If tiny black flies are hovering around your indoor plants, you are not alone. Fungus gnats are a major issue across South East Queensland right now, especially after our humid summer.
I call them the headlice of the plant world. If you do not treat the entire life cycle, they keep coming back. The adults are irritating, but the real problem is in the soil where larvae feed on organic matter and roots.
Overwatering is usually the trigger. Damp soil creates the perfect breeding ground. Unfortunately, many commercial potting mixes already contain gnat eggs, which is why infestations often appear soon after repotting.
Below is our go to treatment. I also share step by step videos on Instagram if you prefer to see the process in action.
Start with the larvae. Use 3 percent hydrogen peroxide diluted with water. I recommend a 1 to 10 ratio for general use, but you can increase to 1 to 4 for heavier infestations. Drench the soil thoroughly. The fizzing action helps eliminate larvae in the potting mix.
Next, deal with the adults. Sticky traps will capture flying gnats and interrupt the breeding cycle.
Finally, create a barrier. We use Gnat Off as a top dressing to stop adults laying eggs in the soil. It also contains neem granules, which help deter pests from living in your mix.
For long term prevention, make your own soil blend and include neem granules from the beginning. Healthy plants in well draining soil are far less attractive to gnats.
If fungus gnats are driving you mad, visit Bespoke Plants at 26 Bulcock St, Caloundra.
