When I keep any house plants indoors I notice a few little black flies flying around the house. I think they must come into the house on the soil in the plant pots, or be in some way related to the plants.

Is there a way to stop this happening? Can you add something to the top of the plant pot to stop this happening?

Julia, September 2009

The fly eggs are present on the leaves of the plant or in the soil - its the heat indoors that brings them to life. Your garden centre should be able to provide you with a spray that will prevent this.

John, September 2009