You see them everywhere. You grab the fly swatter, swing wildly and yet they keep coming back. Sound familiar? That's exactly the problem with fungus gnats. A fly swatter solves nothing, and here's why.
The problem is underground
Adult fungus gnats only live a few days. During that time they mate and females lay up to 200 eggs in moist potting soil. Those eggs develop into larvae that feed on organic material. Kill an adult and there are already dozens of eggs ready to hatch. You're treating the symptom, not the cause.
Why do they multiply so fast?
The lifecycle of a fungus gnat takes just three to four weeks in warm conditions. A female lays hundreds of eggs during her short life. By the time you see the first adults, the next generation is already on its way underground. Without tackling the breeding site, you'll always be one step behind.
What actually works?
The solution lies in the pot. Let the top layer of soil dry out between waterings, as larvae need moisture to survive. Yellow sticky traps near plants help catch adults and break the reproductive cycle. For persistent cases, replace the top layer of soil with sand or perlite.
The fly swatter as a last resort
That doesn't mean you should throw the fly swatter away entirely. As a supplement to the right approach, it can help catch the odd stray adult. But as the only measure, it's an exercise in futility.
Tackle the problem at the source and you'll be rid of fungus gnats within a few weeks.