Expert: Darlene K. Kittle - 2/26/2005

Question
my mom gave me the stock(tree) of one one her house plants and i noticed alot of little flies coming out of the dirt when i got it home...now all my house plants have these flies..
i am looking for a home remedy if possible and hope you can help

Thank you
Lori

Answer
Lori,

The bugs are fungus gnats. They are there because the soil is mostly peat moss and it has been overwatered and the roots may be beginning to rot. Set the plants in the sink and remove the drain tray to drain as much water as possible. Then do not water till the soil feels very dry.   You can also pick up a bag of horticultural charcoal and a bag of perlite at you garden center. Then gently unpot the plants and remove as much potting soil as possible without disturbing the roots too much. Then mix the soil with the same amount of perlite and add a handful of charcoal. Then repot the plants with the newly mixed soil. Your soil will drain better and not attract fungus gnats in the future. As a temporary kill method you can water the plant with rubbing alcohol.  It will not hurt the plants roots but will kill the fungus gnats. Just be very careful not to overwater in the future because fungus gnats are in the same family as fruit flies. If you leave a bannana on the kitchen counter and it gets mushy they come out of nowhere and go for the banana even in the middle of winter. If you overwater a plant and leave it sitting with it's draintray full of water the roots start to rot and the soil turns sour from the soggy peat moss and the fungus gnats come out of nowhere.  It is good practice to empty the drain trays of plants a few hours after you water them.  The soil has soaked up as much water as possible and at that point if it sits with a tray full of water you will have problems. Good luck.

Darlene