I've been battling a terrible fungus gnat problem ever since we potted around 80 indoor plants for an office in April. Initially, we faced drainage issues, which led us to go with pots that lack drainage—something I usually avoid but thought necessary for keeping the plants hydrated in the office heat. Unfortunately, as the summer progressed, the fungus gnats showed up in full force, affecting every single plant. We tried different pesticides continually, but they didn't yield lasting results. After removing all the plants and repotting them with fresh soil, the gnats returned after a few weeks. Now, I've turned to nematodes, but they don't seem effective either. Could the heat and excess light in the office, or our earlier pesticide use, be affecting their success? Any tips would be appreciated!
3 Answers
Have you considered using fly tape? I know it sounds super basic, but I’ve managed to clear bad infestations with it quickly—usually within a couple of weeks. Just hang them around the plants, and you'll be surprised at how much it helps!
I had a similar issue when I used Miracle-Gro potting mix; it turned out to be full of junk! After ditching that brand, I added two drops of BMC Biological Mosquito Control per gallon of water to deactivate the gnat eggs—definitely worth a try! Also, check out the Zevo insect traps; they're way more effective than standard sticky traps.
Thank you so much! I'll be looking into both of those options for sure.
You might need to be patient with the nematodes. If you've used pesticides, the soil can take a while to recover, making it tough for the nematodes to do their job effectively. A fine layer of sand on top could help deter gnats as well, but be careful not to disturb it when watering.
That was our concern! We've been trying to manage it carefully since we opted for pebbles initially.
Thanks for the suggestion! We've actually tried sticky traps on every plant since day one, but they haven't made a dent in the problem.