Improve your houseplant success and grow more plants by using indoor supplemental lights. Recent advances in lighting have provided us with increased options for indoor growing and decreased the overall cost and energy usage of grow lights. In addition to the long, bulky lights often used for seed starting, more choices are now available to suit different needs and styles.
When grown in insufficient light conditions, plants show symptoms in various ways. Some indications may be:
- Smaller leaves than normal
- Variegated or brightly colored foliage turning solid green
- Slower plant growth than usual
- Leggy or sparse growth
- Browning leaf tips and edges
- Plants leaning towards the light
Room corners that are far from windows seem like a great spot for houseplants, but rarely have enough natural light for success—this is an example of the perfect spot for a grow light!
Although it can seem a little intimidating to read about different light features, it is really not super complicated. It’s important to understand a few terms that will help you figure out which light is best for you and your plants. To make it simple, we have done the research for you and selected two of the best lights we found to carry in our stores:
- MiracleLED Wide Angle Grow Lite: a simple bulb that can be installed into your existing light fixture or desk lamp
- Soltech Aspect LED Growlight: a stylish, pendant-style growlight that provides the ideal light spectrum for lush growth while also fitting in with your home décor
Incandescent, Flourescent & LED Lights
Incandescent lights tend to have high heat output, a short lifespan, and are not energy efficient, but often have a low purchase cost. They must be about 24 inches above plants to avoid burning.
Flourescent lights have a low heat output, last longer, and are more energy efficient than incandescents. They often come in CFL form or long, thin tubes and can be 6–12 inches above plants.
LED lights have a very low heat output, are long-lasting, and are extremely energy efficient, but purchase cost is usually highest.
Color of Light
“Full-spectrum” is a term used with many grow lights—this is meant to indicate the color and “temperature” of the light. Filters are used to copy color variations of the white light from the sun, giving off a “warm” light color. “Daylight” bulbs are easily confused with full-spectrum, but are not the same thing. They have a “cool” color or appear as more of a blue-white light.
Colored lights are also available for more specialty growing. A violet-blue light spectrum favors chlorophyll production and vegetative growth while red light stimulates and supports flowering and fruit formation.
Color Rendering Index (CRI)
The CRI helps measure how light appears to our eyes; a way to measure how accurately light renders the colors of objects it bounces off of compared to natural light (e.g. “Does this light make red look red?”). Full-spectrum light has a CRI of 90% or higher while daylight bulbs are only at about 80%.
Temperature of Light (Kelvin Scale)
Another way to express the quality of light as cool or warm is by measuring in Kelvins. The higher the number, the cooler/bluer the light appears (6000 Kelvin has a blue-white light; 3000 Kelvin has a yellowish glow).
Watts, Lumens, Lux (Lumens/Square Meter) & PAR
A watt is a unit of power, measuring the amount of energy used. A lumen is the direct measurement of light output or brightness that is visible to the human eye (a 60-watt light will output about 700 lumens). PAR (photosynthetic active radiation) is the light radiation that plants use to photosynthesize. Lumens are for humans, PAR is for plants. PAR levels decrease the further you get from the light source (counted in photons and micromoles).
Light Placement & Running Times
The distance at which the light should be from your plants depends on brightness and coverage. If using as the only light source, it’s best used for medium to low light plants. The closer the light is to the plants, the brighter it will be, but overall lighting surface area is decreased. The Soltech Aspect light, for example, can be placed 3 feet above plants and provide light in a 3 by 3-foot area. As supplemental lighting, place up to 4 feet away for bright, indirect light (great for a Fiddleleaf Fig) or up to 2 or 3 feet away for bright light plants such as succulents and cacti. For most general growing purposes, lights are best run on timers for 12–16 hours each day with the dark period coinciding with natural nighttime.
MiracleLED Wide Angle Grow Lite (bulb)
- 9w energy use comparable to 150w power; cool burning
- Low operating cost; estimated lifespan of 20,000 hours
- 270 degree, wide angle coverage
- 5000K light temperature
- 1000 lumens, 1900 micromoles
Soltech Solutions Aspect LED Growlight (pendant-style, plugs directly into wall socket)
- 20w (small), 40w (large) energy use; cool burning
- Low operating cost; estimated lifespan of 90,000 hours
- 3000K light temperature (warm light)
- 1500 lumens (small), 3000 lumens (large); CRI value 97%
- 5 year warranty; designed, assembled, and built in USA
- Includes light fixture and bulb, 15-foot cord, timer, and hardware for hanging