Where are common breeding grounds for fungus gnats?

Potted plants serve as ideal breeding grounds for fungus gnats due to the moist, organic material found in the potting soil. These insects thrive in environments where there is decaying organic matter, which provides both nourishment and a suitable habitat for their larvae. The moisture level in the soil, particularly when overwatering occurs, creates an environment that is conducive to the reproduction of fungus gnats. Their life cycle benefits from such conditions, making potted plants the primary location for their breeding activities.

Other potential options might not present the same ideal conditions. Attics, while possibly damp, typically lack the rich organic matter where fungus gnats flourish. Similarly, areas under furniture or near water sources do not inherently provide the necessary combination of moisture and organic substrate that potted plants do, thereby making them less suitable for breeding.