Question
I noticed I have nats around the soil and rocks of my indoor Bonsai tree.  I am watering and misting it daily per the directions.  How do I get rid of the nats without killing my Bonsai tree?

Answer
Hi Rowena,

The presence of fungus gnats is a good indication that the soil is staying too moist and the roots are rotting. The fungus gnat larvae feed on the decaying roots. I cannot say just how often your Bonsai should be watered, but is is apparent that you are watering too frequently.

I suggest watering no more than twice per week as long as there is no evidence that the plant is wilting. This will help curb the root rot which, unlike the gnats, will kill the plant.

Adult fungus gnats fly around and are an annoyance, but they are not harmful to people. Each gnat lives for about 5 days. The trick is to get rid of the next generation - the gnat larvae that live in the top layer of the soil.

Try to keep the soil as dry as possible. Remove all loose soil and rocks from the surface and place ?inch slices of raw potato on the surface of the soil. These potato slices will attract the gnat larvae. After a day or so, discard the slices along with the larvae inside. Repeat this until there are no more larvae in the potato.

Please let me know if any of this is unclear or if you have any additional questions. If you would like to e-mail me some photos, I may be able to provide some additional insights.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

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