Homegrown: Lighting tips for houseplants

The following is by Iowa State University Extension, Linn County Master Gardener, Jane Schildroth:

(Note from Cindy: Congratulations to Jane and 12 other interns who recently received their Master Gardener badges!) 

This time of year always finds me scrambling to figure out where to put all the plants that have moved into the house from outdoors and from a 3-season room.  I like my plants but I don't like the “jungle” feel I get when there are too many green things in one space.  I also hate watching them struggle through the winter.  I'm pretty certain now that lighting is the biggest challenge.  Some of us have great places that plants just love – and others of us don't.  Either way, there are some pointers that can help.

 If the lighting isn't right for a plant, it may develop a “leggy” look or abnormally-sizes leaves.  It may also have dead older foliage and lighter-than-normal leaf color.  It will also exhibit more disease and pest problems.  Sometimes an experiment is in order.  Move the plant to a location with different lighting and keep doing everything else the same.  The plant will let you know if the light is more satisfactory in the new location.

 Generally, plants perform best near a sunny window because the sun provides all the necessary wavelengths.  Household lights are usually deficient in the red and blue wavelengths needed for photosynthesis.  Fluorescent lights provide the blue but can lack the red wavelengths while incandescent lights emit mainly yellow, which aren't useful to the plants.

 Observe how the light comes into your home all during the day before concluding if the light is high, medium or low.  An overhang or porch may reduce the hours of sunlight that your plants receive.  Usually we think of southern exposures as high, east and west as medium and north as low.  Artificial lights can achieve low or medium light, but just realize that the lights need to be 4-6 inches from the top of the plants to be effective.

 To find a list of plants that thrive in low, medium or high light, go to http://www.extension.iastate.edu/Publications/RG402.pdf.  Hopefully if you apply this information to your “indoor garden,” the results will be more satisfactory than just guessing.  Healthy growth and beautiful blooms may be yours to enjoy this winter!