Question
I recently bought Catcus soil to plant cuttings from a Christmas catcus from my mother-in-law.  It has flying gnats in an around it. None of my other plants in this room have them and would like to prevent that from happening. I have it in a clay pot so it does not stay wet.  What can I use that won't hurt my cactus?

Answer
Hi Melanie,

You have a couple of options. One is to take the contaminated cactus soil back to the retailer and get an exchange or your money back. Instead of packaged cactus soil, you might consider making your own from equal parts of peat moss and perlite.

Fungus gnat larvae require decaying organic matter to survive. Cactus soil is usually very sandy, so if you spread it out in an open pan and let it dry completely, in the sun or even in an oven at a low temp, that should eliminate all moisture and kill the larvae.

Once you have done that, it should be fit for use with your cuttings.

Please let me know if any of this is unclear or if you have any additional questions.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

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