Grow Lights for Indoor Plants – Getting Started

Delicious tomatoes in the dead of winter? Award-winning violets? Fresh garden herbs all year round? Grow lights for indoor plants make it possible to cultivate indoor plants such as these any time of year in any climate.

Growing at home with grow lights.
Care for plants in the comfort of your own home with grow lights.


By following a few simple tips, everyone can exercise their green thumb indoors. So how do you use grow lights to produce the best plants not under the sun? Here are some tips and ideas to get you started.

Setting Up an Indoor Plant Growing Area

Consider your indoor garden plot. Whether it’s a shelf, basement area or an entire room, look at how much space you have and pot plants and beddings accordingly. Depending on the type of plant, group the pots or trays 4 to 8 inches apart to allow for growth and easy access for pruning and care.

Sprouts growing under light.
Sprouts thrive under a nurturing lighted environment.

You’ll also want to make sure you purchase lights that will illuminate your entire plantings area. You may need more than one bulb or light source to fully cover your growing area.

Plants under a violet-blue grow light.
TIP: Violet-blue light promotes plant growth and red light promotes plant budding. LED grow lights may look strange but they contain both types.

Choosing a Type of Grow Light

Grow lights should provide the proper spectrums of light for photosynthesis which is the key to plant growth. Violet-blue light offers a light in the 400 – 520 nanometer range that encourages chlorophyll absorption, photosynthesis and growth. Red light in the 610 – 720 spectrum range promote flowering and budding.

There are a number of types of grow light types available, each with their own strengths and characteristics.

Incandescent grow bulbs are the least expensive technology, but are also the least efficient and have a high heat output. Average lifespan is 700 hours.

An example of incandescent grow light bulb.
An incandescent grow light bulb. Although they are the least expensive option, their high heat output and low efficiency make them the weakest contender for grow light options.

Fluorescent grow lights have a low heat signature and produce a decent spectrum of light for growing. Tube lights or compact fluorescents in a reflector are both available. Lifespan averages 10,000 hours.

A CFL bulb from OTT-LITE.
An example of a CFL grow light bulb. CFL bulbs promote longer-lasting life hours and a better light spectrum for growing.

LED grow lights offer the latest technology on the market today. Extremely energy efficient, they have an ultra-low heat output and offer an ideal light spectrum range. Offering low energy usage, low heat and color optimized for growth, we think LED lights are the most efficient, effective and customer-friendly way to grow plants at home. Average LED lifespan is 50,000 hours.

An grow light using LED arrays.
An LED grow light array. This technology uses the least amount of heat output and offers more energy savings, making it a great choice for indoor plantings.

High-Intensity Discharge or HID bulbs produce light through an electric arc between tungsten electrodes inside a tube fused with alumina. These specialty bulbs have a very high light output level and are commonly used by commercial growers.

Metal Halide lights use mercury vapor mixed with metal salts to create a powerful light source. They use a special fixture and, like HIDs, are commonly used by commercial outfits.

Basil grown under a grow light.
TIP: Place grow lights directly over plantings to mimic natural sunlight.

Grow Light Placement Tips

Hanging or placing lights over the plant beds or pots is the best arrangement, as it mimics natural sunlight from overhead and exposes all sides and leaves of a plant to the artificial light.

As a rough guide, incandescent grow light bulbs should be at least 24 inches over your plants. Fluorescents and LEDs have a lower heat signature, so they can be placed 12 and 6 inches over plants respectively.

Keep adjusting the placement of the grow light as your plants develop and mature to maintain the proper distance. Consult your particular model and type of design for exact specifics and directions.

And remember that the lighting level required for growth indoors depends upon the characteristics of the particular plant being grown. Depending on what you want to grow, you may need different lights set a different heights for specific plant areas.

An LED grow light placed directly over plants.
TIP: LEDs have a low heat signature and can be placed very close to plantings.

How Long Should the Grow Light Be Left On?

Darkness is actually very important for the plant growth cycle. During the day, sunlight helps plants produce energy through photosynthesis. At night, however, plants break this energy down for growth and flowering in a process called “respiration”.

Different types of plants need different amounts of light. As a general rule of thumb, most vegetables and flowering plants need 12 to 16 hours of light per day, with flowering plants at the top end of that range. Plan on giving most plants at least 8 hours of darkness per day.

Check your seed packaging or plant tags, or ask at the nursery for specific suggestions. And make sure you turn your grow lights off every once in a while. No one likes to work 24 hours a day – even plants!

An example of a light timer from GE that can be used to time grow lights.
TIP: Use light timers to automatically turn your grow lights on and off each day.

Grow Light Questions

Got questions? We are here to help! Visit one of our Lamps Plus store locations to get help purchasing grow lights or grow light bulbs, or contact us to speak with one of our American Lighting Association trained Lighting Consultants.

Photography Credits: Photo 2 – Potted tomato plants (Wikipedia), Photo 7 – thanks to Claire Barnes, Photo 8 – Herbs beneath grow lights (Wikipedia)

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