Houseplants growing outdoors are accustomed to receiving more sunlight than they do indoors. Research has revealed that tropical plants grown under bright conditions produce "sun leaves" while those grown under darker conditions have "shade leaves."
These leaf types differ structurally in that sun leaves have less chlorophyll (the substance that plants use to convert sunlight to energy), and the chlorophyll that is present is deeper inside the leaf. Sun leaves also tend to be thick, small and numerous, while shade leaves are thinner, larger and fewer in number.
Plants need time to adjust when they are moved from one light condition to another. If they are forced to change too quickly, they will drop their sun leaves and produce new shade leaves -- a lengthy, stressful process. If the conversion conditions are less extreme, the plant can transform sun leaves into shade leaves -- a natural, less stressful process.
So how do we help our houseplants acclimatize to the lower light levels found indoors? Houseplants brought in from outside should be placed in an area of the home that receives plenty of light then gradually moved to their permanent, darker location. This shift can take four to eight weeks to complete.
During this time, do not be alarmed if a few leaves turn yellow and drop off. This is natural as the plant is trying to balance itself in the new growing environment.
Likewise, gradually allow the soil to dry out by watering less, and do not fertilize. The goal for the next six months is to survive -- not thrive.
-- Bruce Chladny is horticulture agent at K-State Research and Extension-Douglas County. For more information, call him at 843-7058 from 8 a.m. to 5 p.m. weekdays.