow Ligh||-4000 watts LED grow light appropriate for indoor garden
-Full spectrum lighting with 2x higher PPF
-Equipped with high-speed mute fans and aluminum radiators
-Applicable for germination, veg, and blooming by choosing custom setting
|iPower 1000 Watt HPS||-1000W digital dimmable electronic ballast (0%, 75%, 100%)
-1 x 1000W super HPS bulb 2100K; 1 x 1000W MH bulb 6000K
-6-inch air cooled hood reflector
-Appropriate for germnation, veggies, and fruits.
Keeping your indoor plans flourishing can be challenging without optimal lighting, especially when the sun is scarce.
Therefore, make the best of lighting by using sunlight and compensate with artificial lighting wherever possible.
However, be wary about the light requirement, intensity, duration, distance, and light spectrum for house plants before buying a grow light.