Growing plants indoors under supplemental lighting

Kent Kobayashi
Tropical Plant & Soil Sciences Dept.
College of Tropical Agriculture & Human Resources
University of Hawaii at Manoa

Benefits. Plants are such a joy to have indoors! They are attractive, fascinating, and keep us in touch with "nature." Not only do plants provide us with a psychological lift, they are beneficial:

Plants can enhance the decor of any office!

Plants "Clean" Air Inside Our Homes. Laura Pottorff, Colorado State University.

Although this web site deals with supplemental lighting in the office, it is also applicable to your home, apartment, or dormitory.

Location. Ideally, plants should be placed in an indoor location where they receive some sunlight daily--whether direct or indirect. However, this may not always be possible. For example, plants in an office with a north facing window may receive no direct light coming through the window.

A variety of plants growing near a north facing
office window.

Leave well enough alone. Supplemental lighting is not always or automatically needed. Some plants do fine on their own. Ordinary room light is sufficient.

Away from any office window, this
plant is still growing well.

Plants in a waiting area outside elevators.

Matching the plant to the location. If you are looking for a plant to place in a particular location, try to select appropriate plants for that specific lighting situation. For example, Chinese evergreen can tolerate low light intensity and would be suitable for semi-shady places.

Guide to selecting houseplants. Anne M. Streich, University of Nebraska.


Getting started. Try to place indoor plants near a window to get some direct, indirect, or diffused light. If the lighting is inadequate and your plants need supplemental lighting, there are two basic kinds of lighting--fluorescent and incandescent. Other kinds of indoor lighting, such as high pressure sodium lamps or metal halide lamps, are not be covered in this web site.




Light intensity tends to be low so you are limited as to the plants can be grown. Again, try to select plants that can tolerate lower light conditions.

Indoor plants--cleaning, fertilizing, containers and light requirements. Debbie Shaughnessy, Clemson University.

Types. Common types of fluorescent lights are cool-white and warm-white.

You can use

It is commonly recommended to use a cool-white tube in combination with a warm-white tube. While cool-whites and warm-whites are relatively inexpensive, wide spectrum tubes and high intensity fluorescent tubes are a bit more pricey.

Set up. Fluorescent tubes typically come in 2-foot and 4-foot lengths. The 2-foot length works well if space is limited.

Plants growing under a 2-foot fluorescent light
fixture attached to a wooden shelf.

A simple set up can be a twin-tube fluorescent shop light fixture from a local hardware store or garden shop. A fixture that holds two 48-inch 40-watt fluorescent light tubes covers an area approximately 4 feet by 8 inches.

These fixtures come with chains to suspend the fixture over the plants so you can adjust the height according to your plants and raise the fixture as the plants grow taller. Besides being hung from shelving, a fixture can be attached to a shelf (for example, with screws).

Chrysanthemums growing under 4-foot fluorescent fixtures
and incandescent lights suspended from metal shelving.

An alternative is getting a light cart although this will be more expensive. It does offer the advantages of mobility (wheels) and attractiveness. Supplies for caring for the plants can also be stored on the shelves.

A light cart with a fluorescent light
fixture suspended above the plants.




Types. Regular; plant grow lights.


Lighting can be provided not only from the top, but also from the sides.


Whatever the light source, you can use reflective plastic sheet (film) to direct more light to your plants. Mylar can be added to room walls to reflect available light. An alternative is white plastic sheet.

Plastic films that diffuse light can also be used.

Plants growing under fluorescent lights covered
with a plastic film that diffuses light.


Light emitting diodes (LEDs) are becoming more prevalent as a light source, for example, in flashlights. However, they are still relatively expensive for office and home use.

LED light sources for plant research, Kevin M. Folta, University of Florida


Supplemental lighting for indoor plants. DIY Network.

Guide to a green thumb. Heidi Bornhorst, Honolulu Advertiser.

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