Many people with houseplants move some of them outside for the summer to give them better growing conditions and help them recover from the stress of an indoor environment. But as fall approaches and night temperatures approach 50 F, it is time to think about bringing plants inside for the winter. Plants that have spent the summer outside should be inspected for insects and disease before bringing them inside. A sharp spray from a garden hose can remove insects or mites from houseplant foliage. Insects in the potting soil can be forced out by soaking the pot in a tub of lukewarm water for about 15 minutes.
Houseplants that have been kept outdoors are accustomed to receiving much more sunlight than they do indoors. So how do we help houseplants acclimatize to the lower light levels inside? Houseplants brought in from outside should be started out in an area of the home that receives plenty of light, and then gradually moved to their permanent, darker location. This process should take four to eight weeks depending on the degree of difference in light levels between the initial and final location of the plant.
Understanding plant processes allows us to anticipate potential problems. Acclimatization gives houseplants a greater chance of retaining leaves and avoiding the stress of completely replacing them.
Kansas State Research and Extention