I'm a newbie plant parent with six plants I've cared for over the last four years. They were doing great until I noticed they seemed rootbound this winter. After repotting them in the spring with soil from a local nursery, I think I accidentally introduced fungus gnats from the soil. I've been using yellow sticky traps, spraying with neem oil, and watering with mosquito bits weekly, but the issue just won't go away. I already lost one plant because it dried out, and I'm worried I might lose my favorite one, which holds sentimental value from my time abroad. Are these gnats common in pre-packaged soil? Should I continue trying, or is it time to throw in the towel?
3 Answers
Have you tried bottom watering instead of top watering? It worked wonders for my fungus gnat issue. Also, consider baking your new soil to kill any eggs before using it next time. Using sticky traps and possibly some light traps can help minimize the gnat population while you tackle the source of the problem.
Honestly, gnats seem to come with about 30% of the packaged soils. I’ve had luck with diatomaceous earth; just let the top layer of soil dry, sprinkle some on top and in the drainage holes, and be patient. Sometimes, if the soil's dry enough, it might require a second treatment to fully get rid of them. They've definitely been a tough pest to shake off, but it is possible!
I totally feel your pain! I’ve been dealing with gnats as well. I started spraying my plants and soil with a diluted hydrogen peroxide solution, and it has really helped reduce their numbers. Make sure you target the fungus that's attracting them too—it might aid in getting rid of the problem faster. If you can, try focusing on the root cause rather than just the gnats.