Things You'll Need
Fresh potting soil
Apple cider vinegar
Fruit flies are tiny creatures, possibly tiniest flies you'll ever come across in your home. These winged insects have light brown bodies and bright red eyes, which are sometimes hard to detect with the human eye. Commonly hovering over rotting vegetables and fermenting fruits, fruit flies may sometimes occupy indoor plant soils, if decaying plant matter is in close proximity to the rotting fruit and vegetables.
Discard old plant bulbs, decaying plant matter and the affected indoor soil. Throw away any nearby overripe fruits or vegetables.
Remove any attached dirt from the roots of your plants. Spray the plant with an insecticidal soap to kill any fruit fly larvae or eggs. Repot the houseplants in fresh potting soil.
Prepare a trap for the fruit flies. Fill the bottom 1/2 inch of a clear glass jar with apple cider vinegar. Cover the jar with a piece of plastic wrap secured with a rubber band.
Poke a few holes in the top of the plastic wrap, which allow the fruit flies to enter. Once the fruit flies enter the jar they will not be able to exit.
Set the jar in the immediate area of your houseplants. Check the jar frequently for trapped fruit flies. After a few days, the fruit flies should drown in the apple cider vinegar. Discard the vinegar and dead fruit flies in the toilet, rinse the jar and refill with fresh apple cider once every two weeks.
If you don't have apple cider vinegar, fill the bottom of the jar with 1/4 cup of warm water, 1 tsp. of sugar and a packet of yeast.
Never use outdoor garden soil for indoor plants. Garden soil contains pests and diseases that can transfer to your houseplants.