Grow robust seedlings, encourage houseplants to flower, and spur herbs to produce tasty shoots year-round with the help of indoor plant lights.

By Megan Hughes
Updated April 07, 2020
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While many houseplants do just fine indoors with whatever natural light comes in your windows, certain ones can be coaxed to bloom more reliably or will grow more healthy leaves with additional light from artificial sources. And if you're starting vegetable and annual flower seeds inside, they often need the help of lights to develop properly. While the amazing power of sunlight is tough to replicate indoors, thoughtful use of grow light fixtures fitted with simple fluorescent or LED bulbs can come close. Here's what you need to know about setting up the best grow light systems for your houseplants and seedlings.

several houseplants under a grow light in a kitchen
A mix of houseplants thrive under a grow light.
| Credit: Marty Baldwin

Grow Transplants with LED Lights

Smart lighting is key to getting a jump start on spring transplants indoors. Most interior rooms do not provide bright enough light to produce dense, healthy seedlings. Even a south-facing window often falls short when it comes to growing seedlings. In a bright sunny window, seedlings will usually germinate well and produce their first set of leaves and then the “stretch” begins as stems elongate and reach for more light.

Prevent the “stretch” by growing transplants with artificial light created by standard shop lights outfitted with fluorescent tubes or energy-efficient LED bulbs. These bright lights provide a combination of blue and red light waves necessary for good plant growth. Look for plants need.

Using Grow Lights for Houseplants and Produce

Illuminating your favorite blooming houseplant, such as African violet, will encourage the plant to come into bloom more quickly than if exposed to natural indoor light. Likewise, artificial lighting is key to a continued harvest of basil, rosemary, parsley, and other greens that are easy to grow indoors for a tableside treat during long winter months.

Flowering and fruit production for houseplants and edibles is spurred by red light waves. Choose a light source that provides plenty of red-wave-rich light. Warm-white light is deemed 2,700K to 3,200K on the Kelvin color temperature scale and is rich in red wave light. Look for the Kelvin rating of a bulb on the product packaging.

How to Use Grow Lights

Plan to illuminate interior plants for 12 to 14 hours a day. Leave the lights on for 16 to 18 hours a day and the plant will likely come into flower sooner. Transplants grow best when supplied with light around the clock. Leaving the lights on 24 hours a day compensates for the lower light level of the artificial light as compared to sunlight. Beware of utility bills with the increased use of power. The long illumination time is where LED bulbs pay off. Although more expensive to purchase up front, LED bulbs are exceptionally energy-efficient and longer-lasting than traditional fluorescent bulbs. Control light timing with ease and efficiency with the help of a timer.

Keep Grow Lights Close to Plants

Artificial lighting must be very close to plants to be effective. As the rays of light move away from the source, they dim significantly. Keeping lamps close to plants increases the amount of light received which keeps transplants compact, preventing long, weak stems. Position lights 6 inches or so above transplants, moving them up as the plants grow to maintain the 6-inch source-to-plant distance. Interior plants and edibles grow well when they are within 12 inches or so of the light source.

Use Simple Grow Lights Indoors

While there are many types of specially designed lights and fixtures for growing plants indoors, start with a simple and inexpensive system of fluorescent or LED bulbs if you are growing transplants. Blooming indoor plants and food crops will benefit from specially designed LED grow lights.


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