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Insect Pest Control

Q.Fungus Gnat Infestation For Months

Zone Boston | Beantownbeans added on June 18, 2020 | Answered

I have a lot of house plants that I started indoors in March and have begun to transition onto my balcony when the weather is nice. Back in March, my first plant (tomatoes) began to get gnats after I overwatered it. Since then, my plant collection has grown to include herbs, peppers, zucchini, spider plants, and more. I’ve tried soap and water spray, spraying neem oil weekly, cinnamon, recently did a neem/water drench, not watering for as long as possible, and using sticky traps. I cannot get rid of them and they’re driving me crazy as I live in a small apartment and they’re basically in all my plants. They definitely come in waves like I’ll do something and there won’t be any for a few days and then all of a sudden they come back super strong. How can I get rid of them for good? I was thinking maybe just buying all new soil, but I’m worried that it will waste money if the gnats just find a way back. Please help!

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Certified GKH Gardening Expert
Answered on June 19, 2020

Fungus gnats get their name from the food that they eat- Fungus.

They are present when the soil starts to rot from drastic overwatering, and are a symptom of a much bigger problem- Root Rot.

They are trying to eat what they can and are helping to save the plants from death.

Since you are indoors, watering on schedule will be a no-go. You will need to water once the soil is COMPLETELY DRY down to about 2 or 3 inches. If your containers to not have drainage to allow all extra water out, then you will need to wait until the soil is bone dry down to half way, or even close to the bottom of the container.

Once you correct the watering and get rid of the fungal infections, the gnats will go away since they will not have a food source.

If you rid the gnats before you correct infection, then your indicator is now gone, and taking out the fungus can become guesswork.

You will need a fungicide. With that and correct watering habits, your plants can be saved.

Here are some articles that will help:







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