I have a fungus gnat problem with my houseplants, I’ve kept them relatively under control using Mosquito Dunks in my watering can since August and some yellow sticky traps but I can’t seem to eradicate them. I was considering buying nematode pot poppers but I’ve never used them before so I was wondering if anyone had any tips for application. All my plants are still relatively small so I don’t have many large pots for any of them (most are between 4-10").
Any and all recommendations welcome, having pests is really taking all the joy out of having plants. I’m in Canada so a lot of pesticides aren’t available to me.
UPDATE: I figured I’d update this post incase someone comes looking for solutions and sees this. I ended up going with a top layer of silica sand (2-4 mm in size) on all of my pots. I continued with the BTI water, let my plants completely dry out between waterings, and bottom-watered most of my plants. I haven’t seen a fungus gnat in about 2 weeks so I think I have been successful in eradicating them. Will update again if this changes.
Update 2: I take back the update, they’re still here… I’m so over the freaking gnats.
This may be a bit of an unusual recommendation, but I’ve found biological warfare to be the best solution for fungus gnats: Drosera capensis, Cape sundews, are like nature’s bug vacuum.
There is a bit of time waiting for the plant to get ready to go, maybe a month to six weeks, but they require virtually no care aside from ensuring they’re in a bath of water at all times, and they absolutely EVISCERATE gnat populations. I used to have a terrible problem with them until last year when I got my first D. capensis, and roughly counting, one plant in a month caught over 170 bugs. They’re super fun to own and their colors are dazzling.
https://highlandmoss.com/wp-content/uploads/2022/03/IMG_3733-scaled.jpg
https://preview.redd.it/because-fungus-gnats-carnivorous-plant-haul-v0-8k97rhklvalb1.jpg?width=1080&crop=smart&auto=webp&s=2bfdad871281b204f19eec0985141d261ec6f156
Thank you for the recommendation! I’ve definitely considered carnivorous plants. Actually I ended up throwing all my plants in water last month (except for some succulents which weren’t part of the problem) to convert all of my plants to a semi-hydro system instead. I haven’t seen a fungus gnat since! Once it warms up outside and I can rinse off the substrate with a hoze I’ll be potting them up in a soilless mix.