Thursday, 03 September 2020 11:44
By Peter Bowden | Home & Garden

Soon it will be time to move any houseplants that spent the summer outside back inside for the winter.  Before we do, we’ll want to take precautions to make sure they don’t bring home pests picked up during their summer vacation.  If we bring a plant indoors with only a couple of aphids on it for instance, it can become a big problem in a small amount of time.  Once inside with heat and no natural predators to keep them under control, these insect pests reproduce quickly and can infest your other houseplants.  The last warm days in September gives us the chance to take preventative measures. 

The first step is to thoroughly spray your inbound plants with an insecticide.  My favorite is insecticidal soap.  It kills just about any insect commonly found on houseplants on contact.  It also kills mites which often go undetected since they are so small.  Spraying outside while the weather is still warm gives us a chance to be thorough without making a mess inside.  Spray every inch of the plants until the insecticidal soap is dripping off the leaves.  Pay special attention to the undersides of the leaves since this is where mites like to hide.  Spray again a week to ten days after the first spraying.   

In addition to the spraying, put some systemic insecticide into the soil of inbound houseplants especially hibiscus that seems to attract pests.  Systemic insecticides are drawn up into the plant through the roots and are pumped out through the stems and leaves until it permeates the entire plant. 

Any sucking insects like aphids or scale suck up the insecticide and die.  Systemic insecticide lasts for several weeks so it kills any insects that hatch from eggs after the plant was brought inside.  It takes a couple of weeks to get absorbed by the plant so it is a good idea to use it a week or more before the plant comes inside.  Naturally, you shouldn’t use systemic granules on any edible plants you plan to rescue from outdoors like herbs.

After spending the longest days of the year outside, our houseplants have become spoiled.  Long, warm sunny days with breezes required them to drink plenty of water.  Once they move inside, their demand for water will drop off considerably as the days get shorter.  Don’t water on a timetable.  Check the soil before you water.  If you even think it feels moist, don’t water, and check it again a couple of days later.  NEVER let the plants stand in water for more than a few minutes.  There is no quicker way to drown a plant than to leave it standing in water. This is what kills most houseplants…overwatering. 

Even though our houseplants live all year, they slow way down once inside.  Once they come inside, stop feeding them until March or so when they start to show signs of new growth.  Then feed them, but mix your food at 1/4 strength until it’s time for them to go outside in spring.

We love houseplants for the greenery they provide during the grey days of winter, so let’s help them make the transition as gently as possible.


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