No, vinegar get rid of fungus gnats doesn't tell the full story. Vinegar traps catch adult gnats that fly into them, but they don't touch the larvae, eggs, or pupae in your soil. About 90% of your gnat problem lives underground. Vinegar alone won't fix that.
Here's how to apple cider vinegar trap gnats if you want to try it as part of a bigger plan. Fill a small jar with about half an inch of apple cider vinegar. Add 2 to 3 drops of dish soap and mix it gently. The vinegar's smell draws adult gnats toward the jar. The soap breaks the water's surface tension so gnats sink and drown instead of floating on top.
I set up these traps near every one of my plants during a bad outbreak last year. Each morning I found 20 to 30 dead gnats floating in the jars. It felt like real progress. But after two full weeks of filling traps and counting bodies, the number of gnats in my home hadn't dropped at all. New adults kept coming out of the soil faster than my traps could catch them. I was bailing water from a sinking boat without plugging the hole.
The issue is simple math. A single female gnat lays up to 200 eggs in your soil's top layer. Those eggs hatch in 4 to 6 days, and the larvae munch on roots for about two weeks before turning into adults. Your vinegar jar on the shelf does nothing to stop this cycle underground. Even if your trap grabs every adult today, the next batch is already growing below the surface.
When you compare a vinegar trap for gnats to yellow sticky cards, you'll see another flaw. Sticky traps catch adults all day long without you having to refill them. They also give you a count of how many gnats are popping up each day so you can track your progress. Vinegar traps need you to refresh them daily because the scent fades and dead gnats pile up. They also pull in fruit flies and other bugs, so you can't use them to get a clear picture of your gnat numbers.
Use your vinegar traps as one small part of a larger plan. Set them out to grab some adults, but pair them with weekly Bti soil drenches that target your larvae where they live. Bti wrecks larval guts within 48 hours of them eating it. Let your soil dry between waterings too. This combo attacks the source of your problem, not just the few stragglers flying around.
I stopped leaning on vinegar once I started Bti drenches. Within three weeks, my sticky cards went from catching 25 adults per day to fewer than three. The vinegar jars weren't needed anymore because so few adults were left to trap. Put your energy into your soil and use traps for cleanup work, not the other way around.
Read the full article: Fungus Gnats: How to Identify and Stop Them
